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Formalizing agro-ecological engineering for future-oriented land use studies
Abstract
Agriculture faces an array of interrelated problems that call for development of new and revision of existing cropping systems towards the multiple needs of the 21st century. Agro-ecological engineering approaches aimed at design and exploration of alternative land use systems at various scales may support the identification of appropriate land use options. Engineering approaches are based on mathematical representations of well-founded agro-ecological principles while taking into account available resources and prevailing land-related objectives. The goal of this paper is to contribute to the development of a formalized approach to engineer cropping systems at the land unit level that can be used as building blocks for systematic explorations of land use options at farm or regional scale. The approach for engineering cropping systems at the land unit level consists of three steps: (i) goal-driven design of cropping systems, (ii) quantification of biophysical production targets and (iii) definition of the optimal mix of inputs required to realize production targets. This paper describes the approach and illustrates it with examples from the Sudano-Sahelian zone of Mali. Explicit attention is paid to the required numerical tools and their application to analyze consequences of uncertainty in the performance of engineered cropping systems. Using numerical tools, uncertainty is made explicit with the aim to better manage or reduce it. Identification of uncertainty at the designer's desk allows taking uncertainty into account before applying engineered land use systems in regional model studies or testing such systems in practice. Problems related to the application of numerical tools are discussed, including the future role of agro-ecological engineering as independent discipline within agricultural science.
... nitrate leaching, pesticide run-off and biodiversity (Ten Berge and others 2000). An activity is characterised by a set of technical coefficients (TCs, or input-output coefficients) expressing the activity's contribution to the realisation of defined goals or objectives in modelling terms (Hengsdijk and van Ittersum 2003). Constraints are included to express farm level minimum or maximum quantities of input use or output marketing restrictions. ...
... A static model does not include a time step in the model. Although the model is static, the input and output coefficients of the agricultural activities take temporal interactions into account as ''crop rotations'' and ''dressed animal'' instead of individual crops or animals (Hengsdijk and van Ittersum 2003). Risk is taken into account with the Mean-Standard deviation method in which expected utility is calculated based on the expected income, the farm specific risk aversion parameter and the standard deviation of income (Freund 1956;Hazell and Norton 1986). ...
... The detailed survey was conducted by regional experts, who work regularly with farmers. A so called ''simple survey'' was conducted to collect a reduced data set in 16 EU regions for arable, livestock and perennial activities comprising economic variables (e.g., product costs and prices), yields, composition of rotations and some aggregate physical variables describing input use (e.g., nitrogen use per crop and total (Hengsdijk and van Ittersum 2003) are algorithms to process data and information into technical coefficients directly usable by a mathematical programming model (e.g., FSSIM-MP) and cropping systems models (e.g., APES). The Current Activities component (CAC) of the TCG processes survey data into compatible inputs for FSSIM and links them to regional farm types, while calculating an average over several years for the observed cropping pattern, product price and yield variability for these farm types using data from the FADN-based farm typology (Andersen and others 2007). ...
... EIA: environmental impact assessment EIA: Rodrigues et al. (2003) Evaluation of the sustainability of agricultural technology innovation by the EIA method: Field-Farm (Brazil) MAS: multi-agent system MAS-1: Petit et al. (2001) Evaluation of the quantity and quality of groundwater by using hydrological, agronomic and socio-economic models in a multi-agent system: Beauce aquifer (France) MAS-2: Becu et al. (2004) Modelling the impact of catchment irrigation management under social and agronomic constraints in a multi-agent system: catchment scale (Thailand) LP: linear programming LP-1: Zander and Kächele (1999) Optimisation of different production systems described at the farm level with multiple goal linear programming: extrapolation to a regional scale (Germany) LP-2: Hengsdijk and van Ittersum (2003) Optimisation of different production systems to maximise the production targets whilst minimising impacts: farm or regional scale (Mali) AEI: agro-environmental indicators AEI-1: ECNC (2000) Development of ''Driving force'', ''State'', and ''Response'' indicators for environmental impact assessment mainly at macro-level: European agriculture AEI-2: Rasul and Thapa (2004) Evaluation of farming sustainability by ecological, economic and social indicators: micro-regions (Bangladesh) (Heathwaite, 2003). This kind of approach thus assumes routine use of Geographical Information Systems (GIS) to superimpose several sets of spatial information (Chen et al., 2001). ...
... The indicators used in LP approaches may be means-based, such as the quantity of nitrogen fertiliser used, of the emission type, such as emission of eutrophying substances, or of the state type, such as soil quality (Zander and Kächele, 1999;Hengsdijk and van Ittersum, 2003). AEI approaches may be based either on means-based indicators such as the quantity of pesticides used or on effect-based indicators like the amount of soil eroded (ECNC, 2000). ...
... LP approaches involve a classification of the agronomic properties of the study zone as a function of soil type, land use, rainfall, etc. (LP-1 and LP-2, Table 4). The presumed homogenous units may vary from the field to regions of more than 21,000 km 2 (Hengsdijk and van Ittersum, 2003). GISs are routinely used to delineate these homogeneous units. ...
Environmental impact assessment for a farming region : a review of methods
... In fact, agroecological engineering covers two main approaches that differ in terms of methodological issues and the knowledge produced. One approach, related to integrated resource management, is occasionally referred to as agroecological engineering (Hengsdijk and van Ittersum, 2003). It addresses agricultural sustainability at a larger scale to support public policies (Hengsdijk and van Ittersum, 2003) and at a smaller scale to accompany farmers in their management (Jakku and Thorburn, 2010). ...
... One approach, related to integrated resource management, is occasionally referred to as agroecological engineering (Hengsdijk and van Ittersum, 2003). It addresses agricultural sustainability at a larger scale to support public policies (Hengsdijk and van Ittersum, 2003) and at a smaller scale to accompany farmers in their management (Jakku and Thorburn, 2010). Agroecosystem models used in these studies are based on available and up-to-date agroecological knowledge. ...
... Most literature about action-oriented agronomy describes decision-support systems (DSSs). Agroecological engineering approaches for supporting public policies consist of (i) ''goal-driven design of cropping or farming systems, (ii) quantification of production targets, and (iii) definition of the optimal mix of inputs required to realise production targets'' (Hengsdijk and van Ittersum, 2003). Usually such research is at least at a regional scale and involves the use of computer models to predict consequences of management options on performance or to design cropping systems for a given context. ...
One way to improve sustainable agriculture is to use existing resources and technologies better by finding synergies between plants, soil, climate and management practices. However, for many agricultural situations there is a lack of understanding about the structure of biological and ecological relationships that drive resource dynamics. Therefore, it remains a challenge to build tools for farmers and advisors that fit with these uncertainties and that are generic. In this paper, we define an “agroecological engineering” approach from a combination of several methods of knowledge production: analytical methods that are de-contextualised (e.g. experimentation, on-farm observations) and holistic and contextualised methods based on workshops and training sessions with stakeholders. The key feature of the approach is the construction of a “boundary object”, i.e. a support facilitating the communication between researchers and stakeholders, which evolves from a premise into a support tool during the course of a research project and then helps organise knowledge flows between methods. Two long-term studies involving grassland management were used to illustrate the approach. Based on these examples and on the literature, we show that the approach needs to address four issues for defining generic operational tools to find site-specific solutions: aims and principles of the approach, development of tool support throughout a research project, knowledge flow among knowledge-production methods, and the function of agroecosystem models. A remaining scientific challenge is the extrapolation of tool prototypes outside the case studies on which they were based.
... EIA: environmental impact assessment EIA: Rodrigues et al. (2003) Evaluation of the sustainability of agricultural technology innovation by the EIA method: Field-Farm (Brazil) MAS: multi-agent system MAS-1: Petit et al. (2001) Evaluation of the quantity and quality of groundwater by using hydrological, agronomic and socio-economic models in a multi-agent system: Beauce aquifer (France) MAS-2: Becu et al. (2004) Modelling the impact of catchment irrigation management under social and agronomic constraints in a multi-agent system: catchment scale (Thailand) LP: linear programming LP-1: Zander and Kächele (1999) Optimisation of different production systems described at the farm level with multiple goal linear programming: extrapolation to a regional scale (Germany) LP-2: Hengsdijk and van Ittersum (2003) Optimisation of different production systems to maximise the production targets whilst minimising impacts: farm or regional scale (Mali) AEI: agro-environmental indicators AEI-1: ECNC (2000) Development of ''Driving force'', ''State'', and ''Response'' indicators for environmental impact assessment mainly at macro-level: European agriculture AEI-2: Rasul and Thapa (2004) Evaluation of farming sustainability by ecological, economic and social indicators: micro-regions (Bangladesh) (Heathwaite, 2003). This kind of approach thus assumes routine use of Geographical Information Systems (GIS) to superimpose several sets of spatial information (Chen et al., 2001). ...
... The indicators used in LP approaches may be means-based, such as the quantity of nitrogen fertiliser used, of the emission type, such as emission of eutrophying substances, or of the state type, such as soil quality (Zander and Kächele, 1999;Hengsdijk and van Ittersum, 2003). AEI approaches may be based either on means-based indicators such as the quantity of pesticides used or on effect-based indicators like the amount of soil eroded (ECNC, 2000). ...
... LP approaches involve a classification of the agronomic properties of the study zone as a function of soil type, land use, rainfall, etc. (LP-1 and LP-2, Table 4). The presumed homogenous units may vary from the field to regions of more than 21,000 km 2 (Hengsdijk and van Ittersum, 2003). GISs are routinely used to delineate these homogeneous units. ...
The methods currently used for assessing the environmental impact of agriculture on the scale of a farming region cover a wide range of objectives, users and concepts. To illustrate this variety, this article provides an analysis of six main types of method: environmental risk mapping, life cycle analysis, environmental impact assessment, multi-agent system, linear programming and agro-environmental indicators. Eleven case studies, in which one of the six methods was applied, are used as data in this review. All methods are based on a set of environmental objectives. Some methods also take account of economic and social objectives to produce a more wide-ranging assessment of the sustainability of the agricultural system studied. Each method relies on indicators serving as criteria to evaluate whether the objectives have been attained. These indicators take account of local impacts such as noise, regional impacts such as eutrophication, or global impacts like the greenhouse effect. The characteristics required to develop a method for the environmental impact assessment of a farming region are discussed. The analysis of the interactions between farms is indispensable at this scale of analysis. Indicators based on the environmental effects of farming practices should take precedence over those based on the practices themselves, which do not provide a direct evaluation of environmental impact. Indicators which express an impact both per kg of product and per unit of land area used bring together the essential functions of agriculture, namely production and the occupation of the countryside. The assessment methods should include an analysis of the uncertainty associated with the results. Lastly, the method should be validated with respect to (i) the conception of the method and its indicators, (ii) the consistency of the values of the indicators in relation to observed values, and finally (iii) the suitability of the indicators and more generally of the assessment method for the end users.
... nitrate leaching, pesticide run-off and biodiversity (Ten Berge and others 2000). An activity is characterised by a set of technical coefficients (TCs, or input-output coefficients) expressing the activity's contribution to the realisation of defined goals or objectives in modelling terms (Hengsdijk and van Ittersum 2003). Constraints are included to express farm level minimum or maximum quantities of input use or output marketing restrictions. ...
... A static model does not include a time step in the model. Although the model is static, the input and output coefficients of the agricultural activities take temporal interactions into account as ''crop rotations'' and ''dressed animal'' instead of individual crops or animals (Hengsdijk and van Ittersum 2003). Risk is taken into account with the Mean-Standard deviation method in which expected utility is calculated based on the expected income, the farm specific risk aversion parameter and the standard deviation of income (Freund 1956;Hazell and Norton 1986). ...
... The detailed survey was conducted by regional experts, who work regularly with farmers. A so called ''simple survey'' was conducted to collect a reduced data set in 16 EU regions for arable, livestock and perennial activities comprising economic variables (e.g., product costs and prices), yields, composition of rotations and some aggregate physical variables describing input use (e.g., nitrogen use per crop and total (Hengsdijk and van Ittersum 2003) are algorithms to process data and information into technical coefficients directly usable by a mathematical programming model (e.g., FSSIM-MP) and cropping systems models (e.g., APES). The Current Activities component (CAC) of the TCG processes survey data into compatible inputs for FSSIM and links them to regional farm types, while calculating an average over several years for the observed cropping pattern, product price and yield variability for these farm types using data from the FADN-based farm typology (Andersen and others 2007). ...
Bio-economic farm models are tools to evaluate ex-post or to assess ex-ante the impact of policy and technology change on agriculture, economics and environment. Recently, various BEFMs have been developed, often for one purpose or location, but hardly any of these models are re-used later for other purposes or locations. The Farm System Simulator (FSSIM) provides a generic framework enabling the application of BEFMs under various situations and for different purposes (generating supply response functions and detailed regional or farm type assessments). FSSIM is set up as a component-based framework with components representing farmer objectives, risk, calibration, policies, current activities, alternative activities and different types of activities (e.g., annual and perennial cropping and livestock). The generic nature of FSSIM is evaluated using five criteria by examining its applications. FSSIM has been applied for different climate zones and soil types (criterion 1) and to a range of different farm types (criterion 2) with different specializations, intensities and sizes. In most applications FSSIM has been used to assess the effects of policy changes and in two applications to assess the impact of technological innovations (criterion 3). In the various applications, different data sources, level of detail (e.g., criterion 4) and model configurations have been used. FSSIM has been linked to an economic and several biophysical models (criterion 5). The model is available for applications to other conditions and research issues, and it is open to be further tested and to be extended with new components, indicators or linkages to other models.
... Dans les systèmes agricoles, une activité est définie comme une séquence cohérente d'opérations techniques qui se traduisent par la production de biens commercialisables (par exemple des grains de céréales) et/ou utilisables au sein d'une exploitation (par exemple des fourrages), ainsi qu'à des externalités (par exemple, des nitrates lixiviés) (Hengsdijk et al., 1999). Chaque activité est caractérisée par des coefficients techniques qui spécifient la contribution de celle-ci à la réalisation d'objectifs multiples (Hengsdijk et al., 2003). Dans les paragraphes suivants, nous détaillons la caractérisation de chacun de ces critères. ...
... In explorative studies, BEM are used for the evaluation of the plausible consequences of a combination of external trends and technological changes (including alternative agricultural activities) combined in a scenario (Hengsdijk et al., 1998;Hengsdijk et al., 2003;Belhouchette et al., 2010). Lopez-Ridaura (2005a) identified three main types of scenarios for explorative studies: (i) evaluating the consequences of conflicting objectives by contrasting different objective functions or by maximizing or minimizing one objective while setting another objective as constraint (Lu et al., 2004;Lopez Ridaura, 2005b) (Waithaka et al., 2006;Cittadini et al., 2008) and (iii) changing one of the parameters of the model such as the price of a given product, subsidies or taxes (Semaan et al., 2007). ...
Les systèmes agricoles sont en constante évolution sous les effets conjugués d'innovations techniques et organisationnelles et de changements du contexte socio-économique. A l'échelle d'un territoire, des acteurs locaux peuvent encourager et accompagner des changements de ce type s'ils ont une vision claire de leurs impacts potentiels. L'objectif de cette thèse est d'élaborer et d'appliquer une démarche permettant d'assister agriculteurs et autres acteurs locaux d'un territoire dans la construction et l'évaluation de scénarios d'évolutions des systèmes agricoles. Une démarche basée sur des approches permettant une analyse prospective, multicritères, multi-échelles et participative d'évaluation des systèmes agricoles a été développée. Elle a été mise en oeuvre en Camargue (sud-est de la France), avec des exploitants céréaliers et des acteurs de la production agricole et de la gestion du territoire. Des scénarios portant sur la réforme de la politique agricole commune (PAC) en 2012-2014, ainsi que sur des objectifs nationaux de réduction de la consommation de pesticides et de développement de l'agriculture biologique ont été développés. Ces perspectives d'évolution des systèmes agricoles camarguais ont été évaluées, via la formalisation de nombreuses données et connaissances. Deux outils de modélisation ont été utilisés : un modèle multi-agent a permis la mise en place de séances de simulation interactives avec des agriculteurs, et un modèle bioéconomique a été développé et utilisé avec des acteurs locaux tels que le syndicat des riziculteurs et le parc naturel régional. Les scénarios portant sur la réforme de la PAC ont confirmé la dépendance des exploitations rizicoles aux subventions. Des agriculteurs ont testé différentes stratégies d'adaptation de leurs exploitations à la suppression de l'aide couplée à la production rizicole. Ces stratégies, souvent basées sur la diversification des activités ou sur la conversion à l'agriculture biologique, ne permettaient pas de compenser les pertes économiques liées à la disparition de l'aide couplée. A l'échelle du territoire, ces stratégies réduiraient fortement la surface cultivée en riz, avec des impacts importants sur d'autres activités en lien avec la production agricole. Cependant ces stratégies vont dans le sens des objectifs gouvernementaux de réduction des impacts de l'agriculture sur l'environnement. Des scénarios portant spécifiquement sur ces objectifs ont permis d'identifier des marges de manoeuvre importantes au niveau des exploitations céréalières camarguaises. Cette thèse propose un cadre pour la mise en oeuvre de démarches d'évaluation des systèmes agricoles dans un territoire, qui associe les agriculteurs et les acteurs locaux à différentes étapes, depuis leur engagement pour le choix des scénarios, l'acquisition et l'analyse des données, la construction des outils de simulation et l'évaluation de scénarios. La combinaison de différents outils de modélisation pour la réalisation de réflexions collectives, pourrait contribuer à la mise en place d'actions pour un développement durable de l'agriculture.
... Hengsdijk & van Ittersum (2003) presented an agro-ecological modelling approach, converting information on specific aims for agricultural systems into targeted identification and quantification of land use systems and their management options. In the approach, process based knowledge and empirical data regarding agronomic relationships are integrated and synthesised, using a variety of numerical tools, while taking into account available resources and prevailing land-related objectives (ten Berge et al., 2000). ...
... Based on the above regional context, arable cropping systems in NutMatch were described according to so-called design criteria (Hengsdijk & van Ittersum, 2003), each represented by a number of variants. Our design criteria were the composition of the rotation, nutrient sources used, and the level of N supply to individual crops relative to their full N demand at economically optimal N rate ( Table 1). ...
Crop production and soil fertility management implies a multitude of decisions and activities on crop choice, rotation design and nutrient management. In practice, the choices to be made and the resulting outcomes are subject to a wide range of objectives and constraints. Objectives are economic as well as environmental, for instance sequestering carbon in agricultural soils or reducing nitrogen losses. Constraints originate from biophysical and institutional conditions that may restrict the possibilities for choosing crops or using specific cultivation and fertilization practices. To explore the consequences of management interventions to increase the supply of organic C to the soil on income and N losses, we developed the linear programming model NutMatch. The novelty of the model is the coherent description of mutual interdependencies amongst a broad range of sustainability indicators related to soil fertility management in arable cropping, enabling the quantification of synergies and trade-offs between objectives. NutMatch was applied to four different crop rotations subjected to four fertiliser strategies differing in the use of the organic fertilisers cattle slurry, pig slurry or compost, next to mineral fertiliser. Each combination of rotation and fertiliser strategy contributed differently to financial return, N emissions and organic matter inputs into the soil.
... The eco-engineering approach, combined with agro-ecological concepts, makes it possible to systematically design technically feasible land use systems that meet clearly expectations different scientific and social groups. According to Hengsdijk and Ittersum (2003) engineered cropping systems are not blueprints for crop cultivation but they describe a wide range of technically feasible and efficient systems, each of which is uniquely characterized by its inputs and outputs. Typically, these so-called technical coefficients include primary outputs (i.e., crop yield and residues), unavoidable secondary outputs (i.e., emission of biocides and nutrients, change in natural resource stock, etc.), and input requirement (i.e., labor, fertilizer, implements, etc.). ...
The intensification of agriculture over the last century has significantly increased agricultural production per unit area, while at the same time depleting natural resources and degrading the agro-ecosystem. A new approach is needed to restore the environment to pre-industrial levels and return to nature. There is a growing awareness among scientists from different disciplines that innovations in cropping system design can be effective in promoting agri-environmental changes. Eco-engineers see the need for a renewed focus on biodiversity in the agri-environment, which is visible through the inclusion of flowers and herbs in cropping system design. Flower strips and herb/flower mulches have been shown to provide a wider range of ecosystem services through increased interactions between plant species, spatio-temporal niche diversity and greater diversity of field habitats. The Green Revolution model has helped us meet the increasing demand for food over the past half century. Achieving stable crop productivity in the future will depend heavily on our ability to design of novel farming systems that bring farming practices closer to nature.
... Conditional Random Fields (CRFs) were proposed in [19] for application to annotation problems [20], where they proposed conditional random fields by changing the local normalisation used in maximum entropy Markov models to global normalisation in the computation of probability distribution. Subsequently, conditional random fields began to be widely studied in various fields. ...
With the establishment and rapid development of the China (Shanghai) Pilot Free Trade Zone (FTZ), the scale of enterprises in the zone has grown rapidly. This paper takes the actual needs of the Shanghai FTZ as the background, extracts key information such as entities from the Big Data related to Internet enterprises, further constructs the enterprise knowledge graph, and applies it to the supervision and service of the FTZ. The enterprise knowledge graph is constructed using the Neo4j graph database. To verify the effectiveness of the named entity identification and relationship extraction methods proposed in this paper, experiments were conducted to validate them, and both achieved good results.
... Inputs and outputs of current agricultural activities (arable crops or crop rotations; perennials such as grassland, orchards, vineyards; keeping livestock) are specified based on surveys and databases operating on sampled farms across the EU-25, such as the FADN and SEAMLESS database. Alternative activity technologies are systematically generated using agronomic knowledge rules (Dogliotti et al., 2003;Hengsdijk and van Ittersum, 2003) but can also be linked to crop growth models. Its mathematical programming component is a comparative, static model with a non-linear objective function maximizing expected income considering risk aversion regarding prices and yields. ...
Context:
Past reviews of policy impact assessment studies using bio-economic farm models (BEFM) called for the development of a generic and modular implementation that can be maintained by a network of modellers. A main reason for these calls is the project-oriented way in which model developers receive funding. It favours the development of new models with case-study specific features over the maintenance and extension of well-tested, more generic ones which allow comparing results in a consistent way across many case-studies. The demand for more generic tools also reflects the dynamic landscape of policy measures within larger policy frameworks like the Common Agricultural Policy (CAP). These policy frameworks move increasingly away from a ‘one-size-fits-all’ approach of policy design towards more flexible systems, giving greater freedom to shape, implement, and target policy measures to specific regions, farm management systems and farm types. This creates new challenges for model-based impact assessment as applied models have to reflect the variety of policy measures and characteristics of targeted farmers and rural communities.
Objective:
The aim of this paper is to first address key questions regarding the functionality and implementation of such a modular BEFM that can be maintained and expanded by a user group, and second to develop concrete proposals of necessary model features, model design and shared development.
Methods:
This paper builds on literature research, including a detailed review of four models that are used extensively for impact assessment within the EU and were developed by multiple teams over a longer period of time. From there, necessary and desirable features of a generic and modular BEFM are identified and requirements for model design regarding modularity, software engineering, and shared development are discussed.
Results and conclusions:
This feeds into the development of concrete proposals of how modularity and flexibility can be addressed in the development, application and maintenance of a BEFM. At the end, a list of design decisions and implementation steps is proposed to build a modular BEFM that can be maintained by a network of researchers.
Significance:
The concept for a network-based generic and modular bio-economic farm model responds to the demand for analytical tools in agricultural policy impact analysis. The paper develops a research agenda to overcome observed limitations in the current landscape of such models.
... This approach was first adopted in China in 1978 (Mitsch et al., 1993) and has been applied to address sustainability concerns in many other ecosystems, including agro-ecosystems (Mitsch and Jørgensen, 2003;Power, 2010). This strategy relies on the use of internal ecological processes, not only to restore the normal function of a given ecosystem but also to prevent further disruption of other ecosystems (Hengsdijk and Van Ittersum, 2003). Soil supports the growth of different microbial populations, many of which are involved in providing different categories of soil ecosystem services, directly or indirectly, such as nutrient cycling, organic matter degradation, contaminants removal, supporting soil fertility, resistance to different stresses, production of bioactive compounds that stimulate plants growth and other beneficial effects (Barrios, 2007;Wagg et al., 2014;Saccá et al., 2017). ...
Biological nitrogen fixation (BNF) refers to a bacterially mediated process by which atmospheric N2 is reduced, either symbiotically or non-symbiotically, into ammonia (NH3) in the presence of the enzyme complex nitrogenase. In N2-fixing grain legumes, BNF is often hampered under low phosphorus (P) availability. Phosphorus plays a vital role in BNF, and the P status of legume, particularly nodules, as well as P availability in the rhizosphere regulate BNF. Besides adequate P fertilization, to ensure nodule functioning, other plant traits (i.e., extensive rooting system and their spatial distribution, hyper-nodulation, root exudates, rhizosphere acidification, and heterogeneity) contribute to greater P uptake and hence BNF. The positive interaction between P availability and BNF can be exploited by beneficial soil P solubilizing microorganisms (PSM). These microorganisms can increase plant-available P by modifying either soil processes in the rhizosphere, or promoting plant traits that lead to increased P uptake by production of plant growth-promoting substances, both of which could indirectly influence the efficiency of BNF in legumes. In this review, we report on the importance of microbial P bio-solubilization as a pathway for improving BNF in grain legumes via PSM and P solubilizing bacteria (PSB). Because BNF in legumes is a P-requiring agro-ecological process, the ability of soil PSB to synergize with the rhizobial strains is likely a key belowground process worth investigating for advanced research aiming to improve rhizosphere biological functions necessary for sustainable legume-base cropping systems.
... FSSIM follows a primal-based approach, where technology is explicitly represented (Louhichi et al., 1999), using engineering production coefficients generated from agronomic theory and biophysical models (Hengsdijk and Van Ittersum, 2003). These engineering coefficients constitute the essential linkage between the biophysical and economic models. ...
10. Congress of the European Society for Agronomy: Multi-functional Agriculture - Agriculture as a Resource for Energy and Environmental Preservation, 2008/09/15-19, Bologna (Italie)
... Designing and management a landscape is complex and can neither be solved neither by a single discipline nor by changes only at one particular scale, plot, farm or region. Exploring these alternatives is possible with application of multidisciplinary researches with knowledge and information from different viewpoints and scales (Hengsdijk and Van Ittersum, 2003;Sadras and Calderini, 2009). So, this study present a new multidisciplinary approach for landscape planning in a spatial database frame work using Geographic Information System. ...
Sustainable land resource management depends on the good assessment and planning of current landscapes. This may be possible with application of multidisciplinary researches, as this study presented a multidisciplinary approach in a spatial database frame work using Geographic Information System. Agroecological zones concept is used to integrating and characterizing homogenous spatial units. This approach combine theme layers include of available water resources, climate, terrain and soil conditions, associated with land use and settlement patterns. Climatic indices layers, including of growing degree days, aridity index, length of growing period and freezing period were created using the correlation between climatic parameter and digital elevation model. Using this approach the Borujen watershed was divided in 28 agroecological zones which defined 3 landscapes or agricultural regions. The most important constraints for developing agriculture in landscape I has topographic, climatic and soil constrains, landscape II has topographic and soil constrains and landscape III has the some limitations of soil. Landscape I and II are much less attractive from an agricultural perspective. Landscape III is suitable for agriculture but, the potential for rainfed cropping system is limited by a lack of growing period during which neither temperature nor moisture is limiting to plant production. In general, the case study of the Borujen watershed indicated that this approach can be used for different scales and adaptive to the particular planning.
... Both the objective and the constraints can be set at the farm and/or regional levels (see Delmotte et al. (2016) for a detailed description of the model and its equations). The possible land uses are defined as agricultural activities following Hengsdijk and van Ittersum (2003), and are described in terms of agricultural inputs (e.g., fertilizer, pesticide, energy and water use, costs of production, labour) and outputs (e.g., yield of the crops, GHG and particulate emissions, energy and protein contents). This quantified information came from multiple sources of data: farmers' interviews, databases, crop modelling and expert knowledge (Delmotte et al., 2016). ...
European farmers are facing challenges that call for important transformations on their agricultural production systems, including an increasing number of regulations aimed at reducing environmental impacts from farming practices. Climate change is also expected to affect agricultural production in most European regions, and in Southern Europe this effect is expected to negatively impact yields. In this study, we present the application of an innovative participatory approach to assess the potential of innovative agricultural systems to reconcile environmental sustainability with economic viability while contributing to local and global food security. Our approach consisted of combining (1) the participation of local stakeholders in the design of narrative scenarios, and (2) an integrated assessment of scenarios through the calculation of indicators at different scale with a bio-economic model. We tested our approach with a case study situated in the Camargue region of Southern France. Rice is currently the main crop in this region, but farmers there face adverse economic conditions linked to the recent reform of European Common Agriculture Policy. After identifying the main drivers of change, local stakeholders developed narrative scenarios and described how farmers would adapt within the context of those changes. These elements were then translated into model inputs. At the regional level, the four scenarios led to variations in farmland acreage (28,000–33,000 ha), as well as the proportion of rice crops (19–75%) and areas cultivated under organic farming standards (8–43%). The four scenarios also led to different values for indicators of agricultural economic welfare, food production, and environmental impacts. Trade-offs between these indicators and the associated objectives assigned to agriculture were identified and discussed with the stakeholders. We end with a discussion of the limitations and advantages of our approach to the participatory development and assessment of locally developed narrative scenarios.
... Level Unit To formalize the description of the AS, we used the concept of 'agricultural activity' defined as a basic unit of description of the AS where each agricultural activity corresponds to a distinct combination of biophysical environment, crop type and management practice (Hengsdijk and van Ittersum, 2003). Five criteria for the definition of the agricultural activities were retained (Table 2). ...
Alternative agricultural systems, such as organic farming (OF), are promising options to sustain both agriculture productivity and environmental health. However, the adoption of OF by farmers is occurring more slowly than is advocated. A key factor limiting farmers is an inability to predict socio-economic consequences of converting to OF. To overcome this, we developed a novel method of integrated assessment of agricultural systems (IAAS) and applied it to scenarios of development of OF in the Camargue region, South of France. In collaboration with the local stakeholders, we characterized the agricultural systems at different spatial scales and defined scenario related to the future of agriculture and to OF. We then used agent-based modeling with farmers and bio-economic modeling with local stakeholders for scenario assessment. We examined the effects on the development of OF systems of key factors such as the ongoing reform in the European Common Agricultural Policy and the effects of regulations for decreased use of pesticides. The policy reform implied trends towards a diversification of crops and greater possibility for conversion to OF. Development of OF at the regional level led to improved environmental performance, but caused a decrease in profitability of the rice supply chains. In light of the observed trade-off between rice production and OF development, objectives and options towards more sustainable agricultural systems were discussed with farmers and local stakeholders. Stakeholders' assessment of the framework provided insights on the positive and specific aspects of the IAAS methodology requiring improvement. The complementarities of agent-based and bio-economic modeling provide stakeholders with a better-informed assessment of diverse scenarios, for the development of more sustainable agricultural systems.
... FSSIM follows a primal-based approach, where technology is explicitly represented (Louhichi et al., 1999), using engineering production coefficients generated from agronomic theory and biophysical models (Hengsdijk and Van Ittersum, 2003). These engineering coefficients constitute the essential linkage between the biophysical and economic models. ...
... In particular, the key issues are as follows: the combination of local knowledge and lay expertise with scientific knowledge (Dore et al. 2011), the design of new stakeholder organizations at the territory level, and the design of new coordination instruments combining scientific knowledge with perceptions, values and management skills of stakeholders . Overall, these issues illustrate the fact that agroecological engineering is a means to improve communication among research disciplines and between stakeholders and researchers (Hengsdijk and van Ittersum 2003). ...
... Designing and management a landscape is complex and can neither be solved neither by a single discipline nor by changes only at one particular scale, plot, farm or region. Exploring these alternatives is possible with application of multidisciplinary researches with knowledge and information from different viewpoints and scales (Hengsdijk and Van Ittersum, 2003;Sadras and Calderini, 2009). So, this study present a new multidisciplinary approach for landscape planning in a spatial database frame work using Geographic Information System. ...
Sustainable land resource management depends on the good assessment and planning of current landscapes. This may be possible with application of multidisciplinary researches, as this study presented a multidisciplinary approach in a spatial database frame work using Geographic Information System. ' Agroecological zones' concept is used to integrating and characterizing homogenous spatial units. This approach combine theme layers include of available water resources, climate, terrain and soil conditions, associated with land use and settlement patterns. Climatic indices layers, including of growing degree days, aridity index, length of growing period and freezing period were created using the correlation between climatic parameter and digital elevation model. Using this approach the Borujen watershed was divided in 28 'agroecological zones' which defined 3 landscapes or agricultural regions. The most important constraints for developing agriculture in landscape I has topographic, climatic and soil constrains, landscape II has topographic and soil constrains and landscape III has the some limitations of soil. Landscape I and II are much less attractive from an agricultural perspective. Landscape III is suitable for agriculture but, the potential for rainfed cropping system is limited by a lack of growing period during which neither temperature nor moisture is limiting to plant production. In general, the case study of the Borujen watershed indicated that this approach can be used for different scales and adaptive to the particular planning.
... The input and outputs coefficients of current activities in TechnoGIN are based on survey data. Alternative production activities, however, are quantified based on knowledge of the biophysical processes of plant and animal production, technical insights and land use related objectives (Hengsdijk and van Ittersum, 2003). For these activities yield levels were defined based on crop models (potential and water-limited yield levels), field experiments (rainfed and irrigated), expert knowledge and literature (Appendix 1). ...
... Design criteria. We used three sources of information to select design criteria, i.e., attributes distinguishing the different alternative production systems 22 , the state government fertilizer subsidy scheme, the recommendations of the national extension service and results from our own experiments and surveys. We did not find other sources of information that were locally relevant. ...
Farming systems in the Costa Chica region in Mexico face limitations linked to low yields and soil fertility degradation. Several alternative maize-based cropping systems have been proposed to improve current limitations. These field-level options need to be evaluated at farm level in order to assess their feasibility, taking into account input requirements, contributions to self-sufficiency in food and long-term soil fertility, and the availability of labor. In this study, we defined four scenarios to explore consequences of changes in current farming systems for eight typical farms in the region; the first two scenarios comprised redressing current imbalances in crop nutrition and organic matter (OM) supply, respectively, and the last two scenarios explored high fertilizer input and animal husbandry. Farms responded in different ways to the various options depending on available land, current soil quality, current cropping systems and presence of livestock. Improvements in crop nutrition based on mineral fertilizers increased family income but only had substantial effects on soil OM (SOM) balances when fertilizer rates were double the amount currently subsidized. Addition of organic fertilizers resulted in positive effects on SOM balance, but with often strong trade-offs with family income due to costs of acquisition, transport and application. Animals played an important role in increasing SOM balances, but had relatively little effect on improving family income. The results demonstrated that improvements in family income and SOM balance at farm scale were feasible but that without more fundamental system changes trade-offs between short-term yield increases and longer-term soil fertility increases should be expected. The results highlight the need for policies that take into account farm-specific differences in crop and livestock intensification opportunities.
... Agronomists have worked extensively and published on this issue ( e.g. Hengsdijk and Van Ittersum, 2003) and have proposed hierarchical methods to systematically derive and assess alternative activities. Yet, because of the discontinuity of the production functions, the theoretically infinite number of options ( crops x general x water x nutrient x pest and disease x conservation management options) and the difficulty of assessing the alternatives, their (partial) inclusion in future studies keeps an arbitrary element. ...
In this contribution we first present a methodology for integrated assessment of agricultural systems (SEAMLESS Integrated Framework), illustrate its application in an integrated assessment of high commodity prices and then discuss its flexibility and limitations. From there we take a broader view and reflect on key scientific and empirical questions with respect to the development of research tools for the integrated assessment of agricultural systems.
... Land use and land cover change are key factors contributing to ecological risk, and many ecological factors are sensitive to these processes (Metzger et al., 2006;Reidsma et al., 2006;Niroula and Thapa, 2005). A variety of methods and techniques have been used to assess the impact of land use change (Lindeijer, 2000) with the overall goal of standardizing agricultural engineering practices to ensure long-term sustainability of land use (Hengsdijk and Ittersum, 2003). Among these methods, some employ multidisciplinary approaches in assessing the economic, societal, and environmental effects of land consolidation (Huylenbroeck et al., 1996;Coelho et al., 2001;Crecente et al., 2002). ...
The purpose of this study is to identify and classify the ecological risks in land consolidation, and to develop a framework of the theory and method to assess the change of ecological risk degree before and after land consolidation. Environmental impacts and ecological risks of land consolidation have recently drawn much attention, and there are two opposing viewpoints to assess these impacts and risks in the academia of China. Both viewpoints result from the bias of assessment anticipation. Land consolidation includes four main engineering aspects in China, and ecological succession from start of land consolidation to ecosystem stabilization should pass three phases. Different ecological impacts and risks of land consolidation rise from different phases of ecological successions. According to the climax theory of ecology, we developed a framework of the ecological risk assessment based on the anticipation of ecosystem stabilization (ERABAES) for land consolidation. We applied analytical hierarchical processing (AHP) method to the data resources from the land consolidation project in Southern China to allocate weightings to the indices of ecological risk (ER), and to set up an integrated index system for the ecological risk identification. This integrated index system encompasses the ecological risks with three factors (water, soil and biology) and 14 indices. The results of the project show: (1) The ER is reduced from 58.02 to 28.8 after land consolidation and the degree of ecological risk is down from Degree III to Degree IV. (2) According to the element analysis, the water ER is reduced from 21.53 to 6.16, its contribution to reduce the ecological risk is 53%; the reduced ERs of soil and biology are respectively 12.79 and 1.06, their contribution of ecological risk reduce is lower than water.
... It has been designed for simulating a wide range of farmers' systems and addressing a great variety of policy questions. FSSIM follows a primal-based approach, where technology is explicitly represented (Louhichi et al., 1999), using engineering production coefficients generated from agronomic theory and biophysical models (Hengsdijk and Van Ittersum, 2003 ). These engineering coefficients constitute the essential linkage between the biophysical and economic models. ...
Bio-economic models can be used to assess the impact of policy and environmental measures through economic and environmental indicators. Focusing on agricultural systems, farmers' decisions in terms of cropping systems and the associated crop management at field scale are essential in such studies. The objective of this paper is to present a study using a bio-economic model to assess the impact of the Nitrate Directive in the Midi-Pyrenees region (France) by analyzing, at the farm scale, farm income and three environmental indicators: nitrate leaching, erosion and water consumption. Two scenarios, the 2003 CAP reform (baseline scenario) and the Nitrate Directive (policy scenario), with a 2013 time horizon, were developed and compared for three representative arable farm types in the Midi-Pyrenees region. Different types of data characterizing the biophysical context in the region (soil, climate), the current cropping systems (rotation, crop management) and farm resources (irrigated land, labor) were collected to calibrate and run the models. Results showed that the implementation of the Nitrate Directive may not affect farm income. However, significant modifications to cropping systems and crop allocation to soil types were simulated. Contrary to expectations, nitrogen leaching at the farm scale did not change. Overall water consumption increased and soil erosion decreased due mainly to a modification in cropping patterns and management by soil type. This study provides an example of unanticipated effects of policy and trade-offs between environmental issues.
... Current activities are largely based on surveys and databases that monitor the agricultural activities of sampled farms across the EU-25. Alternative activities are systematically generated through a set of tools within FSSIM-AM using agronomic knowledge rules (Dogliotti et al., 2003;Hengsdijk and van Ittersum, 2003). FSSIM-AM can be linked to APES to assess productivity and externalities. ...
Agricultural systems continuously evolve and are forced to change as a result of a range of global and local driving forces. Agricultural technologies and agricultural, environmental and rural development policies are increasingly designed to contribute to the sustainability of agricultural systems and to enhance contributions of agricultural systems to sustainable development at large. The effectiveness and efficiency of such policies and technological developments in realizing desired contributions could be greatly enhanced if the quality of their ex-ante assessments were improved. Four key challenges and requirements to make research tools more useful for integrated assessment in the European Union were defined in interactions between scientists and the European Commission (EC), i.e., overcoming the gap between micro–macro level analysis, the bias in integrated assessments towards either economic or environmental issues, the poor re-use of models and hindrances in technical linkage of models. Tools for integrated assessment must have multi-scale capabilities and preferably be generic and flexible such that they can deal with a broad variety of policy questions. At the same time, to be useful for scientists, the framework must facilitate state-of-the-art science both on aspects of the agricultural systems and on integration. This paper presents the rationale, design and illustration of a component-based framework for agricultural systems (SEAMLESS Integrated Framework) to assess, ex-ante, agricultural and agri-environmental policies and technologies across a range of scales, from field–farm to region and European Union, as well as some global interactions. We have opted for a framework to link individual model and data components and a software infrastructure that allows a flexible (re-)use and linkage of components. The paper outlines the software infrastructure, indicators and model and data components. The illustrative example assesses effects of a trade liberalisation proposal on EU’s agriculture and indicates how SEAMLESS addresses the four identified challenges for integrated assessment tools, i.e., linking micro and macro analysis, assessing economic, environmental, social and institutional indicators, (re-)using standalone model components for field, farm and market analysis and their conceptual and technical linkage.
... This method allows establishment of the tradeoffs between the different goals. This approach of 'agroecological engineering' is described formally by Hengsdijk and van Ittersum, (2003). The dairy farming model has been described in detail by van de Ven (1996). ...
Instead of continuously adapting current dairy farming systems according to the ruling legal instruments, exploring strategic development options for the farming system with a focus on the final environmental goals may provide better perspectives for farm continuation. To identify promising options, the dairy farming model was developed. The model describes options of different intensities for producing feed in the field, for processing or buying feed and for converting feed into milk. The combinations of different intensities result in different types of income levels, different nutrient emissions into the ecosystem and different abilities to manage the landscape. The model reconciles economic objectives (maximizing income per ha) with ecological objectives (minimizing nutrient leakages and maximizing landscape values). The multiple-objective model is in turn fed by other models, such as technical coefficient generators for grass, maize and fodder beets. The dairy farming model is applied to assess the type of farming systems that meet environmental policy objectives and analyse the perspectives of dairy farming on sandy soils in the Netherlands. It is shown that many different dairy farming systems are possible meeting the environmental goals (maximum 34 kg N leached, 30 kg N volatilized and a P surplus below 2.2 kg ha−1), with a range in environmental and economic performance. The scenario selected depends on the preference of the stakeholder. General characteristics are low N application rates on grazed grassland, associated with the restriction on nitrate leaching, animals housed in low-emission stables, associated with the restriction on ammonia volatilization, and a substantial part of the concentrates produced in the region, associated with the restriction on P surplus. Production and utilization of hay is an option to reduce N excretion by the animals. Regional or on-farm concentrate production is economically only attractive if land is in surplus under pressure of environmental goals.
... These coefficients are generated using the survey data described in Section 2.3. and TechnoGIN (Ponsioen et al., 2003(Ponsioen et al., , 2006, a generic expert tool for integrating different types of information on crop production (Hengsdijk and Van Ittersum, 2003). The survey data are used to assess yields, labour and capital inputs, the use of biocides, and seed costs. ...
Economic growth in China’s agricultural sector lags behind growth in industry and services, creating an ever widening rural–urban income gap. Development of the non-agricultural sectors offers new opportunities for farmers in China’s more advanced provinces such as Zhejiang. Increased income in the urban sector creates markets for new products, and migrating farmers rent their land to those staying. Until now, the prevailing rice-based systems have been managed mainly using manual labour and animal traction, but the larger farms resulting from migration may facilitate, or even require mechanization. In this study, we use a simulation model of the farm household to analyse the effects of increasing farm size and the transition from rice to vegetable production, while also studying the effects of mechanization.Our results show that at the present scale of farming, the dual government objectives of increasing rural incomes and increasing rice production are clearly conflicting. Farmers can generate incomes comparable to non-farm wages, but only when they switch completely to production of more remunerative crops, such as vegetables. At larger farm sizes, however, labour constraints inhibit farmers from specialization in non-rice crops, and rising per capita incomes and increasing rice production go hand in hand. Mechanization is necessary to allow substantial increases in farm size.
... These technical coefficients are discrete estimates stating the amount of inputs needed to achieve certain outputs and the associated economic and environmental effects. Technical coefficient generators (TCGs) (Hengsdijk and van Ittersum, 2003) can then be defined as algorithms to translate data information into coefficients that represent the input and output relationships for each discrete activity. The biophysical and economic rules that determine the transformation of inputs into outputs for a given activity are generally non-linear (Ten Berge et al., 2000). ...
Bio-economic farm models (BEFMs) are developed to enable assessment of policy changes and technological innovations, for specific categories of farming systems. A rapidly growing number of research projects is using these models and there is increasing interest for application. The paper critically reviews past publications and applications of BEFMs on their strengths and weaknesses in assessing technological innovation and policy changes for farmers and policy makers and highlights key issues that require more attention in the use and methodology of BEFMs. A BEFM is defined as a model that links formulations describing farmers’ resource management decisions to formulations that represent current and alternative production possibilities in terms of required inputs to achieve certain outputs, both yield and environmental effects. Mechanistic BEFMs are based on available theory and knowledge of farm processes and these were the focus of our study. Forty-eight applications of mechanistic BEFMs were reviewed as to their incorporation of farmer decision making and agricultural activities, comprehensiveness, model evaluation, and transferability. A clear description of end-use of the BEFM, agricultural activities, model equations and model evaluation are identified as good practices and a research agenda is proposed including the following issues: 1. development of a thorough and consistent procedure for model evaluation; 2. better understanding and modelling of farmer decision making and possible effects of the social milieu; 3. inclusion of several economic and environmental aspects of farming including multifunctionality and 4. development of a generic, modular and easily transferable BEFM.
... TCGs integrate and synthesize different databases and models or their results, and enable quantification of cropping systems in a transparent and reproducible way. Using intelligent interfaces, relevant inputs and outputs of engineered cropping systems characterized by their design criteria can be jointly calculated and analyzed (Hengsdijk and Van Ittersum, 2003). The TCG used in this study (for details, refer to Hengsdijk et al., 1996) was adapted from an integrated framework for analysing sustainable land use, developed by a Dutch-West African research project. ...
Agricultural production in the semi-arid agro-ecosystems of the Sahel centres on cereal staple crops and pastoralism with increasing crop–livestock integration. Animals mobilize soil fertility through manure production, graze crop by-products, and transfer nutrients from distant pastures to cropped areas. Yet in these systems various interacting factors, i.e. climate variability, poor soil fertility, poverty, and institutional constraints limit the capacity of agriculture to keep pace with the growing needs of an increasing human population.
... FSSIM-MP requires quantitative information on input-output relationships of agricultural activities. Computer programs, often referred to as Technical Coefficient Generators (TCGs), have been developed to quantify a large number of activities (Hengsdijk and Van Ittersum, 2003). Most of these TCGs are targeted at specific regions or production systems. ...
Developing countries are extremely vulnerable to climate change, due to their strong economic dependency on rain-fed agriculture. Land-use policies can offer a less vulnerable future by design and application of relevant mitigation and/or adaptation strategies. Effectiveness of such strategies depends on local conditions. Therefore, hotspot regions are defined, where specific issues related to agriculture will be assessed. Mitigation strategies in East Africa in general and Ethiopia in particular include reforestation, while adaptation covers aspects such as crop diversification and water use efficiency. An analytical framework is developed in which a science-policy interface is the main focus. On one hand policy-makers and stakeholders can be involved in such a framework for policy design, while scientists on the other hand deliver data and modeling tools. The model chain in the framework is integrated by an evaluation step where policy options are compared for efficiency on several development targets. The framework will be tested in 2010 in hotspot regions in East Africa.
... When detailed crop management data is available, for example through the detailed survey (Section 4.2), the conversion of the simple management data through expert rules in the SMT is not needed. Technical coefficient generators (TCGs) (Hengsdijk and van Ittersum, 2003) are algorithms to process data and information into technical coefficients directly usable by a mathematical programming model (e.g. FSSIM-MP) and cropping systems models (e.g. ...
SEAMLESS (System for Environmental and Agricultural Modelling; Linking European Science and Society) integrated project, EU 6th Framework Programme, contract no. 010036-2
... These coefficients are generated using the survey data described in Section 2.3. and TechnoGIN (Ponsioen et al., 2003(Ponsioen et al., , 2006, a generic expert tool for integrating different types of information on crop production (Hengsdijk and Van Ittersum, 2003). The survey data are used to assess yields, labour and capital inputs, the use of biocides, and seed costs. ...
Economic growth in Chinas agricultural sector lags behind growth in industry and services, creating an ever widening rural-urban income gap. Yet growth beyond the farm offers new opportunities for farmers in Chinas more advanced provinces: markets for new crops and increasing farm size. At present, the dual government objectives of increasing rural incomes and increasing rice production are clearly in conflict. Farmers can obtain incomes comparable to non-farm wages only when they stop rice cultivation and switch to more profitable crops. Otherwise, mechanization is necessary to allow large enough increases in farm size to raise household income and maintain national rice production levels.
... Sommige van deze studies hebben betrekking op het heden, maar ook kunnen er studies worden gedaan naar uitdagingen voor de toekomst, waarbij vervolgens wordt gekeken wat de problemen zijn die opgelost dienen te worden om tot die situaties te komen (foresightstudies en backcasting) . Dit kan bijvoorbeeld worden gedaan door middel van een brainstorm van experts of belanghebbenden in een bepaalde sector (zie bijvoorbeeld van der Meulen, 1999;Rutten, 1999;De Wilt et al, 2001;Schwab et al., 2003), of door middel van modelstudies die trachten het potentieel van een bepaalde regio naar boven te halen (zie bijvoorbeeld Hengsdijk, 2003;Van Ittersum, 1998 (Chambers et al., 1989;Okali et al., 1994;Van Veldhuizen et al., 1997;Van de Fliert en Braun, 2002;Oudshoorn, 2003). ...
... Sustainable farming systems require development of agricultural farming systems based not only on economic performance, but also based on contribution to objectives in areas such as environment, health and well-being, rural scenery and nature (OECD, 2000). An agro-ecological systems approach can help to design sustainable farming systems, and agro-ecological engineering approaches aimed at design and exploration of alternative land use systems at various scales may support the identification of appropriate land use options (Hengsdijk and van Ittersum, 2003). Aim of the project is to investigate how current systems can be redesigned to meet goals of resource use efficiency, resource conservation and acceptable economic return. ...
Economic benefits by increased market integration stimulated changes in traditional agricultural land use by smallholders in Costa Chica, a remote part of Guerrero State, Mexico, resulting in more input-dependent, simplified production systems, but also soil degradation and declining yields. This situation has resulted in a spiral of unsustainability. Nevertheless, there is a group of farmers that are conscious about these problems, and they are interested in agro ecological innovations addressed to improve the current cropping systems by means of compost/animal manure, crop rotations including legumes and cover crops, and a transition to organic production. This contribution reports early results of participatory agronomy aimed at searching for ways to revert the degradation of the resource base.
It is of great significance to research the changing patterns of current regional cultivated land and explore its impact on grain productivity. "3S" technology can not only improve precision, speed and efficiency of data collection, but also obtain and manage various kinds of agricultural resource information with spatial attributes effectively, and monitor and assess the cultivated land dynamic change. This research is innovative in such aspects as research content, method and so on. Firstly, taking Northeast China as a study area, with the help of "3S" technology and on the basis of spatial and temporal land resource data, agricultural statistics data and considering the natural and socio-economic factors, this paper analyzed the impact of cultivated land change on the grain production capacity within this region in terms of cultivated land quantity, cultivated land quality, crop structure etc. Secondly, since the soil nutrient data obtained from field survey in 2005 differ greatly from the data obtained at the time of the second soil survey in the 1980s on the aspect of sample position, quantity, time and soil analytical method, this paper did not carry out comparative research with the cultivated land quality of the period of the second soil survey, but analyzed the spatial distribution of the change of the cultivated land quality caused by the change of cultivated land quantity. Thirdly, considering cultivated land quality is the comprehensive reflection of different properties of cultivated land, the elements of cultivated land quality include the natural factors and social-economic factors mainly. And the natural resources, cultural structure and social-economic conditions among different regions may vary greatly, thus the natural and social-economic factors will exert different effects on grain production in different regions, and this proves that it is important to manage cultivated land resources based on regionalization. In recent years, the peasants have increased the input amount on the cultivated land, such as fertilizer and mulch film, which resulted in different effects on cultivated land quality in Northeast China. Under the above-mentioned background, this paper analyzed cultivated land quality information in the concerned region. The method was to explore natural quality grading and utilizing quality grading on cultivated land respectively through natural quality grading and utilizing quality grading indicator systems. And then we divided the whole region into high-yield cultivated land, medium-yield cultivated land and low-yield cultivated land based on per unit area grain yield, and the correlation was analyzed between natural quality grading of land and per unit area grain yield as well as between utilizing quality grading of land and grain yield per unit area through GIS method. In a word, this paper can provide some help to sustainable utilization and management of cultivated land resource in the study and offer useful reference for the similar research in other regions.
The increased interest in Integrated Assessment (IA) of agricultural systems reflects the growing complexity of policy objectives and corresponding impacts related to this sector. The paper contemplates on the status of quantitative tools for IA in agriculture, drawing on recent European experiences from the development and application of large-scale integrated modelling systems which are both multi-dimensional/disciplinary and covering multiple spatial scales. Specific challenges arise from the numerous roles of agriculture with societal relevance, the heterogeneity of farms and farming systems across a geographical region and the multitude of environmental impacts of interest associated with agricultural production. Conceptual differences between typical bio-physical and economic models as well as deficiencies regarding validation and uncertainty analysis require continued efforts to improve the tools.
Regional ecological risk assessment (RERA) can be defined as a risk assessment deals at a spatial that contains multiple habitats with multiple sources of multiple stressors affecting multiple endpoints and the characteristics of the landscape affect the risk estimate. Therefore, establishment RERA index system was quite complicate and being a hotspot in resent research. This paper discussed the history of RERA, reviewing RERA study in China and the proper site selection in Hulunbeier presenting RERA index system. An index system was set up based on the principle: Comparability, Available and Relevant. This index system developed by regarding the risk of land use change, industrial pollution and social economy as well as adopted ecosystem services, landscape and support system for regional risk assessment of degraded land (SYRIADE) methods.
Engineering achievements have improved the quality of human life, provided creature comforts, and expanded the human domain to unprecedented levels. When enjoying all these achievements, human beings are coming to realize that the more invasion of the nature, the more environmental problems. Under the context of sustainable development, it is certain that effective Engineering Management calls for an ecological concept. The basic claim of this paper is that Engineering Management should be based on Ecological Engineering, which is an essential requirement of effective Engineering Management. At the same time, Ecological Engineering shall serve as the base of Engineering Management, which is commanded by the characteristics of Ecological Engineering. To date, there are only scattered studies focused on Engineering Management using the ecological concept. Moreover, there is no systematic concept of Ecological Engineering based Engineering Management (EMEE). In this paper, a thorough review of EMEE is presented. Our goals are to clarify this concept, promote this promising thought, summarize past research, and identify issues for future research to create impacts on the practice of Engineering Management.
The Helpdesk of European Evaluation Network for Rural Development supported by a group of external experts has prepared a Working Paper on ”Capturing the impacts of Leader and measures to improve the Quality of life (QoL) in rural areas”. The working paper provides methodological support for evaluators, managing authorities and other interested parties. The main evaluation challenges include: assessing the “double scope” of Leader (it is both a process and generates impacts); the need to adequately define what is QoL in the context of Rural Development Programmes (RDPs); tackling the qualitative nature of the effects; identifying contributions from small-scale interventions; and the fact that the EU’s Common Monitoring and Evaluation Framework (CMEF) requires assessment of impacts ultimately at programme level. The working paper is targeted primarily at practitioners involved in the evaluation of the current RDPs (2007-2013). It proposes a framework of reference which provides a conceptual model in order to assess Quality of Life around four dimensions – environment, socio-culture, economy and governance.
With the project planning and design of land consolidation, an index system for the ecological risks assessment is set up based on the identification of the ecological risks with 14 indexes and three factors as water, soil and biology. The index standard is studied out, and the weighting allocation of the index system is workout by AHP. The integrated index of ecological evaluation (ER) is established. The results of the trial use of the suggested index system indicate that, (1) The ER is reduced 28.94 after land consolidation, and the ecological risk is down from level III to level IV; (2) By the element analysis, the water ER is reduced from 21.53 to 6.16, its contribution to the ecological risk is 53%; The ERs of soil and biology are respectively 12.97 and 0.79, their contribution of ecological risk are lower than water.
Studies aimed at assessing agriculture in the context of climate change, natural resource use and food security are only useful if they account for the effect of changes in agricultural management and technological innovation. The challenge is, however, that the number of possible alternative management options and technological changes is enormous which hinders a transparent analysis. This paper presents an approach based on Data Envelopment Analysis (DEA) to identify a manageable set of representative alternative activities out of a large set of possible alternatives. The smaller set is superior in terms of different indicators that are relevant from an economic, environmental or policy point of view. The selected, superior activities can then be further analysed in a farm or natural resource use model. To demonstrate the usefulness of the method we applied it to a range of possibilities that arise if cattle manure is used instead of fertilizers in arable farms in Flevoland (the Netherlands), where due to manure surplus, arable farmers can apply manure at low costs.
The aim of this study was to evaluate the sustainability of farm irrigation systems in the Cébalat district in northern Tunisia. It addressed the challenging topic of sustainable agriculture through a bio-economic approach linking a biophysical model to an economic optimisation model. A crop growth simulation model (CropSyst) was used to build a database to determine the relationships between agricultural practices, crop yields and environmental effects (salt accumulation in soil and leaching of nitrates) in a context of high climatic variability. The database was then fed into a recursive stochastic model set for a 10-year plan that allowed analysing the effects of cropping patterns on farm income, salt accumulation and nitrate leaching. We assumed that the long-term sustainability of soil productivity might be in conflict with farm profitability in the short-term. Assuming a discount rate of 10% (for the base scenario), the model closely reproduced the current system and allowed to predict the degradation of soil quality due to long-term salt accumulation. The results showed that there was more accumulation of salt in the soil for the base scenario than for the alternative scenario (discount rate of 0%). This result was induced by applying a higher quantity of water per hectare for the alternative as compared to a base scenario. The results also showed that nitrogen leaching is very low for the two discount rates and all climate scenarios. In conclusion, the results show that the difference in farm income between the alternative and base scenarios increases over time to attain 45% after 10 years.
The need to take into account sustainability in agricultural resource management is now universally admitted. While the term
“sustainability” can mean different things to different people, it always involves a consideration of the future. From an
economic point of view, sustainability can be defined as an improvement of the performance of a system so as not to exhaust
the basic natural resources on which its future performance depends (Pearce et al. 1990). This definition emphasizes the importance
of preserving the natural resource base.
This research is innovative in such aspects as research content, method and so on. Authors took Northeast China as study area, with the help from "3S" technology and based on spatial and temporal land resource data, agricultural statistics data and considering the natural and socio-economic factors. And, this paper analyzed the impact of cultivated land change on the grain production capacity within this region in terms of cultivated land quantity, cultivated land quality, crop structure etc. The natural resources, cultural structure and social-economic conditions among different regions may have great difference, the natural and social-economic factors will have different influence on the grain-production in different regions, and this proves that it is important to manage cultivated land resources based on regionalization. In the last few years, the peasants have increased the input amount on the cultivated land, such as the fertilizer and the plastic film, this caused the different influence on the cultivated land quality in the Northeast China. Under the above-mentioned background, this paper analyzed the cultivated land quality information in the Northeast region. The method was to explore the natural quality grading and utilizing quality grading on cultivated land respectively through the natural quality grading indicators and utilizing quality grading indicators system. Then we divided the whole region into high-yield cultivated land, medium-yield cultivated land and low-yield cultivated land based on grain yield per unit, correlation was analyzed between natural quality grading of land and grain yield per unit area, also between utilizing quality grading of land and grain yield per unit area through GIS method. In a word, this paper can provide help to sustainable utilization and management of cultivated land resource in this area, and give the useful method for the similar research.
This paper presents SysNet, a systems research network in South and South-east Asia, established to develop and evaluate methodologies for enhancing formulation of strategic land use policies. SysNet adopted theory and concepts from both natural and social science approaches. Multiple goal linear programming was used to integrate information on a broad range of alternative land use systems, resource availability and policy objectives, to reveal possibilities and limitations of agricultural resource use and trade-offs between policy objectives. The methodology was developed and applied in and with a network of researchers and stakeholders, for four case study areas in India, Malaysia, the Philippines and Vietnam. An application is presented for Haryana State (India), to illustrate the methodology and its components, as well as the type of questions that can be explored and subsequently discussed with stakeholders. We discuss lessons learnt on how to communicate LUPAS to stakeholders in interactive settings, with details for the Kedah-Perlis case region in Malaysia.
Remediation action is critical for the management of polychlorinated biphenyl (PCB) contaminated sites. Dozens of remediation technologies developed internationally could be divided in two general categories incineration and non-incineration. In this paper, life cycle assessment (LCA) was carried out to study the environmental impacts of these two kinds of remediation technologies in selected PCB contaminated sites, where Infrared High Temperature Incineration (IHTI) and Base Catalyzed Decomposition (BCD) were selected as representatives of incineration and non-incineration. A combined midpoint/damage approach was adopted by using SimaPro 7.2 and IMPACTA2002+ to assess the human toxicity, ecotoxicity, climate change impact, and resource consumption from the five subsystems of IHTI and BCD technologies, respectively. It was found that the major environmental impacts through the whole lifecycle arose from energy consumption in both IHTI and BCD processes. For IHTI, primary and secondary combustion subsystem contributes more than 50% of midpoint impacts concerning with carcinogens, respiratory inorganics, respiratory organics, terrestrial ecotoxity, terrestrial acidification/eutrophication and global warming. In BCD process, the rotary kiln reactor subsystem presents the highest contribution to almost all the midpoint impacts including global warming, non-renewable energy, non-carcinogens, terrestrial ecotoxity and respiratory inorganics. In the view of midpoint impacts, the characterization values for global warming from IHTI and BCD were about 432.35 and 38.5 kg CO(2)-eq per ton PCB-containing soils, respectively. LCA results showed that the single score of BCD environmental impact was 1468.97 Pt while IHTI's score is 2785.15 Pt, which indicates BCD potentially has a lower environmental impact than IHTI technology in the PCB contaminated soil remediation process.
Ecological engineering, the practice of designing, creating or manipulating, and monitoring ecosystems, is applied for a variety of purposes benefiting both human society and the natural environment, often integratively. While there are basic principles that help practitioners in the development and implementation process, at this time there is no comprehensive theory that guides the design of ecosystems. In order for such theory to be developed, extensive knowledge about the interactions between ecosystem constitution and comportment, and ways to analyze and integrate this knowledge, are needed. Consequently, the ability to qualitatively and quantitatively evaluate large datasets in a multivariate fashion is required. Thus, the objective of this project was to investigate the use of case-based reasoning as a method of gathering and analyzing large sets of ecological data not only for prediction but for engineering purposes, a previously untested application. To maximize the number of cases to be analyzed without limiting the inputs to only known systems described in the literature, a virtual ecosystem and simulation platform was created. Simulation outputs and values for applied measures were compiled into a case base for use with a case-based reasoner to attempt to predict the results of several additional randomly created virtual ecosystems. Actual results were compared to the predicted results. The accuracy of the predictions made by the case-based reasoner varied, but they were more than 75% accurate 83.3% of the time. An initial attempt was made to apply this approach to "engineering" ecosystems for specified performance levels within the virtual ecosystem framework. While the targeted values of persistence were not obtained, the "engineered" virtual ecosystems were more persistent overall than the randomly created systems, with an average ratio of 0.40527 surviving species to initial species versus an average persistence of 0.20750 for the random systems. This is indicative of the potential of this novel approach for data analysis in ecological engineering. Le génie des écosystèmes, soit la pratique de concevoir, créer ou manipuler, et faire la suivi des écosystèmes, s'applique, souvent de manière intégrée, au bénéfice de la société humaine et de l'environnement naturel. Quoiqu'il y ait des principes de base pouvant servir à de tels ingénieurs dans le développement et mise en oeuvre de tels écosystèmes, présentement il n'existe aucune théorie compréhensive pouvant guider la conception d'écosystèmes artificiels. Afin qu'une telle théorie soit énoncée, il nous faut acquérir des connaissances approfondies quant aux interactions existant entre les constituants et le comportement de l'écosystème, et quant à comment procéder dans l'analyse et l'intégration de ces connaissances. Il devient donc nécessaire de pouvoir faire l'évaluation qualitative et quantitative de grands ensembles de données par des méthodes d'analyse multivariable. L'objectif de ce projet fut donc d'étudier l'utilisation d'une méthodologie de raisonnement par cas pour recueillir et faire l'analyse de grands ensembles de données écologiques, autant pour servir à des prédictions qu'à des fins d'ingénierie, une application préalablement inévalué. Afin de maximiser le nombre de cas pouvant être analysés sans limiter les données d'entrée à celles décrites dans les ouvrages scientifiques, un écosystème virtuel et une plateforme de simulation furent conçus. Les données de sortie des simulations et les valeurs pour les mesures mises en oeuvre furent compilés dans une base de cas conçue pour servir d'intrant à un raisonneur par cas qui servirait à prédire les résultats de plusieurs écosystèmes virtuels supplémentaires, chacun créé de façon aléatoire. Ces résultats furent comparés aux valeurs prédites. L'exactitude des prédictions du raisonneur par cas varia, mais, 83.3% du temps, dépassa 75%. Un essai préliminaire fut entrepris pour mettre en oeuvre cette démarche d'ingénierie d'écosystème pour des niveaux de performance précis dans le cadre d'un écosystème virtuel. Quoique les niveaux de persistance visés ne furent pas atteints, les écosystèmes virtuels "façonnés" furent, dans l'ensemble, plus persistants que ceux bâtis de façon aléatoire, avec un rapport moyen des espèces ayant survécu aux espèces initiales de 0.40527, comparé à 0.20750 pour les écosystèmes aléatoires. Cela met en évidence le potentiel de cette nouvelle démarche pour l'analyse de données en génie des écosystèmes.
WOFOST version 7.1 is a computer model that simulates the growth and production of annual field crops. All the run options are operational through a graphical user interface named WOFOST Control Center version 1.5 (WCC). WCC facilitates selecting the production level, and input data sets on crop, soil, weather, crop calendar, hydrological field conditions, soil fertility parameters and the output options. The files with crop, soil and weather data are explained, as well as the run files and the output files. A general overview is given of the development and the applications of the model. Its underlying concepts are discussed briefly.
IntroductionTraditional agricultural production systems in Sub-Saharan Africa were based on transfer of nutrients by grazing animals from rangeland to cropland, combined with fallowing. These systems are under increasing pressure as a result of rapid population increase. In most of the semi-arid and sub-humid zones, the area of rangeland, required to maintain cropland productivity, is not available anymore. The associated continuous decline in soil productivity induces risks of food shortage and irreversible soil degradation, and every effort should be made to avoid further deterioration of the resource base. Integration of crops and livestock and the associated intensified nutrient cycling are often advocated as desirable developments towards sustainable land use. Performance of these integrated systems hinges on the management of crop residues and manure, which represent the main source of organic matter and nutrients for animal and soil.The objective of the present study was to analyse the consequences of alternative management techniques of crop residues, from a sustainable crop-livestock farming perspective in the North Soudanian zone of Burkina Faso. The specific objectives were: (1) To establish response curves describing the effect of (varying degrees of) selective consumption of crop residues (as single feeds and in various combinations) on animal production; (2) to evaluate the effect of alternative systems of feeding crop residues on labour requirements and household income; (3) to evaluate the effect of alternative systems of feeding residues on crop production and on organic matter, nitrogen and phosphorus balances at farm level; (4) to determine the trade-offs among various objectives associated with alternative crop residue management techniques.The approachThe potential contribution of crop residues to ruminant feeding in the four agro-ecological zones distinguished in Burkina Faso was estimated, applying the Java Program developed at the Animal Production Systems Group of Wageningen University (Chapter 2). The number of animals that can be fed and their production were estimated on the basis of availability and quality (digestibility and N content) of crop residues (cereal stovers and legume haulms).Feeding trials were carried out with sheep to determine the relationships between the quantities of crop residues offered on the one hand, and intake and digestibility of ingested material on the other hand. In Chapter 3, the effect of selective consumption on intake and digestibility of sorghum, cowpea and groundnut residues is described. Two additional feeding trials were conducted as a basis for optimising the use of cowpea and groundnut haulms as supplement to sorghum stover (Chapter 4). The models used for analysis of the data allow description of the combined effects of animal selectivity for the better fractions of cereal stover, and of supplementation, on intake and digestibility of ingested material. Results of the feeding trials complemented by literature data served as the basis to derive iso-production curves. Based on the isoquant concept, least-cost rations were derived for a range of combinations of cereal stovers and supplements.The possibilities for optimal utilisation of crop residue at farm level was analysed using a linear programming technique. To quantify the relevant household resources, constraints and objectives, farm surveys were conducted (Chapter 5). The above-mentioned iso-production curves served as the basis for quantification of the technical coefficients for animal feeding activities, while for crop activities various models from the literature were applied to the region under consideration. A Multiple Goal Linear Programming (MGLP) model (referred to as HOREB, Household level Optimal crop REsidue allocation in Burkina Faso) was developed to determine the effect of various crop residue management techniques on farm productivity, economics and sustainability, in terms of balanced organic matter, nitrogen and phosphorus budgets (Chapters 6 and 7). The main results are discussed in Chapter 8, with special attention for the contribution of crop residues to sustainable land use in Sub-Saharan Africa.Contribution of crop residues to ruminant feeding at regional levelOn the basis of current crop production, 54 and 98 % of the current ruminant population can potentially be maintained during the dry season in the Sub-Sahelian and North-Soudanian zones, respectively. There might even be scope for increasing the contribution of crop residues to animal production in these areas, by increasing production of legume haulms and allowing selective use of stover leaves.It may also be profitable to take advantage of the capacity of animals to use feeds selectively by excess feeding. This requires, however, collection techniques and conservation structures that minimise the reduction in nutritive value of the scarce highest quality residues (legume haulms). The objective of rearing animals, either maximisation of animal production or maintaining the maximum number of animals, determines the most suitable feeding techniques. Maximising animal production is associated with inclusion of smaller quantities of cereal stovers in the ration and with a smaller number of animals kept. Maintaining the maximum number of animals allows the use of more cereal stovers and results in higher manure availability for arable fields, and so may contribute to maintaining cropland productivity.Optimising crop residue use at animal levelResults of the feeding trials show that unsupplemented sorghum stover can hardly be used for animal production, due to its low intake and digestibility, and its low protein content. Even maintenance can only be reached if selective consumption of leaves is allowed; In our trials, sheep reached the maintenance level only when 87 g OM kg -0.75d -1was offered, of which only 53 % was eaten. Offering cowpea and groundnut haulms, maintenance can be achieved with 36 and 39 g OM kg -0.75d -1, respectively. These results illustrate, that when coarse, low quality forages are fed alone, selection is not a waste, but a prerequisite for animal production and even for maintaining animals. Excess feeding of sorghum stover (allowing selective consumption of leaves), significantly reduced the quantity of supplement (cowpea and groundnut haulms) needed to reach a desired level of intake of digestible organic matter (IDOM). Up to 54 g OM kg -0.75d -1of groundnut haulms was needed for 1.4 times maintenance (33.6 g DOM kg -0.75d -1) when animals ingested 90 % of the sorghum stover, but only 29 g OM kg -0.75d -1was needed, when animals were allowed to eat only 50 % of the sorghum stover offered.Optimising crop residue use at farm levelThe results of farm surveys indicate that availability of a donkey cart for transport allowed storage of significantly more high quality crop residues (cowpea haulms). The stored residues served as animal feed (100 % for legume haulms and 70 % for cereal stovers), the remainder being used as building material, source of fuel for cooking, etc. Crop residues remaining in the fields are commonly grazed and only the non-edible parts serve as soil amendment. Factors such as relationships between farmers and herdsmen, location of fields, herd composition and production system, and available means of transportation determine the quantities of crop residues collected.On a farm (6.2 ha available land) with 210 md available labour per month, where crop residues are not collected for stall feeding in the dry season and no capital is available to buy fertiliser, a maximum of 3.2 t staple food can be produced in normal (average rainfall) years. When the household does collect crop residues for sheep stall feeding and aims at maximum gross margin, attainable staple production hardly changes, when no external inputs are used. The household could produce 4.5 t staple, when maximising total gross margin under balanced OM and nutrient budgets, provided sufficient working capital to buy external inputs is available. Model results suggest that reduction of the current crop area by 0.5 to 1.2 ha (depending on the restrictions imposed on nutrients budgets) is necessary to allow integration of sheep stall feeding, because of the required labour for residues collection. Integration of sheep stall feeding could then contribute to restriction of the expansion of the crop area without compromising households food security.Availability of labour for crop residue collection and storage is the major limiting factor for the integration of crops and stall feeding of sheep. Labour availability dictates, in combination with the objectives of animal keeping, the selection among the different feeding techniques. Chopping, requiring substantial investment in labour, is selected when the farmer aims at maximising availability of manure, security or savings, for which a maximum number of animals is fed at maintenance. Treatment with urea requires, in addition to chopping, working capital to buy urea. This option is hardly ever selected because of the combined limitations of labour, capital and low remuneration. At the current urea price and labour availability conditions, excess feeding is the best method of feeding in all scenarios.Maximising crop gross margin is always associated with soil mining; 20-27 % of calculated farm gross margin originates from soil mining, if soil nutrients and organic matter are valued at inorganic fertiliser and stover prices, respectively. From 200- 344 kg OM, 15-21 kg N and 1.5-1.8 kg P per ha are lost annually from the system when animals are not stall fed (extensive feeding system). When crop residues are collected for stall feeding of sheep and the farmer aims at maximum total gross margin, annual losses are 175-192 kg OM, 12-15 kg N and 1.1-1.2 kg P. The results of these analyses clearly illustrate that intensive management of crop residues in integrated crop-livestock farming systems cannot maintain soil nutrient status. Nutrients from external sources are necessary, either in the form of concentrate or fertiliser. Moreover, maximum gross margin per manday of labour invested in sheep feeding activities is 0.20 kF, which is much lower than the actual labour wages in the area. Hence, if off-farm employment is available, stall-feeding of sheep is not an economically attractive alternative. Economic profitability can be improved if capital availability allows utilisation of concentrate, i.e. 0.28 kF extra gross margin can be attained per kF invested in cotton seed cake. Potentially, attainable gross margin from sheep feeding is 182 kF per household, when crop residues would be optimally collected (80 % of the cereal stovers and 86 % of the legume haulms produced).Conclusions
Integration of crops and livestock is often considered as a step towards sustainable agricultural production, because of the associated intensified organic matter and nutrients cycling through intensive crop residue management. The main advantage of the integration of livestock and crops is the added value derived from crop residues (especially those of legumes) in terms of animal products and income. Intensive management of crop residues in integrated crop-livestock farming appears a means of guaranteeing subsistence in an environment characterised by growing competition for organic matter and nutrients between animals and soil. Sustainable production, at regional level, can only be triggered by external inputs. However, the current price ratios of fertiliser and grains are hardly conducive to fertiliser utilisation. The prospects for sustainable crop-livestock production are intimately linked to the price of external inputs and to the low availability of working capital. Investment in concentrate is remunerative, but lack of cash is a serious constraint for their acquisition. Improved credit facilities for farmers may stimulate intensification of livestock production and thereby increase nutrient availability for cropland, and hence sustainable land use practices.
The first premise of this book is that farmers need access to options for improving their situation. In agricultural terms, these options might be manage ment alternatives or different crops to grow, that can stabilize or increase household income, that reduce soil degradation and dependence on off-farm inputs, or that exploit local market opportunities. Farmers need a facilitating environment, in which affordable credit is available if needed, in which policies are conducive to judicious management of natural resources, and in which costs and prices of production are stable. Another key ingredient of this facilitating environment is information: an understanding of which options are viable, how these operate at the farm level, and what their impact may be on the things that farmers perceive as being important. The second premise is that systems analysis and simulation have an impor tant role to play in fostering this understanding of options, traditional field experimentation being time-consuming and costly. This book summarizes the activities of the International Benchmark Sites Network for Agrotechnology Transfer (IBSNAT) project, an international initiative funded by the United States Agency for International Development (USAID). IBSNAT was an attempt to demonstrate the effectiveness of understanding options through systems analysis and simulation for the ultimate benefit of farm households in the tropics and subtropics. The idea for the book was first suggested at one of the last IBSNAT group meetings held at the University of Hawaii in 1993.
Mixed farming systems have potential agronomic, environmental and socio-economic advantages over specialized farming systems. This paper attempts to quantify these advantages for the Dutch province Flevoland. A mixed farming system at regional lever is characterized by intensive co-operation between two or more specialized farms, each producing crop or animal products. To test the hypothesis that such a mixed farming system might improve sustainability of agriculture in Flevoland, nutrient balances, labour requirements and labour income were quantified for a specialized arable farm, a specialized dairy farm and both combined into a mixed farming system, exchanging land, labour and machinery. Scope for reduced biocide use in the mixed farming system was assessed in a qualitative way. In the mixed farming system labour income per ha was 25% higher. Seventy percent of this increase could be explained through higher yields per ha of the profitable crops ware potato (Solanum tuberosum L.) and sugar beet (Beta vulgaris L.). The remaining 30% resulted from lower costs, mainly through a better utilization of available labour. Differences between the combined nutrient balance of both specialized farms and that of the mixed farming system were small. Indications of reduced biocide use in the mixed farming system could not be found. It was concluded that in a mixed farming system it is possible to realize a higher income without increasing environmental pollution. Key factor is the ratio between animal and arable production, determining the extent to which crop rotations can be widened and the relative amounts of slurry that can be applied to grassland.
A mathematical model was developed to describe C and N cycling in different types of soil, e.g. clay and sandy soils. Transformation rates were described by first-order kinetics. The fraction of active soil organic matter was assumed to be affected by the extent of physical protection within the soil, as was the soil microbial biomass. The mineralization rate in fine-textured soils is lower than in coarse-textured soils; in fine-textured soils a larger proportion of the soil organic matter may be physically protected. The availability of organic materials as a substrate for microorganisms is not only determined by their chemical composition, but also by their spatial distribution in the soil. -from Authors
GLASOD project ISRIC ISSS FAO ITC Staring Centre
The dynamics and spatial pattern of a weed population are analysed with a model that takes explicit account of the spatial position of individual weeds. In this model weeds are held at a low density in an environment with homogeneous abiotic conditions. Maintaining low weed densities requires a weed removal rate close to the critical removal rate that marks the transition from possible survival to certain extinction of the population. At these low densities, the spatial pattern of weeds and the local population dynamics obey scaling laws. These scaling laws and the value of the scaling exponents are robust to changes in the model. Based on this analysis, weeds are expected to occur in scale-invariant spatial patterns. In a field observation, the spatial distribution of the weed Galium aparine is found to be scale-invariant.
This paper describes a rain-event driven, process-oriented simulation model, DNDC, for the evolution of nitrous oxide (N2O), carbon dioxide (CO2), and dinitrogen (N2) from agricultural soils. The model consists of three submodels: thermal-hydraulic, decomposition, and denitrification. Basic climate data drive the model to produce dynamic soil temperature and moisture profiles and shifts of aerobic-anaerobic conditions. Additional input data include soil texture and biochemical properties as well as agricultural practices. Between rainfall events the decomposition of organic matter and other oxidation reactions (including nitrification) dominate, and the levels of total organic carbon, soluble carbon, and nitrate change continuously. During rainfall events, denitrification dominates and produces N2O and N2. Daily emissions of N2O and N2 are computed during each rainfall event and cumulative emissions of the gases are determined by including nitrification N2O emissions as well. Sensitivity analyses reveal that rainfall patterns strongly influence N2O emissions from soils but that soluble carbon and nitrite can be limiting factors for N2O evolution during denitrification. During a year sensitivity simulation, variations in temperature, precipitation, organic C, clay content, and pH had significant effects on denitrification rates and N2O emissions. The responses of DNDC to changes of external parameters are consistent with field and experimental results reported in the literature.
About 8,000 plot‐years of soil‐loss and related data assembled from 21 states were analyzed to evaluate influences of vegetal growth, crop sequence, tillage practices, fertility, and residue management on erosion of soil by rainfall. Specific‐crop data were grouped according to relatively homogeneous intervals such as the respective rough fallow, seedbed, establishment, growing crop, and residue periods. For each such period, measured soil losses under specific combinations of crop sequence and management were compared with corresponding losses from bare fallow. Not only canopy protection, but the residual effects of prior cropping and management as well, differed significantly for the respective crop‐stage periods. Soil losses for each crop‐stage period under various sequences and management levels are presented in tabular form as percentages of losses from fallow under identical rainfall. The table was designed for use with rainfall erosion index maps and monthly distribution curves computed from localized rainfall records as discussed in “A Rainfall Erosion Index for a Universal Soil‐Loss Equation” (Soil Sci. Soc. Am. Proc. 23:246–249. 1959). Combined with the erosion index and other factors comprising the soil‐loss equation, the tabulated values will help to provide valuable guides for conservation farm planning adapted to the local rainfall pattern.
Beginning in 1981, a mathematical model called the erosion-productivity
impact calculator model (EPIC) was developed to determine the relation
between soil erosion and soil productivity throughout the U.S.A. By 1985
the model was ready for use in the RCA (1977 Soil and Water Resources
Conservation Act) analysis. Between 15 000 and 20 000 EPIC simulations
of 100 years each were performed as part of the 1985 RCA analysis. After
the RCA analysis, model refinement and development continued and EPIC
has been applied to a number of agricultural management problems. For
example, EPIC is capable of dealing with decisions involving drainage,
irrigation, water yield, erosion (wind and water), weather, fertilizer
and lime application, pest control, planting dates, tillage, and crop
residue management. Example applications include: (i) 1988 drought
assessment; (ii) soil loss tolerance tool; (iii) Australian sugarcane
model (AUSCANE); (iv) pine tree growth simulator; (v) global climate
change analysis, and (vi) farm level planning.
Current production systems for flower bulbs in the Netherlands employ considerable quantities of pesticides and nutrients per unit area. In 1993, an association of growers and environmentalists set out to design new farming systems that meet environmental objectives in addition to economic objectives. To support the design process, an explorative study was carried out to bring together the fragmented agronomic information and to assess agro-technical options for sustainable flower bulb production with a time horizon of 10 to 15 years. Crop and inter-crop management systems representing the agro-technical components of sustainability at the farm level, were generated with a computer model by systematically varying four system characteristics, three of which represented strategic and tactical aspects of crop protection. Subjective components, one economic and two environmental objectives and various socio-economic constraints, were identified in interaction with the stakeholders. Interactive multiple goal linear programming was used to optimize the objectives at the farm level and determine the exchange value of the economic objective in terms of the environmental objectives. Calculations were carried out for two reference farm types. The results revealed that the negative impact of environment-oriented production systems on farm gross margin is importantly mitigated by strategic choices at the farm level, such as renting land and allowing a soil health improving crop, even though of low gross margin, into the rotation. In contrast, the a priori attention of the growers was focused on improving tactical pest and nutrient management at the crop level, the effect of which on farm gross margin is constrained by the strategic choices. Sensitivity analyses highlighted the need for more insight into the ecology of soil-borne growth reducing factors and their effect on crop yield. The paper describes the approach used, reports results and discusses the usefulness of the approach for the stakeholders and for disciplinary crop protection research.
This paper describes a formalized approach to identify and engineer future-oriented land use systems. Such land use systems can be used to explore options for strategic decision making with respect to land use policy and to do ex-ante assessment of land use alternatives to be further tested or developed in experimental settings. The so-called goal-oriented approach consists of three steps: (1) goal-oriented identification and design of land use systems; (2) quantification of biophysical production possibilities; and (3) defining the optimal mix of inputs, i.e. the production technique, required to realize production possibilities. The goal-oriented identification and design depends on the land-related objectives of a system under study, whereas plant, animal and environmental characteristics determine biophysical production possibilities. Characteristics of the production technique determine the realization of production possibilities. General guidelines are given to structure the specification and number of alternatives to be explored and to apply agro-ecological principles required for quantification of future-oriented land use systems. Concepts of the approach are illustrated with data from the northern Atlantic zone of Costa Rica and the Sudano–Sahelian zone of Mali. Finally, suggestions are given for the application of the approach at spatial and temporal scales exceeding the field level and time horizon of 1 year.
The (semi-) arid area of West Africa is characterized by erratic rainfall that causes highly variable performances of cropping systems. This creates difficulties in strategic decision-making based on future-oriented production systems. In this paper, the degree of variation in inputs and outputs of future-oriented millet (Pennisetum glaucum L.) systems is quantified using a dynamic crop growth simulation model and a static technical coefficient generator. To determine inputs and outputs of future-oriented millet systems under (semi-) arid conditions, the target-oriented approach was operationalized for low-yielding conditions. Economic yield, N-loss and labor requirement were used as benchmarks for outputs and inputs of future-oriented land use systems. Weather data for 31 year characterize two sites in the (semi-) arid zone of Mali, while for each site two soil types with distinct properties were considered. In all four physical environments, inputs and outputs of millet systems have coefficients of variation (CV) exceeding 50%.
In this paper, a pedigree of the crop growth simulation models by the ‘School of de Wit’ is presented. The origins and philosophy of this school are traced from de Wit's classical publication on modelling photosynthesis of leaf canopies in 1965. It is shown how changing research goals and priorities over the years have resulted in the evolution of a pedigree of models that are similar in philosophy but differ in level of complexity, the processes addressed and their functionality. In the beginning, modelling was motivated by the quest for scientific insight and the wish to quantify and integrate biophysical processes to explain the observed variation in crop growth. Later, the emphasis of, and funding for, agricultural research shifted towards putting acquired insights to practical and operational use. Model development became led by a demand for tactical and strategic decision support, yield forecasting, land zonation and explorative scenario studies. Modelling developments for different production situations are illustrated using the models the authors consider most important, i.e. BACROS, SUCROS, WOFOST, MACROS and LINTUL, but reference is also made to other models. Finally, comments are made about the usefulness and applicability of these models after nearly 30 years of development, and some future courses of action are suggested.
This paper describes two generic so-called technical coefficient generators, PASTOR (Pasture and Animal System Technical coefficient generatOR) and LUCTOR (Land Use Crop Technical coefficient generatOR), that quantify land use systems in terms of inputs and outputs based on the integration of systems-analytical knowledge, standard agronomic and animal husbandry data and expert knowledge. PASTOR quantifies livestock systems while LUCTOR is geared towards cropping systems. Main inputs quantified include costs, labour requirements, fertiliser use and application of crop protection agents. Outputs are production and a number of associated environmental indicators. Although both PASTOR and LUCTOR were developed to generate input data for land use models, they are also useful as stand-alone tools to explore the technical efficiency of land use systems, to perform cost-benefit analyses and to quantify the trade-off among socio-economic, agronomic and environmental indicators at the field level. PASTOR and LUCTOR are illustrated with data from the Northern Atlantic zone in Costa Rica. Tools such as PASTOR and LUCTOR integrate different types of knowledge, including non-documented knowledge from field experts and make that knowledge transparent and open to critical review and discussion by others.
To support the different phases of a policy making process aimed at changing land use, distinct types of land use studies are required. This paper focuses on exploratory land use studies and their role in the phase of formulating strategic policy objectives. Exploratory land use studies contribute to a transparent discussion on policy objectives by showing ultimate technical possibilities and consequences of imposing different priorities to agro-technical, food security, socio-economic and environmental objectives. A methodology is presented in which science-driven technical information is confronted with value-driven objectives under given values of exogenous variables (e.g. regarding population growth and requirements for agricultural produce). Land use scenarios are generated showing consequences of different priorities for objectives by using natural resources and technical possibilities in different ways. Applications of such an approach are given for the global, regional and farm level, each addressing specific questions and target groups. The paper focuses on the type of results these studies produce and their role in the societal and political debate on strategic land use policy and planning. It is concluded that if exploratory land use studies are carried out in true interaction with target groups, they may well contribute to the debate and learning on sustainable land use options and a purposeful identification of effective policy instruments in a next phase of the policy making process.
One of the main goals of the International Consortium for Agricultural Systems Applications (ICASA) is to advance the development and application of compatible and complementary models, data and other systems analysis tools. To help reach that goal, it will adopt and recommend modular approaches that facilitate more systematic model development, documentation, maintenance, and sharing. In this paper, we present criteria and guidelines for modules that will enable them to be plugged into existing models to replace an existing component or to add a new one with minimal changes. This will make it possible to accept contributions from a wide group of modellers with specialities in different disciplines. Two approaches to modular model development have emerged from different research groups in ICASA. One approach was developed by extending the programming methods used in the Fortran Simulation Environment developed in The Netherlands. This method is being used in revisions of some of the Decision Support Systems for Agrotechnology Transfer crop models. A simple example of this approach is given in which a plant growth module is linked with a soil water balance module to create a crop model that simulates growth and yield for a uniform area. The second approach has been evolving within the Agricultural Production Systems Research Unit group in Australia. This approach, implemented in software called Agricultural Production Systems Simulator, consists of plug-in/pull-out modules and an infrastructure for inter-module communication. The two approaches have important similarities, but also differ in implementation details. In both cases, avoiding reliance on any particular programming language has been an important design criterion. By comparing features of both approaches, we have started to develop a set of recommendations for module design that will lead to a ‘toolkit’ of modules that can be shared throughout the ICASA network.
A framework is developed for crop yield simulation that accounts for uncertainty in soil and management input parameters. The framework consists of three steps: (1) the calculation of ‘standard yield’ using estimated soil and management parameters that are supposed to be representative for the land unit under consideration; (2) sensitivity analysis on the soil and management parameters; and (3) the calculation of yield probability from probability distributions for the soil and management parameters through Monte Carlo simulation. The results of sensitivity analysis are useful in setting up cost- and time-efficient measurement strategies. When a large number of actual soil and management measurements have been made, Monte Carlo simulation results in actual yield variability in the land unit. The developed framework is illustrated for rainfed upland rice on a loamy soil in The Philippines, using the MACROS crop growth model. The uncertainty in the simulated yield was large: there was 90% probability that simulated yield was between 0.6 and 1.65 times the simulated standard yield in average years. In general, accurate yield prediction will be conditional on the availability of accurate soil and management parameters.
This article points out the kinds of problems agriculture is facing, outlines and structures agricultural quality components and defined aims for them, discusses the shortcomings of organic farming, proposes some important research areas and presents an outlook. The quality components are a type of checklist of those factors that we should be aware of concerning protection of the environment, production of healthy food and the practice of good ethics. These components can be integrated into the general aims of sustainable agriculture. Many European and other countries focus on organic farming as a solution, but this approach is dangerous because it does not necessarily lead to a better environment or better food products. Concerning future agricultural research, the following issues are highly important: precision agriculture, low leaching cropping systems, management of soil biological processes and maximum recirculation. Finally, the article discusses some issues of future agriculture such as intensity, nutrient imbalances caused by regional farm specialisation, and the development of an agricultural quality assessment system.
A generic methodology is presented for exploration of sustainable land use options at the regional level by quantifying trade-offs between socio-economic and biophysical sustainability objectives. The methodology is called SOLUS (Sustainable Options for Land USe), and was developed over a ten year period of investigation in the Northern Atlantic Zone of Costa Rica. SOLUS includes a linear programming model, technical coefficient generators for livestock and cropping activities and a geographic information system. The linear programming model maximizes regional economic surplus subject to a flexible number of resource and sustainability constraints. Economic sustainability indicators are economic surplus and labor employment, and biophysical ones include soil N, P and K balances, pesticide use and its environmental impact, nutrient losses and a proxy for trace gas emissions. The capabilities of the methodology are illustrated for the Northern Atlantic Zone of Costa Rica. Though ample scope exists for reducing environmental effects and introducing sustainable production systems separately, pursuing both objectives simultaneously, considerably reduces economic surplus and agricultural employment. Agricultural area can be decreased and forested area increased without severely affecting the regional economic surplus.
Sustainability of tropical pastures has various economic and biophysical dimensions and is affected by species composition, age and management. The sustainability of pastures in cattle ranching systems was analyzed in terms of economic viability, soil nitrogen stock change, CO2 loss/sequestration, N2O and NO emissions, pollution by herbicides, and nitrogen leaching loss, for a case study in the Northern Atlantic Zone of Costa Rica. Development scenarios were explored for the next 25 years based on degradation and yield decline of current pastures, and on possible introduction of grass–legumes and fertilized improved grass species. With degradation of current pastures, gross margin, soil nitrogen stock, nitrogen leaching and N2O and NO emissions are simulated to decrease in time, whereas CO2 emission and herbicide use increase. With the introduction of grass–legumes or fertilized grasses, the reverse takes place. The conversion of degraded pasture to grass–legumes or fertilized grasses is calculated to lead to a sequestration of CO2 of up to 50 ton C ha−1, which might be a potential mechanism in mitigating the greenhouse effect. Quantitative, exploratory studies point out the often conflicting nature of different dimensions of sustainability and show possible pathways of sustainable development.
Historically, the motivations for decision-makers to understand the dynamics and behavior of agricultural systems were the requirements to assess and predict future food production and supply. More recently, however, it has become evident that in addition to being units of food production, agricultural systems may also either damage or provide ecological goods and social welfare. Thus, the need for enhanced environmental protection also provides a motivation for understanding the dynamics of farming systems. Historically, models aimed at simulating one component of the farm system, be it either the food production or ecological systems, have tended to ignore the social component of the farm system. This omission, which has been related partly to reductionist scientific processes and partly to the difficulty of modeling social systems, is unfortunate because the responses of people to their economic and social environment is what ultimately determines the other outputs of agricultural systems. In this paper, the progress made in modeling the individual production, ecological and social components of agricultural systems is reviewed, and modeling frameworks for their future integration are examined.
Cereals farming in the cercle of Nara, N.W. Mali, is described. Production is constrained by the availability of labour for weeding, which is in turn constrained by the supply of the wage good—food. Casual labour sales, migration and changes to family structure adjust labour use to the supply of food. This hypothesis is supported by cross-sectional statistical analysis. The process's regressive distributive tendencies are mitigated by social reallocation mechanisms. It is concluded that so-called subsistence production systems can appear markedly capitalist when food is considered as a means of production.
Intensive agriculture in The Netherlands has a price in the form of environmental degradation and the diminution of nature and landscape values. A reorientation of farming is needed to find a new balance between economic goals and rural employment, and care for clean water and air, animal well-being, safe food, and the preservation of soil, landscape and biodiversity. The search for farm systems that meet such multiple goals requires a systematic combination of (a) agrotechnical, agroecological and agroeconomic knowledge, with (b) the stakeholders’ joint agreement on normative objectives, to arrive at conceptual new designs followed by (c) empirical work to test, adapt and refine these under real commercial farming conditions. In this paper explorative modelling at the whole farm level is presented as a method that effectively integrates component knowledge at crop or animal level, and outlines the consequences of particular choices on scientific grounds. This enables quantitative consideration of a broad spectrum of alternative farming systems, including very innovative and risky ones, before empirical work starts. It thus contributes to a transparent learning and development process needed to arrive at farm concepts acceptable to both entrepreneurs and society. Three case studies are presented to illustrate the method: dairy farming on sandy soils; highly intensified flower bulb industry in sensitive areas in the western Netherlands; and integrated arable farming. Trade-offs between economic and environmental objectives were assessed in all three cases, as well as virtual farm configurations that best satisfy specified priority settings of objectives. In two of the three cases the mutual reinforcement and true integration of modelling and on-farm empirical research appeared difficult, but for obvious reasons. Only in the flower bulb case was the explorative approach utilized to its full potential by involving a broad platform of stakeholders. The other two case studies lacked such formalised platforms and their impact remained limited. Three critical success factors for explorative modelling are identified: to cover a well-differentiated spectrum of possible production technologies; early timing of modelling work relative to empirical farm prototyping; and involvement of stakeholders throughout.
In agriculture, water and nitrogen are two critical resources for growing a crop. However, their management cannot be analyzed independently of weather, soil characteristics, field hydrology, crop characteristics, crop rotation, and management factors. This paper describes the water, nitrogen, and crop growth components of CropSyst, a comprehensive cropping systems simulation model, and provides preliminary verification of these components. The water budget of the model properly describes crop water use. Predicted nitrogen contents throughout the soil profile did not exactly match the measured values from leaching experiments, but they did follow the general trends of the data. The agreement between simulated and observed biomass and yield of corn, winter wheat and spring wheat grown in two locations with a total of 77 data points was good as shown by several statistical indicators. Based on this preliminary validation, CropSyst appears promising as a tool to analyze management practices for water and nitrogen. Additional validation of model components, including a wide range of crops and conditions, should be conducted in the future.
APSIM (Agricultural Production Systems Simulator) is a software system which allows (a) models of crop and pasture production, residue decomposition, soil water and nutrient flow, and erosion to be readily re-configured to simulate various production systems and (b) soil and crop management to be dynamically simulated using conditional rules. A key innovation is change from a core concept of a crop responding to resource supplies to that of a soil responding to weather, management and crops. While this achieves a sound logical structure for improved simulation of soil management and long-term change in the soil resource, it does so without loss of sensitivity in simulating crop yields. This concept is implemented using a program structure in which all modules (e.g. growth of specific crops, soil water, soil N, erosion) communicate with each other only by messages passed via a central ‘engine’. Using a standard interface design, this design enables easy removal, replacement, or exchange of modules without disruption to the operation of the system. Simulation of crop sequences and multiple crops are achieved by managing connection of crop growth modules to the engine.A shell of software tools has been developed within a WINDOWS environment which includes user-installed editor, linker, compiler, testbed generator, graphics, database and version control software. While the engine and modules are coded in FORTRAN, the Shell is in C++. The resulting product is one in which the functions are coded in the language most familiar to the developers of scientific modules but provides many of the features of object oriented programming. The Shell is written to be aware of UNIX operating systems and be capable of using the processor on UNIX workstations.
Serious soil loss, food insecurity, population pressure, and low income of the rural population are interrelated, and consequently result in a spiral of unsustainability in the Loess Plateau, China. This thesis takes Ansai County in the Loess Plateau of China as a case study, to explore strategic land use options that may break the unsustainability spiral and meet goals of regional development. A systems analysis approach has been applied, in which fragmented and empirical information of the biophysical and agronomic conditions is integrated with well-adapted production ecological principles and other knowledge sources.With respect to the land use problems and regional development objectives, alternative production activities (systems) have been identified and quantified using a 'target-oriented approach' and the concept of 'best technical means', and based on information obtained from a quantitative land evaluation (based on the EPIC model), experimental data, literature and expert knowledge. Production activities have been quantified for cropping, fruit, grassland and firewood production systems, and animal husbandry. Production techniques emphasize soil conservation, productivity, use efficiency or low emission of chemicals. The quantified production activities, resource constraints, and socio-economic and environmental objectives have been incorporated into a multiple goal linear programming model that is used to optimize land use allocation, evaluate trade-offs among objectives and evaluate policy scenarios.The results reveal that the goals of food security and soil conservation in Ansai can be easily achieved from a biophysical and agro-technical point of view. Current slope cultivation and the resulting serious soil loss can be greatly reduced, while still guaranteeing food security for the rural population (in 2020). The soil loss control is, to a large extent, in line with the goals of increasing crop productivity and labor productivity (net agricultural return per laborer). In the long term, terracing and crop rotations with alfalfa could be the best options for soil conservation and also for agricultural production. The large rural labor force can be used for terrace construction. Alfalfa can fix nitrogen, and thus greatly reduce the demand for fertilizer N, and also improve soil fertility.The large rural population and the lack of off-farm employment opportunities could be the most important factor affecting rural development in Ansai. This is evident from the trade-off results, i.e., increasing the total employment in agriculture leads to an apparent adverse effect on many other objectives. However, there is a potential for maintaining high agricultural employment at a reasonable income level. The current low net return due to the very limited external inputs and poor crop and soil management can be substantially improved by efficient resource use and appropriate inputs.This research work contributes to the understanding of regional problems and agricultural development potentials. The results show agro-technical possibilities for breaking the spiral of unsustainability in this very fragile and poorly endowed region. Soil conservation, food security, employment and income for the rural population can be greatly enhanced by appropriate land use and agro-techniques. To promote actual development towards the identified options, appropriate policy measures aimed at improving the land tenure system and controlling population growth must be developed and implemented. The explored land use options enable a much more targeted policy development. In addition, the study can contribute to the formulation of a research agenda for research at field, crop and animal level.
This thesis provides a framework for integrated nutrient management in agricultural land use systems, with particular reference to its impact on productivity, fertilizer use efficiency, and sustainability in well-delimited tracts of land (agro-ecological units), characterized by a specific set of soil and climatic properties. Most of the research was conducted in Kenya, but methodology and results can be applied to any tropical region.Quantitative assessments are made of the nitrogen, phosphorus and potassium balance in the root zone of the arable land in sub-Saharan Africa. Land use systems are characterized by nutrient inputs (mineral fertilizer, manure, atmospheric deposition, biological nitrogen fixation, sedimentation) and nutrient outputs (removal of harvested crop parts and residues, leaching, denitrification, erosion), and the balance between the two. It is shown that outputs exceed inputs all over the continent. As scale-inherent simplifications were inevitable, a more detailed study is presented for the Kisii District in Kenya, with similar results. The alarming figures call for agronomic and policy interventions in the soil nutrient balance. A scaleneutral decision- support model of this nature is described, in which scenarios for improved nutrient management are worked out.Mineral fertilizers are, with the present abolishment of subsidies in many African countries, increasingly expensive, and it is evident that they must be used efficiently. With this in mind, a network of 70 researcher-managed, but farm-based factorial fertilizer trials was established in rainfed agricultural Kenya. The trial sites were chosen such that they represent wider ranges of similar environments. As such, the results form a basis for fertilizer recommendations that are not just crop-specific, but also specific for agro- ecological units. The site selection procedure is demonstrated, based on a profound scrutiny of soil and climate maps in Kenya, and followed by results of four years study on the response of maize to fertilizers and manure in three agro-ecological units.The above approach leads to recommendations which apply to a district scale, but do not account for spatial variability between and within individual farmers' fields. Field-level heterogeneity, however, affected some trials as it was beyond the researcher's control. Two examples are dealt with in detail, i.e. (i) bypass flow and associated nitrogen leaching in a cracking clay soil, and (ii) the spotty emergence of the parasitic weed Striga hermonthica.As the establishment and maintenance of a trial network is costly and timeconsuming, computer models are increasingly used as an alternative. The QUantitative Evaluation of the Fertility of Tropical Soils (QUEFTS) model describes relations between (i) soil chemical parameters, (ii) potential supply of N, P and K from soils and fertilizers, (iii) actual uptake of N, P and K by maize, and (iv) maize grain yield. Characteristic features of the model are the inclusion of all macronutrients, acknowledging interactions between them, and the low input requirements enabling agronomists in tropical environments to test the model. The four steps of QUEFTS are calibrated with input data from fertilizer trials in different agro- ecological units. A complete run of the modified version shows a high correlation between measured and calculated yield, but although new relations are found, the basic structure and theoretical concepts of the original QUEFTS still stand.
Long-term explorations serve to widen the perspectives of decision makers. Biophysical and technical possibilities and constraints are confronted with the valuedriven objectives of stakeholders in Multiple Goal Linear Programming (MGLP) models. Two methodological aspects of long-term explorations are elaborated in this thesis: uncertainty in agro-ecological coefficients and temporal aspects of land use. The effects of these aspects on generated land use scenarios are studied using data from the Northern Atlantic Zone of Costa Rica (NAZ).Uncertainties in agro-ecological coefficients concerning nutrients and biocides were quantified. Only uncertainties caused by lack of knowledge of underlying biophysical processes or lack of data for quantification were considered. "Average", "pessimistic" and "optimistic" estimations of coefficients were generated, based on different perceptions of the influence of environmental factors. The estimations of the coefficients for various production activities are strongly correlated owing to the assumption of "best technical means" (i.e. inputs are used with the highest technical efficiency according to available knowledge and techniques). These coefficients were used in the single-period MGLP-model that was constructed for the NAZ. With the help of sensitivity analyses the effect of uncertainties on land use scenarios was determined for five tentative policy views, representing different perceptions of sustainability. It is concluded that, in long-term explorations, uncertainties in agroecological coefficients strongly affect the objective function values. However, they hardly affect the optimal land use allocation, because the ranking of production activities for the agro-ecological coefficients hardly changes when including uncertainties.In long-term explorations the following temporal aspects are relevant: 1. Growth and ageing of crops and livestock, 2. Fluctuations in coefficients caused by variation in weather conditions, 3. Interactions in time. After an inventory of possibilities and limitations to describe these temporal aspects in LP-models, a multi-period version of the single-period model was constructed. In theory, all temporal aspects can be described in multi-period MGLP-models, although location-bound temporal interactions pose serious problems owing to the limitations of the LP-technique. In most cases, the relevant types of temporal aspects can also be included in singleperiod models with the help of predefined cropping sequences and additional coefficients and variables. It is discussed, that in long-term explorations the use of a multi-period model may have added value only if large differences in coefficients between periods and growth stages occur and if strong bounds are put on fluctuations over periods.Based on the land use scenarios generated with the single-period and multi-period model it is concluded that there is considerable scope for policy in the NAZ. The differences between land use scenarios for the five policy views are large, regardless of the effects of the uncertainties in agro-ecological coefficients and the explicit inclusion of temporal aspects. By revealing the consequences and possibilities under particular land use objectives and constraints, this long-term exploration may help to structure and organize the discussion on desires for the future in the NAZ.
Technical options in crop and animal husbandry to reduce soil nutrient mining and other forms of natural resource degradation in the Sudano-Sahelian zone should be economically attractive, if they are to be adopted. A model is presented in which agronomic and economic information and goals are combined to explore possibilities for agro-ecologically sustainable and economically viable land use in three different climatic regions in Mali and for a situation of non-degraded soils. The time frame of the study is to the year 2010. For each region, an agro-ecologically sustainable land use system (a combination of crop, livestock and pasture production systems) that maximizes income of the agricultural sector and satisfies self sufficiency targets is identified. Special attention is given to the use of chemical fertilizer in crop activities. It is shown that use of chemical fertilizer is an important element of sustainable and economically viable land use, especially in higher rainfall regions. Population size has a marked effect on optimal land use systems in the regions, but self sufficiency is not endangered even if the population is 50% higher than estimated for 2010. It is argued that results should not be used to simulate the actual situation or future developments, but to define priorities for agricultural development in the Sudano-Sahelian region.
Mixed farming systems have potential agronomic, environmental and socio-economic advantages over specialized farming systems. This paper attempts to quantify these advantages for the Dutch province Flevoland. A mixed farming system at regional level is characterized by intensive cooperation between two or more specialized farms, each producing crop or animal products. To test the hypothesis that such a mixed farming system might improve sustainability of agriculture in Flevoland, nutrient balances, labour requirements and labour income were quantified for a specialized arable farm, a specialized dairy farm and both combined into a mixed farming system, exchanging land, labour and machinery. Scope for reduced biocide use in the mixed farming system was assessed in a qualitative way. In the mixed farming system, labour income per ha was 25% higher. Seventy percent of this increase could be explained through higher yields per ha of the profitable crops ware potato (Solanum tuberosum) and sugar beet (Beta vulgaris). The remaining 30% resulted from lower costs, mainly through a better utilization of available labour. Differences between the combined nutrient balance of both specialized farms and that of the mixed farming system were small. Indications of reduced biocide use in the mixed farming system could not be found. It was concluded that in a mixed farming system, it is possible to realize a higher income without increasing environmental pollution. Key factor is the ratio between animal and arable production, determining the extent to which crop rotations can be widened and the relative amounts of slurry that can be applied to grassland.
The .Systems Research Network for Ecoregional Land Use Planning in Support of Natural Resource Management in Tropical Asia (SysNet). was financed under the Ecoregional Fund, administered by the International Service for National Agricultural Research (ISNAR). The objective of the project was to develop and evaluate methodologies and tools for land use analysis, and apply them at the subnational scale to support agricultural and environmental policy formulation. In the framework of this project, the land use planning and analysis system LUPAS was developed. In this volume, the highlights of the project period between October 1999 and June 2000 are illustrated through presentations of the results of the most recent scenario analyses for the four case study regions (Haryana State, India; Kedah- Perlis Region, Malaysia; Can Tho Province, Vietnam; and Ilocos Norte Province, Philippines) . Subsequently, special attention is paid to the development and description of the user interface and interaction with the stakeholders in the case study areas. The volume concludes with a brief outline of the most important challenges ahead.
Definitions and concepts of production ecology are presented as a basis for development of alternative production technologies characterized by their input-output combinations. With these concepts the relative importance of several growth factors and inputs is investigated to explain actual yield levels and resource-use efficiencies. Differences between potential and actual levels are analyzed to open ways for improved production technologies. The basis of the analysis is knowledge of basic physical, chemical, physiological and ecological processes at soil, field and crop level. New production technologies and their input-output combinations can be used in studies aimed at the exploration of options for sustainable agricultural production systems and land use. The concepts allow a systematic analysis and quantification of input-output combinations and clearly discriminate between bio-physical possibilities and socio-economic constraints and objectives. They help in defining objectives and means for agricultural production and land use, and may be valuable as aids to communication between various disciplines involved in studying the possibility and feasibility of future production technologies and land use options. The concepts production level, physical environment, target-oriented approach, production technique, production activity, and production orientation are applied to identify new technologies and production systems at various levels of scale, each requiring different types of information. In this paper some examples of applications are given at field, farm and at regional level.
Simulations of N2O and CO2 emissions from soils were conducted with a rain-event driven, process-oriented model (DNDC) of nitrogen and carbon cycling processes in soils. The magnitude and trends of simulated N2O (or N2O + N2) and CO2 emissions were consistent with the results obtained in field experiments. The successful simulation of these emissions from the range of soil types examined demonstrates that the DNDC will be a useful tool for the study of linkages among climate, soil-atmosphere interactions, land use, and trace gas fluxes.
This discussion paper is the first in a series of papers prepared as part of IFPRI's 2020 Vision initiative, which seeks to develop an international consensus on how to meet future world food needs while reducing poverty and protecting the environment. It shows that poverty and environmental degradation in the developing world are inextricably linked with inadequate agricultural intensification. Increased investment in agriculture and poverty alleviation are essential for preventing further resource degradation and for meeting future food needs in a sustainable manner.