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Simulated production of five major crops grown in Halaba District compared to 2014. Crops growing on soils with mean surveyed characteristics (table 2). Rainfall and air temperature used in steady state and post El Niño simulations were obtained from records for 2014. Actual weather data were used for years when El Niño effects were seen in 2015 and 2016.
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The use of limited organic resources to build resilience to drought in semi-arid regions was investigated using systems modelling. The study focussed on Halaba in Ethiopia, drawing on biophysical and socioeconomic data obtained from a survey of farms before, during and after the 2015/16 El Niño event. Using a simplified weather dataset to remove no...
Citations
... Degradation of soils in Ethiopia is also attributed to the reduced use of organic amendments due to competing uses of crop residues and animal manures for fuel (Amede et al., 2001;Nyssen et al., 2015;Wassie, 2020). This is exacerbated by climate change and extreme weather events, such as the recent El Niño effect, which significantly increased the risk of soil erosion, and soil carbon and nutrient losses (Smith et al., 2019). ...
... Thus, despite the relatively short duration of the study of two years, we were able to show that mixed fertilizer applications affected soil parameters, which are also crucial to build soil resistance for drought. In particular, higher organic C contents ensure a more sustainable and resilient crop production based on higher water-holding capacity of the soil (Derbile 2013;Smith et al. 2019). Surprisingly, most of the soil nutrients did not significantly increase, when the fertilizers were applied. ...
The combined application of organic and mineral fertilizers is an appropriate agronomic measure and is particularly important for smallholders who have limited access to mineral fertilizers. However, fertilizer recommendations in terms of crop nutritional value and nutrient efficiency strongly vary in dependence of site-specific conditions. In this study, seven different ratios of bio-waste compost (comp) and mineral fertilizers (MF), consisting of nitrogen (N), phosphorus (P), and sulfur (S), were tested in a two-year field experiment on a Nitisol soil in order to assess their effects on nutritionally important minerals in maize (Zea mays, L. Bako-hybrid) grains as well as the nutrient use efficiency. The application of fertilizers corresponded to an N supply of about 100 kg ha −1 , whereby the application of only MF (100 MF) was gradually replaced by compost. Compared to 100 MF the treatments with 40 to 70% of N supply given with compost had a higher concentration of most grain minerals. The most pronounced elevations were found for Fe (570 vs. 304 mg kg-1) and Mn (70.1 vs. 36.3 mg kg-1) when 50% of the N was given with compost in comparison to the 100 MF treatment. The P use efficiency increased particularly when compost was part of the nutrient supply. The results suggest that replacing mineral fertilizer with compost accounting for 40 to 70% of the total N supply would be a suitable option for increasing the nutritional quality of maize grains and to efficiently use fertilizers on this Nitisol. ARTICLE HISTORY
... Degradation of soils in Ethiopia is also attributed to the reduced use of organic amendments due to competing uses of crop residues and animal manures for fuel (Amede et al., 2001;Nyssen et al., 2015;Wassie, 2020). This is exacerbated by climate change and extreme weather events, such as the recent El Niño effect, which significantly increased the risk of soil erosion, and soil carbon and nutrient losses (Smith et al., 2019). ...
... Reducing burning of crop residues in the fields could be of benefit, both to the atmosphere and to soils and crop production. Pyrolysis of the crop residues that would otherwise be burnt and incorporation of the biochar produced into the soil has been proposed as a potential approach to increase soil organic matter, while avoiding problems with N deficiency due to incorporating low N crop residues (Han et al., 2018) and the associated need for extra fertilisers, water, time or space in the rotation (Mohan et al., 2018;Smith et al., 2019;Bhattacharyya et al., 2020). ...
... However, composting is labour intensive (Smith et al., 2015;Chander et al., 2018) and requires addition of nutrient rich materials to co-compost with the straw (Roca-Pérez et al., 2009), while anaerobic decomposition requires ready access to water and equipment for the digestion process (Smith et al., 2015;Bansal et al., 2017). Therefore, in labour or water limited farming systems, composting and anaerobic digestion may not be feasible either (Smith et al., 2019). In-situ priming with innoculants has potential to circumvent N immobilisation using fungi that are adapated to use organic matter with a higher C to N ratio than bacteria to facilitate initial decomposition and release of the N contained in the straw itself (Gaind and Nain, 2007;Kumar et al., 2019). ...
... captured on the biochar before application, so are not included as potential sources of N for biochar enrichment. By contrast, the large losses of N from livestock systems, which occur during housing, manure storage and spreading (Reidy et al., 2009), have high potential to be captured on biochar, so are the focus of the estimates of N available for soprtion on the farm (Jassal et al., 2015;Smith et al., 2019;Keskinen et al., 2021). Losses of N from animal systems depend on the urine to faeces composition of the manure, management of the manure and the environmental conditions (Bussink and Oenema, 1998). ...
The aim of this paper is to quantify the impact of incorporating biochar into soils on net nitrogen waste from farming systems in India. It assumes only crop residues that are currently burnt in the fields are used to produce biochar. It accounts for losses of nitrogen occuring during pyrolysis, and the potential savings due to capture of reactive nitrogen from other parts of the farming system and from industry and energy sectors. In 2020, this could have been used to capture up to 67% of the nitrogen lost as nitrogen oxides and ammonia from the energy, industry and farming sectors. This is equivalent to 31% of the nitrogen that was applied as fertilisers and so could be an important tool in efforts to meet the United Nations target to reduce nitrogen waste by 50% by 2030. However, if the rate of nitrogen capture is low, alternative uses for crop residues are developed, or wasted nitrogen is successfully captured by other methods, the benefits of nitrogen capture on biochar could be much lower. Nevertheless, using biochar as a method to deliver wasted nitrogen to crops is likely to sequester more carbon than alternatives because pyrolyzed carbon is highly recalcitrant. It is also likely to be a more reliable method of capturing nitrogen emissions and delivering nitrogen to crops because emissions of ammonia during storage and spreading of compost or bioslurry can be high. Therefore, even if alternative uses of crop residues are favoured by farmers, it is recommended that nitrogen sorption on biochar should be part of the process, whether it is by direct capture of nitrogen from urine and industrial nitrogen oxide emissions, or by mixing of biochar with compost or the ammonium rich bioslurry produced by anaerobic digestion.
... Evidence from a range of authors suggests that 30-60% of crop residue dry matter can be removed from land without impacting sustainable crop production [144,145]. This is required to reduce erosion, but does not ensure maintenance of soil organic matter and nutrient content, which is becoming critical to continued crop production in many places in the world [146,147]. Other analyses suggest that if 20% of the soil surface is covered by crop residues, soil erosion will be reduced by 50% [148], and if 90% is covered, this increases to a reduction in water erosion of 93% compared with the uncovered soil [149]. ...
... In addition to this, the organic matter that is incorporated may be more recalcitrant than in untreated manure. Smith et al. [146] used simulation modelling to consider the impact of different treatments on C sequestration in soils and crop production, and surmised that anaerobic digestion of manures before incorporation actually increases C sequestration compared with untreated manures owing to the stabilization of organic matter by the digestion process [98,111]. ...
Soils have both direct and indirect impacts on available energy, but energy provision, in itself, has direct and indirect impacts on soils. Burning peats provides only approximately 0.02% of global energy supply yet emits approximately 0.7–0.8% of carbon losses from land-use change and forestry (LUCF). Bioenergy crops provide approximately 0.3% of energy supply and occupy approximately 0.2–0.6% of harvested area. Increased bioenergy demand is likely to encourage switching from forests and pastures to rotational energy cropping, resulting in soil carbon loss. However, with protective policies, incorporation of residues from energy provision could sequester approximately 0.4% of LUCF carbon losses. All organic wastes available in 2018 could provide approximately 10% of global energy supply, but at a cost to soils of approximately 5% of LUCF carbon losses; not using manures avoids soil degradation but reduces energy provision to approximately 9%. Wind farms, hydroelectric solar and geothermal schemes provide approximately 3.66% of energy supply and occupy less than approximately 0.3% of harvested area, but if sited on peatlands could result in carbon losses that exceed reductions in fossil fuel emissions. To ensure renewable energy provision does not damage our soils, comprehensive policies and management guidelines are needed that (i) avoid peats, (ii) avoid converting permanent land uses (such as perennial grassland or forestry) to energy cropping, and (iii) return residues remaining from energy conversion processes to the soil.
This article is part of the theme issue ‘The role of soils in delivering Nature's Contributions to People’.
The agricultural practice is a foundation for all global development. Increasing its production and productivity may affect the land capacity in the future if not managed sustainably. Sustainable agriculture could be one way to preserve land use potential. However, several obstacles impede its implementation, such as high reliance on external inputs to boost short-term output, lack of innovative technology in developing countries, and climate change impacts. Despite these obstacles, a variety of tackling options have been proposed, like decreasing the excessive usage of artificial fertilizer and relying on locally available organic materials as sources of plant nutrients. Improving small-scale irrigation practices by managing their negative environmental effects in small-scale agriculture could also enhance sustainable agriculture. This chapter briefly overviews sustainable agriculture, its components, and the potential and obstacles to achieving overall sustainability in both developed and developing countries.
This chapter casts light on the main conclusions and recommendations of the 13 chapters presented in the book titled “Environment Management: Waste to Wealth in India”. In addition, some findings from a few recently published research work related to environmental management. Therefore, this chapter contains information on waste to wealth in India, waste to energy and waste and sustainability. In addition, a set of recommendations for future research work is pointed out to direct future research towards environmental management, which is the main subject of strategic importance under Indian circumstances.KeywordsEnvironmentManagementWasteIndiaWealthEnergySustainability
Biogas digester programmes have been rolled out across many countries in sub-Saharan Africa over the past decade with varying levels of success. In Ethiopia, reported success rates have been low, despite high levels of interaction between non-governmental organisations and various levels of government, plus the establishment of practical eligibility criteria. In Halaba, Ethiopia, we investigated physical and social factors affecting feedstock and water availability using a face-to-face questionnaire-based survey (n = 112) in four kebeles (local administration areas). We found that practices of fuel use and water collection were markedly different between seasons. Fuel use was almost entirely dependent on season, with wood being burned in the wet season and crop residues and cow dung being used instead in the dry season. A matched pair t-test found a significant difference between seasons in terms of water collection times (p = 7.4 × 10⁻¹⁶), with households spending more time and money obtaining clean drinking water in the dry season. Results indicate that seasonal differences in resource availability may reduce the proportion of households that meet the physical characteristics for maintaining a biogas digester by approximately 62% from wet season to dry season. Conversely, the greatest benefits of digester use would be gained in the dry season, when dung could be returned to the soil as a nutrient-rich bioslurry, instead of being combusted as a dirty and inefficient fuel. Seasonality is rarely considered in feasibility studies, so we recommend that these factors should be built into future analyses.
Agriculture is the backbone of the Ethiopian economy, and the agricultural sector is dominated by smallholder farming systems. The farming systems are facing constraints such as small land size, lack of resources, and increasing degradation of soil quality that hamper sustainable crop production and food security. The effects of climate change (e.g., frequent occurrence of extreme weather events) exacerbate these problems. Applying appropriate technologies like climate-smart agriculture (CSA) can help to resolve the constraints of smallholder farming systems. This paper provides a comprehensive overview regarding opportunities and challenges of traditional and newly developed CSA practices in Ethiopia, such as integrated soil fertility management, water harvesting, and agroforestry. These practices are commonly related to drought resilience, stability of crop yields, carbon sequestration, greenhouse gas mitigation, and higher household income. However, the adoption of the practices by smallholder farmers is often limited, mainly due to shortage of cropland, land tenure issues, lack of adequate knowledge about CSA, slow return on investments, and insufficient policy and implementation schemes. It is suggested that additional measures be developed and made available to help CSA practices become more prevalent in smallholder farming systems. The measures should include the utilization of degraded and marginal lands, improvement of the soil organic matter management, provision of capacity-building opportunities and financial support, as well as the development of specific policies for smallholder farming.
