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Vermicompost Improves Physicochemical Properties of Growing Medium and Promotes Plant Growth: a Meta-analysis
Abstract
The use of vermicompost (VC) in growing medium can potentially promote plant growth and provide a way to reuse biowaste. Although VC has widely been studied recently in the production of growing medium, a quantitative assessment of the effects of VC on the physicochemical properties of the growing medium and plant growth is lacking. Therefore, we conducted a meta-analysis to synthetically evaluate the effects of VC on the physicochemical properties of growing medium and plant growth. We observed that VC significantly increased the nutrient content of the growing medium; in particular, it increased the contents of available nitrogen and phosphorus by 133.8% and 256.7%, respectively. Furthermore, VC significantly improved the water-holding porosity of the growing medium by 25.3% but slightly reduced total pore space by 2.6%. Moreover, during plant growth, VC increased seed germination rate, seedling index, shoot biomass, root biomass, and total biomass on an average by 30.4%, 57.8%, 52.6%, 58.3%, and 54.4%, respectively. Comprehensively, we also observed that cattle manure-VC was the most promising material for the production of growing medium and that the optimum proportion of VC for plant growth in growing medium was 40–60%. These results are therefore proposed to provide a reference for the regulation of the physicochemical properties of growing medium, including the selection of waste materials and the VC proportion during the production of growing medium. Similarly, the positive effects of VC on plant growth will provide more possibilities for reducing fertilizer input and cycling waste.
... Fernandez-Luqueno et al. (2010) reported that the presence of minerals like P and K stimulated kidney bean emergence 6 with the use of vermicompost. In a recent study, Ma et al. (2022) discovered that adding vermicompost to the growing medium resulted in a 30.4% increase in germination and a 57.8% increase in the seedling index. Truong and Wang (2015) found greater emergence and elongation of seedlings for both tomato cultivars in a mixture consisting of equal parts vermicompost, rice husk ash, and coconut fibre. ...
... The improvement of growth characteristics by vermicompost may be due to the nitrogen content of the media (Table 2) Sallaku et al. (2009) found that vermicompost application increased cucumber growth compared to commercial peat. According to Ma et al. (2022), the optimal rate of vermicompost to improve plant growth characteristics was 40-60%. In a different study focusing on 2 tomato varieties, Truong and Wang (2015) observed that mixing rice husk ash and coconut fibre with various ratios of vermicompost produced mixtures that enhanced seedling diameter, height, and the number of leaves. ...
... Rivera et al. (2022) reported that vermicompost and peat media provided similar results with respect to leaf area and biomass ratios in two different watermelon cultivars. Ma et al. (2022) found that vermicompost in the growing medium increased total biomass by 54.4%. Mupambwa et al. (2017a) discovered that the leaf area of tomato and cabbage seedlings was highest in mixtures of 25-50% chicken manure vermicompost and pine bark. ...
It is wondered whether vermicompost can be an alternative to peat in seedling production. Therefore, this study investigated the effects of different vermicompost rates on the growth, quality characteristics and macro and micro mineral concentrations of pepper and cauliflower seedlings. There were 4 treatments consisting of different mixtures in the study. T1: 70% peat + 27% perlite + 3% vermiculite; T2: 70% vermicompost + 27% perlite + 3% vermiculite; T3: 35% peat + 35% vermicompost + 27% perlite + 3% vermiculite; T4: 100% vermicompost. ‘Sivrillo’ F1 (Capsicum annuum var. longum) pepper and ‘Casper’ F1 (Brassica oleraceae var. botrytis) cauliflower varieties were used as the plant material. Vermicompost mixtures had a significant impact on pepper and cauliflower seedlings. The emergence and growth characteristics of pepper seedlings were similar in T1, T2 and T3 treatments. However, the T3 mixture provided the highest emergence rate and seedling height in cauliflower seedlings. T3 also increased the leaf area both pepper and cauliflower seedlings more than the other treatments. Although T2 medium showed the highest N, K, and Mg contents in pepper seedlings, vermicompost mixtures had the highest P, K, Ca, and Mg concentrations in cauliflower. Vermicompost mixtures had higher microelement contents in cauliflower, whereas similar results were obtained from T2 and T1 treatments in pepper seedlings. In conclusion, it was determined that the 35% peat and 35% vermicompost mixture was appropriate for pepper and cauliflower seedlings in terms of many criteria. Additionally, noteworthy results were obtained when 70% peat was substituted with vermicompost.
... Among the main components, animal excrement, particularly cow dung, is commonly used along with dried and chopped crop leftovers. To enhance the quality of vermicompost, a combination of leguminous and non-leguminous agricultural leftovers is often employed, as it provides a balanced mix of nutrients for the earthworms [2,22]. ...
Vermicompost is a nutrient-rich biological fertilizer with a variety of microorganisms that are thought to be significant in increasing the growth and yield of various field crops, vegetables, flowering plants, and fruit trees. Vermicomposting has attracted a lot of attention as an extensive approach for restoring the environment, producing nutrient-rich bio-fertilizers, and growing crops in a sustainable manner. It isploying earthworms to break down complex organic waste into simpler materials that could be taken up by plants. Vermicomposting yields a valuable byproduct called vermi-wash, which enhances crop resistance against diseases, stimulates seed germination, and improves overall plant vigor. This research paper sheds light on the significance of vermicomposting as a sustainable waste management solution and an eco-friendly means to enhance agricultural productivity. It emphasizes the importance of understanding the composition and quality of vermicompost, the materials used in the process, the vermicomposting procedure, and the subsequent effects on crop performance. Through the adoption of vermicomposting practices, agricultural systems can become more environmentally friendly, economically viable, and resilient for a sustainable future.
... Vermicompost, due to its organic nature, provides a rich source of plant nutrients that are readily available for uptake, including essential macro-and micro-elements that directly stimulate plant growth (Ma et al. 2022;Ramnarain, Ori, and Ansari 2017). The presence of biologically active substances, such as humic and fulvic acids, in vermicompost, plays an indirect role in promoting plant growth by enhancing nutrient availability, root development, and soil microbial activity (Singh et al. 2018). ...
... Vermicompost is one of the nutritive organic fertilizers that is produced through the digestive system of earthworms (Bhat et al. 2018). This organic fertilizer provides growth-promoting biostimulants and nutrients to plants and increases the growth and tolerance of plants against various stresses (Amooaghaie and Golmmohamadi 2017;Amooaghaie and Mardani Korani 2018;Karmakar et al. 2021;Ma et al. 2022). The application of vermicompost improves the physico-chemical characteristics and biological activity of soil and modifies metal(loid)s bioavailability, thereby can affect phytoremediation efficiency (Bhat et al. 2018). ...
Arsenic (As) is a hazardous metalloid, and mycorrhizal inoculation and vermicompost amendment can influence As bioremediation. However, the studies concerning the sole and joint effects of arbuscular mycorrhizal fungi (AMF) and vermicompost on the phytoremediation efficacy are limited. In the present study at first, the impact of various levels of vermicompost (0, 2, 4, and 8% w/w) was investigated on As mobility in soil and safflower (Carthamus tinctorius L.) plants grown in soils of spiked with 0, 40, and 80 mg kg−1 As. Results revealed that with increasing dose of vermicompost, bioavailable As in soil decreased which resulted in a lower bioaccumulation factor and translocation factor (TF) and led to a significant increase of tolerance index (TI) and total chlorophyll content in plants. The highest effect on TI and total As accumulation per plant was obtained in the dosage of 8% vermicompost. Therefore, in the second experiment, the sole and joint effects of 8% vermicompost and inoculation with Rhizophagus intraradices were assessed on the tolerance and accumulation of As in safflower. The addition of vermicompost aggravated mycorrhizal colonization but did not significantly influence mycorrhizal dependency under As stress. The joint effects of AMF and vermicompost improved the dry weight of roots and shoots, increased P concentration and P:As ratio in shoots, reduced malondialdehyde content, and moderated ascorbate peroxidase activity in leaves of As-stressed plants. Interestingly, co-application of AMF and vermicompost more than their sole usage decreased As concentration in shoots and TF and more strongly increased total As accumulation per plant. These findings suggest that mycorrhizal inoculation and vermicompost have a synergistic effect on As tolerance and phytostabilization efficacy of safflower plants, and their combined application may be a new option to remediate As-contaminated soils.
Aim: Methodology: Results: Interpretation: To evaluate the physico-chemical and hydrological characteristics of cocopith, perlite, vermicullite, vermicompost, sand, rice husk, paddy straw, saw dust and rock wool for using them as substrates for soilless agriculture. The soilless substrates were initially evaluated for pH and EC, and then estimated for total organic carbon by dry combustion method, total nitrogen by Kjeldahl digestion method, potassium by atomic absorption and phosphorus by colorimetric method. The hydrological properties of substrates were estimated by Keen-Rackzowski box method. The desirable level of physical properties of-3 bulk density (0.47 gm cm), particle density (0.63 gm-3 cm), total porosity (75.81%) and chemical properties of-1 pH (6.23), EC (5.02 dS m), total organic carbon (36.39 %), and other properties were noticed under cocopith. The maximum level of water holding capacity (769.30 %) and volume of expansion (185.78 %) was registered by cocopith. Cocopith has favourable hydrological properties with desirable level of physical and chemical properties, which makes it the best medium for soilless agriculture. Coconut fiber is a characteristic natural fiber from the external husk of coconut and its extraction process also without polluting nature.
Food production and waste management are two increasing issues ensuing from the growing world population. Recycling organic residues into amendment for food production seems to appear as an opportunity to partially solve this double challenge. Vermicomposting is a process whereby earthworms transform organic residues into compost that can be used as a substrate for plant growth. Many studies have evaluated the effect of vermicompost on plant growth, but a quantitative summary of these studies is still missing. This is the first meta-analysis providing a quantitative summary of the effect size of vermicompost on plant growth. We found that vermicompost brought about average increases of 26% in commercial yield, 13% in total biomass, 78% in shoot biomass, and 57% in root biomass. The positive effect of vermicompost on plant growth reached a maximum when vermicompost represented 30 to 50% of the soil volume. The best original material to be used for vermicompost production was cattle manure. The effect was stronger when no fertilizer was added, and lower when the standard Metro-Mix 360 substratum recommended by some authors was used as a growing medium in greenhouse or climatic chambers. Herbs (especially Cucurbitaceae and Asteraceae) and legumes exhibited the largest biomass increase in the presence of vermicompost. These results are discussed through an analysis of potential publication biases showing an over-representation of studies with a high effect size. We finally recommend authors of primary research to provide a minimum set of statistical parameters, output variables, and experimental condition parameters to make it easier to include their work in meta-analyses. Overall, our study provides synthetic information on the beneficial effects of vermicompost for plant growth, which could help bring waste management and agriculture together towards a society with a more circular economy.
Decreasing arable land, rising urbanization, water scarcity, and climate change exert pressure on agricultural producers. Moving from soil to soilless culture systems can improve water use efficiency, especially in closed-loop systems with a recirculating water/nutrient solution that recaptures the drain water for reuse. However, the question of alternative materials to peat and rockwool, as horticultural substrates, has become increasingly important, due to the despoiling of ecologically important peat bog areas and a pervasive waste problem. In this paper, we provide a comprehensive critical review of current developments in soilless culture, growing media, and future options of using different materials other than peat and rockwool. Apart from growing media properties and their performance from the point of view of plant production, economic and environmental factors are also important. Climate change, CO2 emissions, and other ecological issues will determine and drive the development of soilless culture systems and the choice of growing media in the near future. Bioresources, e.g., treated and untreated waste, as well as renewable raw materials, have great potential to be used as growing media constituents and stand-alone substrates. A waste management strategy aimed at reducing, reusing, and recycling should be further and stronger applied in soilless culture systems. We concluded that the growing media of the future must be available, affordable, and sustainable and meet both quality and environmental requirements from growers and society, respectively.
Soilless culture systems (SCS) are increasingly adopted as a major technological component in the modern greenhouse industry. The core advantage of soilless culture, frequently referenced to as “hydroponics”, is the independence of the crop from the soil which, as a natural medium, is heterogeneous, accommodates pathogens, tends to degrade in monoculture systems, and may be infertile, saline or sodic. The cultivation on horticultural growing media (GM) such as rockwool, perlite, and coconut is worldwide the most frequently used SCS for production of fruit vegetables and cut flowers. Water culture systems such as floating hydroponics, Nutrient Film Technique and aeroponics are mainly used for production of leafy vegetables. Modern, fully automated fertigation heads are used for the preparation and timely supply of nutrient solution (NS), which serves both the nutrition and irrigation of the plants. In soilless culture, the NS that drains out of the root zone can be easily collected and recycled, thereby considerably increasing the water use efficiency and minimizing environmental impacts arising from fertilizer residues. The spread of pathogens via the recycled effluents is a challenge that can be encountered by introducing a suitable system for their disinfection before reusing, based mainly on UV radiation, slow sand or membrane filtration, or a chemical treatment (mainly O3, H2O2 or chlorination). In SCS, the NS composition has to be adapted to the composition of the water used for its preparation, the plant species and even the cultivar, the growth stage, the season of the year and the current climatic conditions, and this is a challenge that can be encountered by using modern information and computer technologies. Last but not least, the frequency of irrigation in GM-grown crops is high due to the limited volume of rooting medium per plant and has to be efficiently controlled. Suitable automation technologies are mostly based on real-time measurement of parameters related either to the greenhouse microclimate (e.g., solar radiation, vapor pressure deficit, air temperature) or to the GM water status (water tension or content).
Background
Organic soilless production in containers requires substrates with appropriate physicochemical and biological properties to ensure that production is sustainable and profitable for several production cycles. The main objective of this study was to comprehensively evaluate these properties in three different mixtures of organic substrates (vermicompost [V] and coconut fibers [CF] in ratios 20V80CF, 40V60CF, 60V40CF) for four horticultural crop production cycles (PCs) using vermicompost tea (VT) as the main source of nutrients.
Results
Readily available water (25%) in the control treatment (20V80CF) was below the recommended limit, and dry bulk density (>450 g/L) surpassed the recommended limit in the 60V40CF treatment (p < 0.05). In terms of chemical properties, cations and anions in the saturated media extract decreased significantly to values below established optimal conditions. Furthermore, the substrates presented high enzymatic activity in successive production cycles (p < 0.05), including dehydrogenase (350–400 μg TFF g⁻¹), acid phosphatase (4,700 μg p‐nitrophenol g⁻¹ soil hr⁻¹), and β‐glucosidase (1,200 μg p‐nitrophenol g⁻¹ soil hr⁻¹) activity during transformation from organic matter to inorganic compounds.
Conclusion
The 40V60CF treatment presents adequate physicochemical and biological characteristics for reuse for more than four growing cycles when organic supplements are administered.
The accumulation of organic matter in the form of plant remains at the various stages of decomposition results in the formation of peat. A very low land, water logged and excessive rainfall regions are the highest places of its occurrence. The presence of organic matter plays a major role in governing physicochemical and engineering properties of peat. The wide spatial variations in inherent properties of peat contribute high water content, low shear strength, high compressibility and high void ratio. The exploration of peatland has been done by the various researchers in many places across the world; however, in India, proper knowledge on peatland periphery is still obscure. This article highlights brief information on physicochemical properties of Northeast-Indian peat. Further, an extensive literature review is also carried out on physicochemical and engineering, microstructural and thermal characteristics of peat in worldwide and their various classification systems. The correlations developed based on present study and literature data on physical properties of peat are also presented.
Peat based growing media are not ecologically sustainable and often fail to support biological control. Miscanthus straw was (1) tested to partially replace peat; and (2) pre-colonized with a Trichoderma strain to increase the biological control capacity of the growing media. In two strawberry pot trials (denoted as experiment I & II), extruded and non-extruded miscanthus straw, with or without pre-colonization with T. harzianum T22, was used to partially (20% v/v) replace peat. We tested the performance of each mixture by monitoring strawberry plant development, nutrient content in the leaves and growing media, sensitivity of the fruit to the fungal pathogen Botrytis cinerea, rhizosphere community and strawberry defense responses. N immobilization by miscanthus straw reduced strawberry growth and yield in experiment II but not in I. The pre-colonization of the straw with Trichoderma increased the post-harvest disease suppressiveness against B. cinerea and changed the rhizosphere fungal microbiome in both experiments. In addition, defense-related genes were induced in experiment II. The use of miscanthus straw in growing media will reduce the demand for peat and close resource loops. Successful pre-colonization of this straw with biological control fungi will optimize crop cultivation, requiring fewer pesticide applications, which will benefit the environment and human health.
Soilless cultivation is recognized globally for its ability to support efficient and intensive plant production. While production systems vary, most utilize a porous substrate or growing medium for plant provision of water and nutrients. Until relatively recently, the main drivers for the selection of the component materials in growing media were largely based on performance and economic considerations. However, increasing concern over the environmental impacts of some commonly used materials, has led researchers to identify and assess more environmentally sound alternatives. There has been an understandable focus on renewable materials from agricultural, industrial and municipal waste streams; while many of these show promise at an experimental level, few have been taken up on a significant scale. To ensure continued growth and sustainable development of soilless cultivation, it is vital that effective and environmentally sustainable materials for growing media are identified. Here we describe the factors influencing material selection, and review the most commonly used organic materials in relation to these. We summarise some of the renewable, primary and waste stream materials that have been investigated to date, highlighting the benefits and challenges associated with their uptake. In response to the need for researchers to better identify promising new materials, we present an evidence-based argument for a more consistent approach to characterising growing media and for a clearer understanding of the practical and economic realities of modern soilless cultivation systems.
Growth media used for growing containerized plants in greenhouses have changed greatly since the initiation of the Spurway test procedure (8). Well-aggregated field soils gradually gave way to mixtures of soil and manufactured coarse amendments and eventually to soilless growth media. Along with these changes in growth media composition came changes in physical and chemical properties—some desirable, some not so desirable. Field soils generally have a high-nutrient capacity value and a low-intensity factor. The level of the capacity factor has decreased as the change in growth media composition has taken place. Geraldson (1-3) developed an “intensity and balance” analysis system for the unique, sandy soils of Florida; soils that provide little buffering capacity. He found the concentration (intensity) and balance of nutrients in the soil solution to be important when the capacity factor was small. Similarly, the concentration and balance of nutrients in the solution phase of greenhouse growth media today have become important to plant growth and quality.
In the last decades the fraction of fresh produce and cut flowers that are grown in soilless media are constantly growing due to the inherent advantages of substrates over soils. Peat moss is being used for many years as a main component of soilless media, mainly due to its excellent physical properties. Recently peat is frequently replaced by a variety of recycled, aerobically-stabilized materials, also known as composts. This trend is driven by the societal need to recycle organic wastes in an environmentally-sensitive manner, by the rising cost of peat and by peat conduciveness to several soil-borne diseases. Proper composting of many types of organic wastes achieves a number of important objectives. It should eliminate phytotoxicity, pathogens and weed seeds, and stabilize the material with respect to N and oxygen demand of microorganisms. In addition, some composts are suppressive against several soil-borne diseases. Compost maturity is a crucial characteristic in relation to its use in growing media. It ensures minimal medium shrinkage, oxygen consumption, nitrogen immobilization and phytotoxicity. Feedstocks for composts include bark, sawdust, spent mushroom compost, grape marc, composted green wastes, rice hulls, animal manures, biowaste and others. Limitations to the use of composts in growing media are their physical properties (high bulk density, low content of easily available water), salinity, high pH and rate of residual degradation with time. As a result, normally the fraction of the compost in the mixture should not exceed 50%, although some exceptions exist. Advantages of composts as ingredients of growing media include their low cost, nutritional contribution and suppressiveness against soil-borne diseases. A clear advantage of composts used in substrates is that most of them can be further recycled, after the end of the growing cycle, by soil application. Required future research includes the effect of composting techniques and feedstocks on compost characteristics and predicted performance. The effect of compost storage on the shelf life of its desirable properties should also be studied.
Four experiments were conducted under greenhouse conditions in Oklahoma. Pelleted 'Genovese' basil (Ocimum basilicum) seeds were sown in polystyrene flats with six different blends of a peat-lite mix (PLO) and yard waste compost [YWC (this batch designated CO)] in 2012 for the first two experiments. The proportions by volume of PLO:CO included 100%:0%, 80%:20%, 60%:40%, 40%:60%, 20%:80%, and 0%:100%. Seedling establishment was unaffected consistently, but there was a distinct decline in seedling height and dry weight between 100% PLO and 80% PLO:20% CO, followed by smaller decreases as the percentage of compost increased in the blends. A third experiment was conducted in 2013 with a different batch of peat-lite (PL1) after the compost had aged 17 months (now designated Cl). Treatments were 100% PL1, 80% PL1:20% Cl, and 80% PL1:20% Cl mixed with sulfur (S) at 1, 2, or 3 lb/yard(3) of blend to acidify the media. The 100% PL1 treatment delayed seedling emergence and suppressed height and dry weight relative to seedlings grown in 80% PL1:20% Cl blends. The PL1 subsequently was found to have been produced in 2010, and the wetting agent had apparently degraded. The aged 2012 compost (Cl) was not inhibitory to basil seedling growth when blended at 20% with the PL1, and in fact restored utility to the PL1. The carbon:nitrogen ratio of the original 2012 compost (CO) was 10.8:1, suggesting stability. It appeared that the main reason the CO compost was inhibitory was that mineralization was slow or immobilization occurred, causing a lack of plant-available nitrogen, especially nitrate. Treatments with S lowered pH of the media, but there were no differences in basil seedling growth between the unamended 80% PL1:20% Cl blend and blends with added S. A fourth experiment compared three peat-lite media: PL1; a batch of the same medium as PL1 that was produced in 2013 (PL2); and a different medium also produced in 2013 (PL3). Peat-lite media were either used unblended, or blended with 20% Cl or 20% C2 (a fresh batch of YWC obtained from the same facility that had produced the original CO). The unamended PL1 was again inhibitory to basil seedling establishment and development. The two "fresh" peat-lite media (PL2 and PL3) were not inhibitory and were similar to each other in performance. A blend of 80% PL2 or 80% PL3 with 20% compost produced similar (C2) or somewhat better (Cl) results than were obtained with the unarnended peat. We conclude that a blend of 80% peat-lite medium and 20% YWC can be used to produce basil transplants. However, producers must consider the quality of the peat-lite medium and the compost based on the age and composition of the components.
Vermicomposts, produced commercially from cattle manure, market food waste and recycled paper waste, were applied to small replicated field plots planted with tomatoes (Lycopersicon esculentum) and bell peppers (Capsicum anuum grossum) at rates of 10 t ha−1 or 20 t ha−1 in 1999 and at rates of 5 t ha−1 or 10 t ha−1 in 2000. Food waste and recycled paper vermicomposts were applied at the rates of 5 t ha−1 or 10 t ha−1 in 2000 to replicated plots planted with strawberries (Fragaria spp.). Inorganic control plots were treated with recommended rates of fertilizers only and all of the vermicompost-treated plots were supplemented with amounts of inorganic fertilizers to equalize the initial N levels available to plants in all plots at transplanting. The marketable tomato yields in all vermicompost-treated plots were consistently greater than yields from the inorganic fertilizer-treated plots. There were significant increases in shoot weights, leaf areas and total and marketable fruit yields of pepper plants from plots treated with vermicomposts compared to those from plots treated with inorganic fertilizer only. Leaf areas, numbers of strawberry suckers, numbers of flowers, shoot weights, and total marketable strawberry yields increased significantly in plots treated with vermicompost compared to those that received inorganic fertilizers only. The improvements in plant growth and increases in fruit yields could be due partially to large increases in soil microbial biomass after vermicompost applications, leading to production of hormones or humates in the vermicomposts acting as plant-growth regulators independent of nutrient supply.
We evaluated the feasibility of incorporating vermicompost as a potting amendment into a commercial ornamental production system. Pansies (Viola × wittrockiana subsp. Delta) and primulas (Primula acaulis subsp. Oriental) were grown in peat-based conventional greenhouse medium substituted with 5%, 15% and 25% (v/v) commercial and pig slurry vermicompost. Vegetative growth and flowering were evaluated and compared to plants grown with 0% vermicompost. We observed a general reduction of growth in both species with increasing concentrations of commercial and pig slurry vermicompost. The highest percentage of vermicompost (25%) showed 20% of plant mortality, high levels of stress and damage to the photosynthetic apparatus, as well as a significant reduction in the number and biomass of leaves and in flower production. Most likely, the increase in electrical conductivity and pH interacted synergistically with the decrease in air space produced after the application of vermicompost and were magnified under sub-irrigation, causing the observed effects on plant growth. Therefore the cultivation system must be taken into account when incorporating vermicompost as a growing media constituent in commercial conditions.
The financial effectiveness of the soilless culture system (SCS) of gerbera (Gerbera jamesonii Bol. ex Adlam.) production was compared with that of the soil culture system in heated greenhouses in northern Greece. Evaluation was based on budgeting procedures that assumed a project life of 9 years. The decision to accept or to reject the investment was based on the following criteria: 1) net present value analysis (U.S. $18,414), 2) benefit/cost ratio, and 3) risk exposure ratio. The soilless culture system, particularly the plastic bag system using perlite media, was more profitable. Application of sensitivity analysis illustrated the significance of product price and discount rate in determining the accrued benefits.
Greenhouse experiments were conducted to evaluate the effects of different concentrations of vermicompost water extracts (teas) and seed soaking duration on germination of tomato (Solanum lycopersicum) and lettuce (Lactuca sativa) seeds. In the first experiment, tomato and lettuce seeds were soaked in vermicompost teas prepared from chicken manure-based vermicomposts for 9 hours. The concentrations of the extractsusedwere10%, 5%, 3%, 1%(1:10, 1:20, 1:33, and1:100vermicompost-to-water ratio by volume), and 0% (water control). Seeds were sown in peat-perlite medium, and seedlings were harvested after 4 weeks. Soaking seeds in vermicompost teas significantly (P<0. 0001)increased germination percentage and seedling growth of tomato and lettuce compared with control. The response to concentrations of the vermicom post tea was generally linear. In another experiment, tea produced from food waste-based vermicompost was used. Tomato seeds were soaked in 20%, 10%, 5%, 1%, and 0% teas after 24 hours of soaking and sown into a sphagnum moss-based medium. Plant responses were linear and quadratic for germination and growth, respectively, with 1% vermicom post tea increasing germination, whereas 5% vermicom post tea significantly promoted growth. A third experiment was done to evaluate the interaction of a range of vermicom post tea concentrations (20%, 10%, 5%, 1%, and 0%) and length of soaking (24, 12, 8, 4, 1 hours, and 0: no soaking) on the germination of tomato seeds. There was a significant interaction (P < 0. 001) between the concentration of vermicom post teas and lengths of soaking. Soaking duration generally had a significantly positive and linear effect on germination of tomato seeds across the concentrations of vermicom post tea. Germination rates of tomato seeds were significantly greater after 8, 12, and 24 hours of soaking. However, within each soaking duration, concentrations of vermicom post teas had variable effects on seed germination. The presence of N-indole-3-acetic acid (IAA), cytokinin, gibberellins, and humic acids in the teas could have been responsible for the faster germination of tomato seeds when soaked at lower concentrations and longer soaking times.
Despite a significant growth in food production over the past half-century, one of the most important challenges facing society today is how to feed an expected population of some nine billion by the middle of the 20th century. To meet the expected demand for food without significant increases in prices, it has been estimated that we need to produce 70-100 per cent more food, in light of the growing impacts of climate change, concerns over energy security, regional dietary shifts and the Millennium Development target of halving world poverty and hunger by 2015. The goal for the agricultural sector is no longer simply to maximize productivity, but to optimize across a far more complex landscape of production, rural development, environmental, social justice and food consumption outcomes. However, there remain significant challenges to developing national and international policies that support the wide emergence of more sustainable forms of land use and efficient agricultural production. The lack of information flow between scientists, practitioners and policy makers is known to exacerbate the difficulties, despite increased emphasis upon evidence-based policy. In this paper, we seek to improve dialogue and understanding between agricultural research and policy by identifying the 100 most important questions for global agriculture. These have been compiled using a horizon-scanning approach with leading experts and representatives of major agricultural organizations worldwide. The aim is to use sound scientific evidence to inform decision making and guide policy makers in the future direction of agricultural research priorities and policy support. If addressed, we anticipate that these questions will have a significant impact on global agricultural practices worldwide, while improving the synergy between agricultural policy, practice and research. This research forms part of the UK Government's Foresight Global Food and Farming Futures project.
The interactions between earthworms and microorganisms can produce significant quantities of plant growth hormones and humic acids which act as plant regulators. Experiments were designed to evaluate the effects of humic acids extracted from vermicompost and compare them with the action of commercial humic acid in combination with a commercial plant growth hormone, indole acetic acid (IAA) which is a commonly found in vermicomposts. In the first experiments, humic acids were extracted from cattle, food and paper waste vermicomposts. They were applied to a plant growth medium, Metro-Mix360 (MM360), at rates of 0, 250 or 500 mg humates kg −1 dry wt. of MM360, to marigold, pepper, and strawberry plants in the greenhouse. Substitution of humates ranging from 250 to 1000 mg kg −1 MM360 increased the growth of marigold and pepper roots, and increased the growth of roots and numbers of fruits of strawberries significantly. In other experiments, humic acids extracted from food waste vermicomposts were applied at a rate of 500 mg kg −1 dry wt. of MM360, singly or in combination with IAA at a rate of 10 −5 μM, to pepper seedlings. This experiment was designed to compare the differences in effects between the most effective dosage rate of humic acid from food waste, a phytohormone (IAA), and a commercial source of humic acid. The numbers of pepper flowers and fruits increased significantly in response to treatment with humic acid, IAA and a combination of humic acid and IAA. Peppers treated with humic acids extracted from food waste vermicomposts produced significantly more fruits and flowers than those treated with commercially-produced humic acids.
BACKGROUND: Multiple studies have been reported on the effect of compost tea on suppression of certain plant diseases. However, relatively little work has been done to investigate the effect of vermicompost tea on yield and nutritional quality of vegetable crops. In this study, experiments were conducted to determine the effect of extraction method on vermicompost tea quality and subsequent effects on growth, mineral nutrients, phytonutrients and antioxidant activity of pak choi plants grown under organic (vermicompost) and synthetic (Osmocote) fertilisation. Three vermicompost teas obtained by different extraction methods, namely non-aerated vermicompost tea (NCT), aerated vermicompost tea (ACT) and aerated vermicompost tea augmented with microbial enhancer (ACTME), were applied to the plants. Aerated water served as control.
RESULTS: Mineral nutrients were significantly higher in ACTME compared with other teas, but total microbial population and activity did not differ with extraction method. All vermicompost teas similarly enhanced plant production, mineral nutrients and total carotenoids, and this effect was most prominent under organic fertilisation. Antioxidant activity and total phenolics were higher under organic compared with synthetic fertilisation. Vermicompost teas generally decreased phenolics under organic fertilisation and increased them under synthetic fertilisation compared with the control.
CONCLUSION: The effect of vermicompost tea on crop growth is largely attributable to mineral nutrient, particularly N, uptake by plants. Non-significant differences among extraction methods on plant response within fertiliser regimes suggest that aeration and additives are not necessary for growth promotion and nutrient quality under the conditions reported here. Copyright
This review focuses mainly on eudicot seeds, and on the interactions between abscisic acid (ABA), gibberellins (GA), ethylene, brassinosteroids (BR), auxin and cytokinins in regulating the interconnected molecular processes that control dormancy release and germination. Signal transduction pathways, mediated by environmental and hormonal signals, regulate gene expression in seeds. Seed dormancy release and germination of species with coat dormancy is determined by the balance of forces between the growth potential of the embryo and the constraint exerted by the covering layers, e.g. testa and endosperm. Recent progress in the field of seed biology has been greatly aided by molecular approaches utilizing mutant and transgenic seeds of Arabidopsis thaliana and the Solanaceae model systems, tomato and tobacco, which are altered in hormone biology. ABA is a positive regulator of dormancy induction and most likely also maintenance, while it is a negative regulator of germination. GA releases dormancy, promotes germination and counteracts ABA effects. Ethylene and BR promote seed germination and also counteract ABA effects. We present an integrated view of the molecular genetics, physiology and biochemistry used to unravel how hormones control seed dormancy release and germination.
Problem statement: Cocopeat is considered as a good growing media component with acceptable pH, electrical conductivity and other chemical attributes but it has been recognized to have high water holding capacity which causes poor air-water relationship, leading to low aeration within the medium, thus affecting the oxygen diffusion to the roots. Incorporation of coarser materials into cocopeat could improve the aeration status of the media. Approach: Selected chemical and physical characteristics of five types of growing media comprising of (v/v) 100% cocopeat, 70% cocopeat: 30% burnt rice hull, 70% cocopeat: 30% perlite, 70% cocopeat: 30% kenaf core fiber and 40% cocopeat: 60% kenaf core fiber were determined and their suitability as growing media was tested using Celosia cristata. Data on pH, Electrical Conductivity (EC) and various aspects of air-water relationships of the media, as well on growth and flowering of test plant and leaf nutrient contents were collected. Results: Initial pH for 100% cocopeat and 70% cocopeat: 30% kenaf core fiber was higher than the other media but the values were eventually similar by the end of the study. The bulk density and EC of media containing burnt rice hull was markedly higher than the other media (0.12 g cm3 and 0.48 mS cm1, respectively). Media comprising of 70% cocopeat: 30% burnt rice hull and 70% cocopeat: 30% perlite contained higher air content. The former held the highest volume of available water. Incorporation of burnt rice hull and perlite into cocopeat increased water absorption ability of the media which reached saturation earlier than the other media. Addition of burnt rice hull (30%), perlite (30%) and kenaf core fiber (30%) to cocopeat elevated the Air-Filled Porosity (AFP) of the media. The growth and flowering of Celosia cristata were the greatest when grown in a mixture of 70% cocopeat: 30% burnt rice hull and perhaps linked with a good balance in the aeration and moisture relationship of the media. Conclusion: Results of this study indicated that certain chemical and physical properties of cocopeat can be improved through incorporation of burnt rice hull and its positive effect was clearly reflected in the growth and development of Celosia cristata.
The rise in international trade of plants and plant products has increased the risk of introduction and spread of plant pathogens and pests. In addition, new risks are arising from the implementation of more environmentally friendly methods of biodegradable waste disposal, such as composting and anaerobic digestion. As these disposal methods do not involve sterilisation, there is good evidence that certain plant pathogens and pests can survive these processes. The temperature/time profile of the disposal process is the most significant and easily defined factor in controlling plant pathogens and pests. In this review, the current evidence for temperature/time effects on plant pathogens and pests is summarised. The advantages and disadvantages of direct and indirect process validation for the verification of composting processes, to determine their efficacy in destroying plant pathogens and pests in biowaste, are discussed. The availability of detection technology and its appropriateness for assessing the survival of quarantine organisms is also reviewed.
This experiment was designed to characterize the physical, chemical and microbial properties of a standard commercial horticultural, greenhouse container, bedding plant medium (Metro-Mix 360), that had been substituted with a range of increasing concentrations (0%, 5%, 10%, 25%, 50% and 100% by volume) of pig manure vermicompost and to relate these properties to plant growth responses. The growth trials used tomatoes (Lycopersicon esculentum Mill.), grown in the substituted media for 31 days under glasshouse conditions, with seedling growth recorded in 20 pots for each treatment. Half of the tomato seedlings (10 pots per treatment) were watered daily with liquid inorganic fertilizer while the other half received water only. The percentage total porosity, percentage air space, pH and ammonium concentrations of the container medium all decreased significantly, after substitution of Metro-Mix 360 with equivalent amounts of pig manure vermicompost; whereas bulk density, container capacity, electrical conductivity, overall microbial activity and nitrate concentrations, all increased with increasing substitutions of vermicompost. The growth of tomato seedlings in the potting mixtures containing 100% pig manure vermicompost was reduced, possibly as a result of high soluble salt concentrations in the vermicompost and poorer porosity and aeration. The growth of tomato seedlings was greatest after substitution of Metro-Mix 360 with between 25% and 50% pig manure vermicompost, with more growth occurring in combinations of pig manure vermicompost treated regularly with a liquid fertilizer solution than in those with no fertilizer applied. Some of the growth enhancement in these mixtures seemed to be related to the combined effects of improved porosity, aeration and water retention in the medium and the high nitrate content of the substrate, which produced an increased uptake of nitrogen by the plant tissues, resulting in increased plant growth. When the tomato seedlings were watered daily with liquid inorganic fertilizer, substitution of Metro-Mix 360 with a very small amount (5%) of pig manure vermicompost resulted in a significant increase in the growth of tomato seedlings. Such effects could not be attributed solely to the nutritional or physical properties of the pig manure vermicompost. Therefore, it seems likely that the pig manure vermicompost provided other biological inputs, such as plant growth regulators into the container medium, that still need to be identified fully.
The appropriate mixture of growing media can greatly influence the growth, performances and yield of the crops. It is crucially important for the growing media to be amended in order to provide the suitable physical and chemical properties especially for the containerized plants. Thus, the objective of this study was to determine the suitable combination growing media mixture based on the physical and chemical properties of compost, topsoil and sand. These growing media were mixed in different proportions; Mix 1 containing compost: topsoil: sand in a ratio (1:2:3); (Mix 2) containing compost: topsoil: sand (2:2:1) and Mix 3 containing compost: topsoil: sand (3:2:1). The considered growing media physical and chemical properties included mechanical analysis %, bulk density (g/cm⁻³), pH, EC (dSm⁻¹), organic carbon (%), Total N (%), C:N and Cation Exchange Capacity (CEC). According to the results, mixture 3 with the combination of compost: topsoil: sand (3:2:1) gave the lowest bulk density compared with the other treatments. Furthermore, the pH and EC value of the mixture was at the suitable range for environmental value. In addition, the chemical properties of the growing media mixture 3 also achieved the highest CEC value, organic carbon and Total N. Based on the findings, it is concluded that potting mixture 3 that contained compost: topsoil: sand in a ratio (3:2:1) are recommended for the containerized plants.
The intensive use of inorganic fertilizers and pesticides in the agricultural field has globally destroyed soil fertility, killed beneficial microorganisms, and also decreased natural resistance in crops, thereby making them more vulnerable to diseases besides affecting human health and the environment. To overcome these problems, it is very important to shift our attention towards eco-friendly alternatives like vermicompost and vermicompost tea which not only can increase crop growth and yield, suppress diseases and pests sustainably but can also protect human health and the environment. Vermicompost with its rich nutrient content, plant growth promoters like auxins, gibberellins, cytokinins, and beneficial microbes not only improves the growth and yield of crops but also increases the diversity and activity of antagonistic microbes and nematodes, which helps to suppress pests and diseases caused by soil-borne phytopathogens. Vermicompost tea also has a tremendous potential to protect plants from diseases and its application to plants can coat leaf surfaces and reduce available sites for pathogen infection or increases microbial diversity that can kill harmful pathogens. Here, we review recent scientific achievements towards the management of crop diseases and pests by these organic amendments and the major points are the following: (1) production of vermicompost and vermicompost tea, (2) management of crop pests and diseases by vermicompost and vermicompost tea, and (3) the possible mechanisms and some important factors involved in the suppression of diseases and pests. Finally, we conclude that by using these eco-friendly organic amendments as a replacement to inorganic pesticides and fungicides, diseases and pests can be managed successfully without affecting human health and the environment and chemical-free food can be provided to humankind in the future.
Data analysis plays an increasing role in research, scientific expertise and prospective studies. Multiple data sources are often available to estimate a key parameter or to test a hypothesis of scientific or societal interest. These data, obtained under different environmental conditions or based on different experimental protocols, are generally heterogeneous. Sometimes they are not even directly accessible and should be extracted from scientific articles or reports. However, a comprehensive analysis of the available data is essential to increase the accuracy of estimates, assess the validity of research conclusions and understand the origin of the variability of the experimental results. A quantitative synthesis of the data set available allows for a better understanding of the effects of explanatory factors and for evidence-based recommendations.
Designed as a methodological guide, this book shows the interests and limitations of different statistical methods to analyze data from experimental networks and to perform meta-analyses. It is intended for engineers, students and researchers involved in data analysis in agronomy and environmental science. Our objective is to present the main statistical methods to analyze data from experimental networks and scientific publications. Each chapter exposes one or more methods and illustrates them with examples processed with the R software. Data and R codes are provided and commented in order to facilitate their adaptation to other situations. The codes can be reused from the KenSyn R package associated with this book.
Peatlands represent a valuable global carbon store and are critical for preserving biodiversity. In order to reduce peat mining a significant effort is made to search for substitutes of peat in its different uses. Organic products obtained by hydrothermal carbonization processes could fully or partially replace peat in growing media if they possess some suitable properties. The study focused on the properties of a hydrochar produced from wheat (HTC) and included its chemical characterization and stability estimates using microbial respiration and nitrogen mineralization essays. As inhibition to seed germination could significantly restrict the eventual use of HTC in growing media, a number of seed germination trials were carried out to reveal the magnitude of phytotoxicity in relation to sphagnum peat and biochar and the effect that some simple and low-cost pre-conditioning treatments have on the rate of germination. This rate was greatly increased by simply wetting the material a few days prior to use or by mixing it with compost. It was shown that the positive effect on seedling emergence should be attributed, at least partly, to the degradation by microorganisms of toxic substances presumably produced during carbonization.
This research evaluated green waste compost (GWC) and green waste vermicompost (GWV) as peat substitutes in growing media used for the production of geranium (Pelargonium zonale L.) and calendula (Calendula officinalis L.). Five growing media were prepared: 100% Peat (P), 50% Peat + 50% GWC (PC), 100% GWC (C), 50% Peat + 50% GWV (PV), and 100% GWV (V). Geranium and calendula seedlings were transplanted into each medium and were grown under commercial nursery conditions for 6 months, i.e., until they attained commercial size. The higher percentage of GWC and GWV in the growing medium could increase bulk density and air space; decrease total pore space and water-filled porosity; and increase pH, electrical conductivity, and macro-and microelement contents. The heavy metal contents of all growing media were within safe ranges. Particle-size distribution and fertility were superior in the vermicompost-based media than in the compost-based media. Geranium growth was reduced in media containing GWC (C and PC). Calendula growth in compost-based growing media was similar to or greater than growth in pure peat. Geranium and calendula growth and flowering were superior in all vermicompost-based media (PV and V) than in the control medium (P). These results indicate that GWV is better than GVC as a partial substitute for peat in the cultivation of geranium and calendula.
With the increasing availability of composted and other organic alternatives to peat in the UK and continuing encouragement to use them, growing media manufacturers have begun to seek assurance that every substrate they use, including peat, is free of plant and human pathogens. This study was initiated to validate and exploit the use a state-of-the-art nucleic acid-based technique to investigate the diversity of fungal species in a range of substrates representing peat (13 samples), composted green waste (9), woodfibre (6), coir (6) and bark (4). In all twenty-nine different species of fungi were identified in the 38 substrates tested, of which the majority (Aspergillus, Chaetomium, Mortierella, Mucor, Penicillium, Verticillium and other species) were benign saprotrophic organisms. Beneficial Trichoderma species (T. asperellum, T. harzianum and T. viride) were present in nine samples, mostly peats. Only two of the samples contained fungi that might be regarded as a potential threat to plant health, Fusarium oxypsorum f.sp. melonis, a pathogen of melons, and a species of Rhizoctonia pathogenic to barley and lupins. R. solani was demonstrably absent in all and so was the clubroot organism, Plasmodiophora brassicae, whose presence was also rigorously investigated using a sensitive antibody and PCR-based technique. This study has shown that modern molecular techniques can be used to provide a comprehensive assessment of contamination of growing media constituents, particularly by fungi such as F. oxysporum and other commercially significant organisms such as the plant pathogen P. brassicae. As a result of this study the technique is now being offered commercially.
Peats which are more decomposed may have a greater buffering capacity and therefore be more stable with regard to pH and physical structure than younger peats. Peats from three sources, Ireland (H5 on the von Post scale), Latvia (H2) and Lithuania (H2) in combination with three rates of dolomitic lime (2, 3 and 4 kg m-3) were studied for their effect on pH and stability of the growing medium and on the growth of Hebe pinguifolia 'Sutherlandii' over a period of one year. Two experiments were conducted in ebb and flood benches: one irrigated with hard (325 mg L-1 bicarbonate) water and the second with rainwater (zero bicarbonate). With soft water, pH in the H5 peat declined gradually while it was stable in the H2 peats. Where hard water was used, pH rose sharply in the second half of the experiment but much less in the H5 than in the H2 peats. At the low rate of lime, shrinkage of the growing medium was similar for all three peats but higher lime rates increased shrinkage in the H2 peats. The Lithuanian (H2) peat produced the heaviest plants at a lime rate of 2 kg m-3 but at 4 kg m-3 fresh weight was greatest in the H5 peat. Growing medium shrinkage was significantly and positively related to the pH of the medium towards the end of the experiments. Plant fresh weight was significantly and negatively related to growing medium shrinkage and to pH.
Most of the waste collected in sub-Saharan African cities is biodegradable but it is usually dumped in landfills, creating environmental and health challenges for residents. However, there are biodegradable waste treatment methods that could mitigate these challenges. This study analysed anaerobic digestion, composting, vermicomposting and fly larvae waste treatments using life cycle assessment (LCA). The impact categories assessed were energy use, global warming and eutrophication potential. The results showed that anaerobic digestion performed best in all impact categories assessed. However, management of the anaerobic digestion process is critical and methane losses must be kept very small, as otherwise they will cause global warming.
Compost amendments to soils can minimize losses from soilborne plant pathogens, yet the mechanisms by which this occurs have not been well elucidated. In the present study, developmental responses of Pythium aphanidermatum zoosporangia to vermicomposts were observed to better understand how suppression of Pythium seedling disease is expressed. Mature zoosporangia were exposed to vermicompost extracts (VCEs) and monitored using time-lapse photomicroscopy. Sterile and nonsterile VCEs inhibited indirect germination and viable zoospore production whereas zoosporangia germinated directly in VCE to produce germ tubes. Additional treatments were tested to determine factors that promote direct over indirect germination. The pH (5 to 9 at 0.001 M) and ionic strength (0.1 to 0.0001 at pH 6) of potassium phosphate buffer did not alter zoosporogenesis compared with sterile water. Decreasing osmotic potentials in glucose and sucrose from -248 to -2,712 kPa or in polyethylene glycol 8000 from -0.335 to -105 kPa led to a decrease in indirect germination with a corresponding increase in direct germination. Significant levels of seed infection were observed within 1 h of exposure to zoospores (produced in sterile water) or to germ tubes (produced in sucrose solution). Our data demonstrate that VCEs suppress zoosporogenesis and stimulate direct germination; however, this did not result in the suppression of germ tube growth and seed infection.
Consumer demand for fresh market organic produce combined with the increasing market share of ready-to-eat products indicates the potential for expansion of an organic culinary herb market. Barriers to organic herb greenhouse production are high as a result of lack of available technical information and the low number of producers experienced in this area. There is a critical need for information and technologies to improve the management of organic soil and fertilizer amendments to optimize crop yields and quality, manage production costs, and minimize the risk from groundwater nitrogen (N) contamination. Because of limited information specific to organic culinary herb production, literature on organic vegetable transplants and conventional basil (Ocimum basilicum) production was also considered in this review. Managing N for organic crops is problematic as a result of the challenge of synchronizing mineralization from organic fertilizer sources with crop N demand. A combination of materials, including locally formulated composts, supplemented with standardized commercially formulated fertilizer products is one method to ensure crops have access to mineral N throughout their development. In experimental greenhouse systems, local raw materials are frequently used as media amendments to satisfy partial or complete crop fertility requirements. This makes comparisons among experiments difficult as a result of the wide variety of raw materials used and the frequent interactions of fertilizer source and planting media on nutrient availability. Nitrogen mineralization rates are also influenced by additional factors such as the environmental conditions in the greenhouse and physical and chemical properties of the media and fertilizer. Despite the variability within and among experimental trials, yields and quality of organically grown crops are frequently similar to, and occasionally better than, conventionally grown crops.
BACKGROUND: Using proper growing medium is known to be an effective way to improve crop growth and yield. However, the effects of growing media on geranium essential oil have scarcely ever been examined in detail. In this research, the effects of different growing media (soil, sand, pumice, perlite and perlite + cocopeat) on growth, oil yield and composition of geranium have been studied.
RESULTS: Growth was significantly improved in soilless grown plants compared with that in soil grown plants. Oil yield of soilless grown plants (except for pumice) was about three-fold higher than that in soil grown plants. The increase in oil yield was correlated with higher leaf dry weight (r2=0.96), as oil content was not affected. The citronellol/geranium ratio of oil clearly affected by growing media changing from 5:1 in soil culture to 3:1 in soilless culture which is more acceptable for perfumery.
CONCLUSION: Compared with soil, soilless media could produce higher yield of high-quality geranium oil that fits market requirements. Growth, oil yield and composition of plants grown in sand (a cheap and abundant growing medium) was not significantly different from those in perlite and perlite + cocopeat.
Keywords: Pelargonium graveolens L.; soil culture; soilless culture; citronellol; geraniol
During the past 20 years, the Ornamental Nursery Research Program at the former Horticultural Research Institute of Ontario (now part of the University of Guelph) has been conducting applied research dealing with environmentally friendly and sustainable nursery production practices with emphasis on container production. The use of farm, industrial, and consumer waste by-products as amendments in nursery substrates has been a major focus. The program has evaluated hundreds of potting mixes derived from individual or combined, raw or composted waste by-products including spent mushroom compost, turkey litter compost, paper mill sludge, municipal waste compost, corrugated cardboard, apple pomace, wood chips from pallets, pulverized glass, and various types of tree barks. With few exceptions, all the above waste by-products tested under our cultural conditions provided acceptable to excellent container-growing media, often in amounts exceeding 50% and sometimes up to 100% by volume in No. 2 containers (6 L), even despite initially elevated and potentially toxic contents of soluble salts [expressed in terms of electrical conductivity measured up to 8.9 dS·m-1 in 1 substrate : 2 water (by volume) extracts] in many of the substrates. A key to these successful results is that salts leach quickly from the containers to benign levels (∼1.0 dS·m-1) with normal irrigation practices. High initial pH in most waste-derived substrates (up to 8.9) has had little or no discernible effect on growth of a wide assortment of deciduous nursery species. By-products such as paper mill sludge and municipal waste compost with soluble salts contents typically ranging from 0.8 to 2.0 dS·m-1, also provide acceptable rooting media provided salts are leached before use to values ≤0.2 dS·m -1. The porosity and aeration characteristics of waste-derived substrates tend to be comparable to, or better than, those of bark.
Peat replacement is an issue that receives much attention in the horticulturist agenda. Several organic materials have been suggested either as substrates or as substrate constituents. This study aims to determine how three such materials, one compost and two vermicomposts, affect the rooting of cuttings and plant growth of rosemary plants grown in pots. The compost (C) and vermicomposts (V1 and V2) were obtained from the same batch of tomato crop waste. Each material was mixed with peat at several proportions. Two experiments were carried out in nursery conditions. In the first, rosemary cuttings were grown in each mix and rooting was quantified. In the second experiment, rooted seedlings were grown in each mix to marketable size (six months after the seedling transplant). The physical, physico-chemical and chemical characteristics of the initial mixes and of the mixes at the end of the six-month experiment were determined. The physical properties of the substrates were within adequate ranges. pH was fairly alkaline, especially in C and salinity was particularly high in the C-based mixes. Soluble mineral contents in C were much higher than in V1, V2 or peat. Mixing with peat produced substrates with intermediate characteristics. Both vermicomposts outperformed compost and peat for rooting cuttings. The presence of hormone-like substances in the vermicomposts might be behind this effect. The vermicompost-based substrates gave acceptable results for growing plants, though none performed as well as the control. Nitrogen and potassium contents in cuttings and ready-for-sale plants were low and phosphorus content was very low compared to sufficiency ranges, which led to a recommendation to increase fertilization. At the end of the six-month experiment, the mix properties had changed, representing an improvement in the substrate quality that might be taken into consideration when transplanting the rosemary to the soil.
Accumulation of cadmium (Cd), lead (Pb), zinc (Zn), copper (Cu) and manganese (Mn) in roots, stems and leaves of fenugreek and tomato grown on lateritic soil amended with municipal solid waste, market and floral waste, and their composts and vermicomposts prepared using three earthworm species, were assessed. The heavy metal accumulation in the plant parts showed significant correlations with that of their respective inputs (p < 0.001). This accumulation in root, stem and leaves of the plants were significantly different across different treatment inputs and sole soil (p < 0.05). The accumulation was higher in tomato than that of fenugreek. The metal accumulation in different plant parts was in ranking order of stem > root > leaf in case of Cd; root > stem > leaf in case of Zn, Pb and Cu; and leaf > stem > root in case of Mn in both the plants. The Bioaccumulation Coefficient was less than a unity for the metals in tomato and fenugreek. However, the Bio-Transfer Coefficient was more than a unity in Cd and Mn while it was reverse for Pb, Zn and Cu for both the plants.
Three composts were used as plant growing media: green and pruning wastes compost (GPC) and vermicompost (GPV) and slumgum compost (SLC). Their main physico-chemical and biological characteristics were studied and nine growth substrates were prepared in order to establish production essays for rosemary, Leyland cypress, lettuce, onion, petunia, and pansy. GPC compost and GPV vermicompost had excellent physico-chemical characteristics, allowing them to be considered good substrates. The high E.C. and the low GI values for SLC means that it should not be used in high proportions. However, the high concentration of N could permit its use in suitable fertilizers, especially in Leyland cypress. Rosemary, lettuce and onion were seen the more sensitive species to high dosage of compost. Leyland cypress, petunia and pansies recorded good growth rates with high GPC dosage. Finally, GPV, at a proportion of 25% of the substrate, could be a good sustainable practice for plant production.
A comparative study on the suitability of one compost and two vermicomposts, obtained from the same batch of tomato-crop waste, as growth media for ornamental plant production was carried out. Each material was mixed with Sphagnum peat at 100 : 0, 75 : 25, 50 : 50, 25 : 75, and 0 : 100 (peat control) proportions by volume. Two ornamentals (Calendula officinalis, Viola cornuta) were sown and grown in the 13 substrates. Substrates were characterized physically and chemically. Seed germination, total leaf chlorophyll (SPAD units), plant growth, and plant nutrient concentrations were determined. The compost and the vermicomposts were markedly different from peat. Compost and the vermicomposts had greater bulk density and lower total porosity than peat. Compost had larger aeration and lower water-holding capacity than vermicomposts and peat. Compost and vermicomposts were alkaline (pH = 8.8 on average) whilst peat was acidic (pH = 5.9). Electrical conductivity was low in peat (0.23 dS m–1) and vermicomposts (0.65 dS m–1), and high in compost (2.85 dS m–1) due to the high concentrations of K+ and SO. Mixing compost and vermicomposts with peat produced substrates with intermediate characteristics. Physical properties were within adequate range for all mixes except for the compost ones. pH was within adequate range only in pure peat, and salinity was extremely high in the compost mixes. Compost was phytotoxic, as shown by the strong reduction of seed germination, chlorophyll content, and plant growth of both ornamentals. Vermicomposts did not affect seed germination but reduced plant growth, though much less than compost. Mixing these materials with peat improved germination and growth. The diluted materials (compost at the 25 : 75 and vermicomposts at the 50 : 50 and 25 : 75 proportions) produced good-quality plants.
This study examined the feasibility of using biochar substrate made from green waste in place of some or all of the original peat substrate (OP) commonly used for the cultivation of the ornamental plant Calathea rotundifola cv. Fasciata. The three growing media were OP (100%), BGW (100%), and OP + BGW (50% each). BGW reduced media degradation; at the end of the 6-month experiment, the fraction of particles >1 mm was decreased by 39%, 9%, and 21% in OP, BGW, and OP + BGW, respectively. Plant growth was greatest with OP + BGW; total biomass, for example, increased by 22% in OP + BGW relative to peat alone. The results indicate that, in addition to reducing green waste, biochar generates a product that can be used as a partial substitute for peat in the cultivation of C. rotundifola cv. Fasciata. The addition of BGW products to plant growth media may reduce the rate at which the media decomposes and therefore increase media longevity.
Dutch greenhouse growers are obliged to invest in environmental friendly cropping systems, in order to comply with new legislation. Closed soilless growing systems may lead to environmental friendly systems and thus to a sustainable horticultural sector. This paper encompasses the change from general to specific legislation, the availability of good water and the developments in disinfection of nutrient solutions. For the latter, the interest of growers in the possibilities of slow sand filtration to disinfect the nutrient solution will be discussed.
Annual production of crop residues has reached nearly 4 billion metric tons globally. Retention of this large amount of residues on agricultural land can be beneficial to soil C sequestration. Such potential impacts, however, may be offset if residue retention substantially increases soil emissions of N2O, a potent greenhouse gas and ozone depletion substance. Residue effects on soil N2O emissions have gained considerable attention since early 1990s; yet, it is still a great challenge to predict the magnitude and direction of soil N2O emissions following residue amendment. Here, we used a meta-analysis to assess residue impacts on soil N2O emissions in relation to soil and residue attributes, i.e., soil pH, soil texture, soil water content, residue C and N input, and residue C:N ratio. Residue effects were negatively associated with C:N ratios, but generally residue amendment could not reduce soil N2O emissions, even for C:N ratios well above ca. 30, the threshold for net N immobilization. Residue effects were also comparable to, if not greater than, those of synthetic N fertilizers. In addition, residue effects on soil N2O emissions were positively related to the amounts of residue C input as well as residue effects on soil CO2 respiration. Furthermore, most significant and stimulatory effects occurred at 60-90% soil water-filled pore space and soil pH 7.1-7.8. Stimulatory effects were also present for all soil textures except sand or clay content 10%. However, inhibitory effects were found for soils with >90% water-filled pore space. Altogether, our meta-analysis suggests that crop residues played roles beyond N supply for N2O production. Perhaps, by stimulating microbial respiration, crop residues enhanced oxygen depletion and therefore promoted anaerobic conditions for denitrification and N2O production. Our meta-analysis highlights the necessity to connect the quantity and quality of crop residues with soil properties for predicting soil N2O emissions.
The use of composts from distillery wastes as alternative growing media ingredients for transplant production instead of peat, whose harvesting constitutes a severe environmental damage, was studied. Two composts were prepared with exhausted grape marc and cattle manure (C1), and with exhausted grape marc and poultry manure (C2). Four vegetable species, lettuce (Lactuca sativa), chard (Beta vulgaris), broccoli (Brassica oleracea) and coriander (Coriandrum sativum) were grown. Nine substrates were compared: limed white peat (control); compost C1; compost C2; and six mixtures containing 25%, 50% and 75% by volume of each compost with the corresponding peat as diluent. The germination and the effects on the transplant morphological and nutritional aspects of the different mixtures peat/compost considered were studied. All media elaborated showed adequate physical, physico-chemical and chemical properties compared to peat for their use as growing media in horticulture, being these two composts suitable ingredients for the partial substitution of peat, in quantities of 25–50% by volume, without causing any loss in the yield and in the results obtained for the nutritional status when compared to those obtained using the control.
An inventory of materials suitable for use as growing media for ornamental potted plant production in Spain has been prepared. Special attention has been paid to solid organic wastes generated by production, industrial and consumer activities. Information obtained from this study has been organised into two data bases. Data base 1 contains the “General Characteristics” file of more than 105 materials. In this file, data are available regarding generation points, material availability, uses, cost, disposal expenses, etc. Data base 2 is comprised of the “Specific Properties” file of 63 materials selected from data base 1. The main physical, chemical and biological properties of these materials as container media have been characterised, and the results obtained have been compiled. Finally, a computerised data bank has been created which can be found in the home page of the Spanish Ministry of Agriculture, Fisheries and Food (http://agritel2.mapya.es/sustratos/).
Municipal Solid Waste (MSW) management is one of the most vital issues in the contemporary urban environments particularly in developing countries. Various aspects of MSW management in Puducherry, a small erstwhile French colony in Pondicherry Union Territory were assessed in order to improve the management practices. Its per capita generation rate and quantity in the city showed gradually increasing trend with passage of years. It was 265 tonnes/day (t/d) during 2003, which increased to 370 t/d in 2008, with a waste generation factor of 0.59 kg/capita/day. The sources of MSW classified into different categories and sub-categories showed domestic waste including kitchen waste, market waste, garden and agricultural waste, hospital waste, road and construction waste, sweeping and sanitary waste. Samples of MSW collected randomly from the main dumping yard at Karuvadikuppam in Puducherry, were categorized into biodegradable waste comprising 65% and non-biodegradable waste comprising 35%. MSW is dominated by yard waste (38.4%) followed by paper (30%) and plastics (10.4%) and the remaining 21.2% comprised of other waste. The municipalities in Puducherry adopted different methods such as door-to-door collection with segregation of garbage at source for effective MSW management. Composting of the organic waste included both aerobic composting and vermi-composting, and non-biodegradable waste was picked up and recycled for the final disposal of MSW. Awareness programs educating people regarding the problems as well as significance of MSW disposal were practiced through NGOs. However, it was found that there are some shortcomings in the existing MSW management practices, which need rectification.
Compost produced from biological treatment of organic waste has a potential for substituting peat in growth media preparation. The life-cycle-inventories (LCIs) of the two alternatives were compared using LCA-modelling (EASEWASTE) considering a 100-year period and a volumetric substitution ratio of 1:1. For the compost alternative, the composting process, growth media use, and offsetting of mineral fertilizers were considered. For the peat alternative, peatland preparation, excavation, transportation, and growth media use were considered. It was assumed that for compost 14% of the initial carbon was left in the soil after 100 years, while all carbon in peat was mineralized. With respect to greenhouse gas emissions, the former is considered a saving, while the later is considered an emission, because peat in a peatland is considered stored biogenic carbon. The leaching during the growth media use was assessed by means of batch leaching tests involving 4 compost samples and 7 peat samples. The compost leached 3–20 times more heavy metals and other compounds than the peat. The life-cycle-assessment showed that compost performs better regarding global warming (savings in the range of 70–150 kg CO2-eq. Mg−1) and nutrient enrichment (savings in the range of 1.7–6.8 kg NO3 Mg−1 compost), while peat performs better in some toxic categories, because of the lower content of heavy metals.
The bulk density, total porosity, air porosity and water-holding capacity of mixtures of equal parts of either sand or scoria with peat moss, pinebark, poppy straw and sawdust can be predicted from the respective properties of the ingredients. Total porosity of the media was inversely correlated to bulk density, but there is no clear correlation between air porosity and bulk density. Air porosity increased with pot size.
Salinity and porosity of composted sewage sludge (CSS) were studied to evaluate their effect on vegetable seedlings, specifically on vegetable seedling performance and toxicity threshold of soluble salts. For the evaluation, CSS was mixed with different proportions of leached CSS to control the salinity. Soluble salt content of 1.45% or higher in growth media inhibited the growth of cucumber, tomato, and pepper seedlings, while that of 1.1% was relatively safe. Different porosities of CSS media were prepared by mixing CSS (<10 mm) with ground CSS (<1 mm) in different proportions (CSS and ground CSS were leached beforehand to prevent salt stress). The vegetable seedlings grew well in CSS media without showing symptoms of growth inhibition if the total porosity ranged from 66% to 81% and the water holding porosity ranged from 48% to 59%. However, the best seedling performances were achieved with the coarser media with high total porosities. The study indicated that when salt content was appropriate, CSS can be used alone as a vegetable seedling growth medium without the need for grinding or blending with other materials.
We successfully co-composted catering waste with green waste and shredded paper to yield two high-nitrogen composts for use in horticulture. Sunflowers (Helianthus annuus L.) were grown in various mixtures of the compost and a commercially available peat-based compost to assess the efficacy of catering waste-based composts for peat replacement. Height, head diameter, seed mass and above-ground biomass were measured, with all mixtures giving a significant increase in yield or size over the commercially available peat-free control compost. We conclude that differences in physical structure governed sunflower growth over substrate chemistry, and none of the compost mixtures were nutrient deficient. We recommend that catering waste co-compost can be substituted to at least 75% within Sphagnum-based traditional growing media, providing a viable replacement for a large proportion of peat used as a growth medium in the horticulture industry. Our catering waste compost yielded similar seed head, seed mass and above-ground biomass values to 100% peat-based compost in all food waste compost blends tested in this study.
Bacterial communities and chitinase gene diversity of vermicompost (VC) were investigated to clarify the influence of earthworms on the inhibition of plant pathogenic fungi in VC. The spore germination of Fusarium moniliforme was reduced in VC aqueous extracts prepared from paper sludge and dairy sludge (fresh sludge, FS). The bacterial communities were examined by culture-dependent and -independent analyses. Unique clones selected from 16S rRNA libraries of FS and VC on the basis of restriction fragment length polymorphism (RFLP) fell into the major lineages of the domain bacteria Proteobacteria, Bacteroidetes, Verrucomicrobia, Actinobacteria and Firmicutes. Among culture isolates, Actinobacteria dominated in VC, while almost equal numbers of Actinobacteria and Proteobacteria were present in FS. Analysis of chitinolytic isolates and chitinase gene diversity revealed that chitinolytic bacterial communities were enriched in VC. Populations of bacteria that inhibited plant fungal pathogens were higher in VC than in FS and particularly chitinolytic isolates were most active against the target fungi.