Green Manure Management Research Articles

Utilization of Diversified Cover Crops as Green Manure-Enhanced Soil Organic Carbon, Nutrient Transformation, Microbial Activity, and Maize Growth

Studying green manure in several returning methods to enhance soil fertility and crop benefits is a strong foundation for cropland nutrient management. However, how different types of green manures and their variable doses affect the efficacy of applied manures, either buried or mulched, remain overlooked. The objective of this study was to optimize green manure management to enhance soil fertility and maize biomass using five types of green manures (white mustard, forest rye, fiddleneck, sufflower, and pea) in two different doses (low, 5 g per pot, and high, 10 g per pot), which were either buried or mulched before and after maize sowing. Results revealed that total carbon content increased due to green manure treatments, representing a 10% increase over control, particularly through buried w. mustard (10% increase before maize cultivation) and mulched safflower and pea (12% and 11% increase after maize cultivation over control). Dry maize aboveground biomass yields also improved across all variants, with buried mustard yielding 18.4 g·plant−1 (compared to 8.6 g·plant−1 in the control), mulched mustard yielding 16.4 g·plant−1, and buried pea yielding 17.8 g·plant−1. Green mulching generally acidified the soil (pH 5.71 compared to 6.21 in the control), except for buried fiddleneck (pH 6.39 after maize cultivation) at a high dose of manures. Carbon-mineralizing enzyme activities (dehydrogenase and β-glucosidase) were significantly increased by green manures, with buried fiddleneck showing a 22.6% and 20.6% increase over the control, and mulched fiddleneck showing a 24.5% and 22.4% increase under high doses. The study suggests that partially decomposed and mineralized mulched biomass may induce a negative priming effect on carbon-mineralizing enzymes due to a decrease in the C/N ratio of the soil. It emphasizes that the nutrient content and stoichiometry of green manures, alongside soil characteristics such as the C/N ratio, are critical factors for sustainable soil management and carbon sequestration. These findings underscore the need for careful selection and management of green manures to optimize soil health and carbon-storage outcomes.

No-tillage with total green manure incorporation: A better strategy to higher maize yield and nitrogen uptake in arid irrigation areas

The efficacy of integrating green manure in arid irrigation regions to enhance maize yield and nitrogen (N) uptake efficiency has been extensively explored. However, limited research has delineated the contribution of green manure N versus soil N on crop N utilization efficiency. This study integrated field experiments with micro-plot experiments to examine green manure (common vetch) management practices for achieving high maize yield and N uptake. In a micro-plot experiment, 15N technology was utilized to label green manure crops. Five treatments were applied in the research methodology: conventional tillage without green manure as the control (CT); tillage with total green manure incorporation (TG); no-tillage with total green manure mulching (NTG); tillage with only root incorporation (T); and no-tillage with removal of above-ground green manure (NT). The results in the micro-plot experiment were the same in the field, and both demonstrated that the utilization of green manure led to a substantial increase in maize yield and nitrogen uptake efficiency (NUPE) compared to conventional tillage (CT). In particular, under NTG, N uptake by maize from green manure was higher than NT and T, accounting for 59.1% of maize N uptake. Furthermore, the application of NTG boosted the NUPE of soil N in maize to 50.7%, which is higher than TG by 5.5%. Meanwhile, it decreased the proportion of soil N in the maize. The difference between NTG and TG was primarily shown in the maize grains. For N transport in the soil, NTG decreased N loss while increasing soil N retention. Also, it facilitated the mineralization of soil organic N before the flowering stage. In conclusion, the adoption of no-tillage with total green manure mulching not only increased N uptake both from green manure and the soil but also decreased the proportion of soil-derived N in maize.

Agroecological Transformation: Implementation of an Agroforestry System in a Construction Debris Area Focusing on Vegetables Development through Microbial Treatments

Soil microorganisms play an important role on plant development and the homogenization of soil microbiomes is harmful to agri-environments. It is essential that agricultural practices are carried out by taking soil microbiome preservation in consideration. Agroforestry systems are one of the most environmentally friendly agrosystems and its plant diversity directly influences the soil microbiome diversity. In this study, we tested the efficacy of the microbial consortium (MC) obtained from compost and the cyanobacteria Arthrospira platensis (Ap) compared with the application of the vermicompost tea (VT) and bokashi (Bk) in arugula, lettuce, beetroot, and carrot in two seasons in a recently implemented agroforestry system. We aimed to verify if MC and Ap could be new promising sustainable alternatives in vegetables production. The strategy can be broken down into three stages: (1) Green manure management: planting, cutting, griding, and incorporation in the soil, (2) agroforestry system implementation, and (3) treatment application in a completely randomized blocks design. The vegetables yield was measured. Nutritional traits and the plant root system were evaluated for arugula and lettuce. Greater plant yield, nutritional values, and plant root development were observed in the MC-treated plants; Ap and Bk had, in general, similar results. Our data show that both MC and Ap have potential to become a sustainable product for agricultural production.

How do green manure management practices affect ammonia emissions from maize fields?

The use of “green manure”—crops that are cultivated specifically to be incorporated into the soil to increase its organic matter content—has been proposed as an alternative to chemical fertilizer because of its benefits in terms of crop yield. Nonetheless, the differential impacts of green manure on ammonia volatilization remains underexplored. In this study, the influence of various green manure management strategies on ammonia volatilization in maize cultivation were examined. Field experiments conducted from 2020 to 2022, the field experiment applied common vetch after the spring wheat harvest, with five distinct treatments: conventional tillage without green manures as a control (CT); tillage with total green manure incorporation (TG); no-tillage with total green manure mulching (NTG); tillage with only root incorporation (T); and no-tillage with removal of aboveground green manure (NT). The results showed that under TG and NTG, the maize yields were 12.3%-33.2% higher than under CT, and 6.8%-18.8% higher than under T and NT. Compared with CT, all four green manure management practices also significantly increased NH3 emissions in maize fields, and they increased ammonia volatilization by 12.0%-13.7% in NTG and TG compared to root retention patterns, with NTG exhibiting higher rates than TG. NTG significantly increased soil organic matter, total nitrogen, mineral nitrogen, water-filled pore space (WFPS), microbial biomass carbon and nitrogen, and C: N, and it decreased soil pH compared to TG. Regression analysis showed that these factors were correlated with NH3 volatilization. In addition, soil urease and ammonia-oxidation functional genes (amoA) showed differences under green manure management practices. Structural equation modeling showed that NH4+-N had the greatest positive impact on NH3, and urease activity and total nitrogen had positive effects on NH4+-N. Furthermore, microbial biomass carbon and pH had positive and negative effects on urease activity, respectively, both of which were only related to SOM. At the same time, WFPS had a positive impact on total nitrogen. In summary, no-tillage with total green manure mulching increases maize yield but also increases NH3 emissions. NH4+-N formed by the hydrolysis of urea by soil urease and the conversion of total nitrogen were found to be the main reasons for high NH3 emissions. In addition, SOM can promote urease activity, increase NH4+-N content and NH3 volatilization by increasing MBC and decreasing soil pH.

Evaluation of farmland soil health and optimization of evaluation system under different green manure applications in a semi‐arid irrigation area

AbstractHealthy soil is essential for maintaining food security and enhancing ecosystem functions. Green manure application improves soil fertility and is an alternative to chemical fertilizers; however, research on optimizing soil health assessment systems and providing comprehensive and accurate information for local farmland green manure management models remains limited. In this study, we used maize and potato intercropped with green manure farmland in the main crop production area of a semi‐arid irrigation area in Northwest China as the research object, integrated the regional soil environment characteristics, and used principal component analysis and other methods to establish a minimum index data set including physicochemical, biological, and yield indices. A soil health assessment system applicable to the study region was constructed and optimized by drawing the scoring curve. The results showed that green manure treatment exerted a positive effect on the soil bulk density, nutrient content, extracellular enzyme activity, and the yield of maize and potato fields. This evaluation method showed that both green manure treatments could improve the soil health index of two major crop fields, with scores of 6.9 (3.7–8.6) and 6.2 (4.5–7.0) for maize and potato farmland, respectively, with a greater positive effect caused on maize. This evaluation system can not only reflect the soil conditions of farmland accurately given the application of green manure in the semi‐arid irrigation areas of northwest China but also provide reference for the promotion of organic fertilizers such as green manure and the resolution of regional soil health differences.

No-tillage with total green manure mulching: A strategy to lower N2O emissions

ContextGreen manure application in agricultural soil is known to enhance nitrogen use efficiency and crop yield. However, limited research exists on the potential effects of green manure returning on N2O emissions. ObjectiveThis study aims to investigate the effects and underlying mechanisms of N2O emissions in maize fields under different green manure management practices. MethodsA field experiment was conducted using common vetch as a green manure crop following the harvest of spring wheat. The study employed a completely randomized block design and examined four treatments: tillage with total green manure incorporation, no-tillage with total green manure mulching (NTG), tillage with green manure root incorporation (T), and no-tillage with aboveground green manure removal (NT). The study explored both non-biological and biological factors affecting nitrogen conversion to elucidate the mechanisms in N2O emissions. ResultsN2O emissions were 17.7% lower in TG and NTG compared to T and NT (P < 0.01), with NTG showing a 12.2% reduction compared to TG (P < 0.05). NTG also exhibited the lowest average N2O fluxes at 24.2 μg N m−2 h−1. In terms of non-biological factors, N2O emissions were negatively correlated only with aggregate NH4+-N and NO3－-N (P < 0.05). Despite increasing soil mineral nitrogen, NTG had approximately 72.3%− 92.4% of it in the form of aggregate nitrogen. In addition, under NTG, the aggregates have better structure and stability. q-PCR analysis revealed higher nos Z gene abundance in NTG than in other treatments (P < 0.05). Regression analysis showed that N2O emissions were negatively correlated with nos Z's abundance and N2O reductase diversity (P < 0.05). ConclusionsNo-tillage with total green manure mulching (NTG) effectively reduced N2O emissions by enhancing mineral nitrogen in soil aggregates and increasing the abundance of the nos Z gene. ImplicationsOur findings offer valuable insights for long-term agricultural management strategies aimed at improving nitrogen retention and mitigating climate change impacts.

Impact of Crop Residue and Green Manure Management in Rice Crop on Soil Nutrient Dynamics in Tarai Belt of Shivalik Himalaya, India

The study explores the effects of different soil management practices on various soil properties within the Tarai Belt of the Shivalik Himalaya region to assess the effects of different nutrient management strategies on various soil properties in the context of rice cultivation. Ten treatments were employed, T1 (100% recommended dose of NPK fertilizers), T2 (50% crop residue + 50% recommended NPK dose), T3 (50% crop residue + 50% recommended NPK dose with the addition of Pusa decomposer), T4 (50% crop residue + 50% Green Manure (GM), T5 (50% crop residue + 50% GM with Pusa decomposer), T6 (Crop residue at 2.5 tons per hectare + Pusa decomposer), T7 (Crop residue at 2.5 tons per hectare without Pusa decomposer), T8 (Absolute control group with no fertilizer application), T9 (150% recommended NPK dose), and T10 (100% recommended NPK dose with the addition of Farm Yard Manure at a rate of 5 tons per hectare, along with Zinc and Boron supplementation). including varying combinations of crop residues, organic and inorganic fertilizers, and green manure. Soil properties examined included soil organic carbon, available nitrogen, available phosphorus, available potassium, pH, and electrical conductivity (EC) at two different soil depths (0-15 cm and 15-30 cm. Organic sources enhanced soil organic carbon, while inorganic sources notably improved the availability of nitrogen, phosphorus, and potassium. The results showed that treatments incorporating both organic and inorganic nutrient sources demonstrated improved soil health and nutrient availability, with treatment T9 (150% recommended dose of fertilizer, RDF) showing the best results, particularly in terms of available nitrogen, phosphorus, and potassium. However, the sustainability of this approach over the long term may be a concern. Treatment T10, which combined 100% RDF with farmyard manure, zinc, and boron supplementation, emerged as a promising alternative for sustainable soil management. Treatment T3, with the incorporation of crop residues and the application of Pusa decomposer, also showed potential for maintaining soil health. These findings emphasize the importance of a balanced approach to nutrient management that combines readily available nutrients from inorganic sources with the long-term benefits of organic matter.&#x0D; In summary, this study emphasizes the importance of integrated nutrient management and sustainable agricultural practices for enhancing soil fertility and overall soil health, thereby contributing to sustainable crop production. These findings hold significance for addressing soil nutrient imbalances and ensuring the well-being of farmers and environmental sustainability.

Interaction between dissolved organic carbon and fungal network governs carbon mineralization in paddy soil under co-incorporation of green manure and biochar.

Legume crops in rice cultivation are typically rotated and incorporated into the soil as green manure to improve soil fertility. Biochar has recently been co-incorporated with green manure to simultaneously stimulate soil organic carbon (SOC) mineralization and increase carbon (C) sequestration. However, few studies examine the effects of the co-incorporation of biochar and green manure on C cycling and the underlying microbial mechanisms in paddy fields. In this study, the effects of the co-incorporation of green manure and biochar on C mineralization, dissolved organic carbon (DOC) characteristics, and microbial community structures were investigated. A pot study was conducted with three treatments: inorganic NPK (NPK), inorganic NPK + green manure (GM), and inorganic NPK + green manure + biochar (GMC). Organic amendments significantly increased cumulative C mineralization, with amounts in the order GMC (3,434 mg·kg-1) > GM (2,934 mg·kg-1) > NPK (2,592 mg·kg-1). Fertilizer treatments had similar effects on DOC concentrations, with amounts in the order GMC (279 mg·kg-1) > GM (255 mg·kg-1) > NPK (193 mg·kg-1). According to fluorescence spectra, the highest microbial humic acid-like fraction and biological index were also in GMC. Co-incorporation of green manure and biochar shifted the composition of bacterial and fungal communities but more importantly, increased fungal network complexity and decreased bacterial network complexity. The increase in fungal network complexity with the increase in DOC concentrations and microbially derived components was the dominant factor in promoting C mineralization. Overall, this study reveals the underlying biochemical mechanism, the interaction between DOC and fungal network of C cycling in paddy soil under the co-incorporation of green manure and biochar management, and provides fundamental knowledge for exploring effective approaches to improve soil fertility and health in the future.

Soil management affects the nutraceutical properties of Primitivo's grape pomace

Soil management is a sustainable agronomic practice to produce grapes, wine, and grape pomace with a low environmental impact in viticulture, affecting soil microbial biodiversity, organic matter, and healthy roots. Grape pomace is the main by-product of winemaking and a valuable source of natural phytochemicals. This research aimed to evaluate the phenolic content and antioxidant activity of pomace deriving from the microvinification of the Primitivo wine grapes obtained by four different soil management techniques: cover crop (C), soil mechanical tillage (T), green manure (G) and farm soil management (F). The content of total phenolic compounds and anthocyanins in grapes and wines is the highest with the vineyard cover cropping system. Moreover, grape pomace derived by cover crop soil management shows a significant abundance of these molecules and a more elevated antioxidant activity than the other soil technique.

Tillage, green manure and residue retention improves aggregate-associated phosphorus fractions under rice\u2013wheat cropping

The sustainability of the rice–wheat system is threatened due to the deterioration of soil health and emergence of new challenges of climate change caused by low nutrient use efficiency and large scale burning of crop residues. The conservation agriculture based on tillage intensity, crop residue retention and raising green manuring (GM) crops during the intervening period between wheat harvest and rice establishment offers opportunities for restoration of phosphorus (P) dynamics and stimulate phosphatase activities within the macro-and micro-aggregates. Phosphorus and phosphatase activities in the soil aggregates affected by different residue management practices remain poorly understood. Thus, soil samples were obtained after a five-year field experiment to identify the effect of tillage, green manure and residue management on aggregate-associated phosphorus fractions. Four main plot treatments in rice included combination of wheat straw and GM were conventional till puddled transplanted rice (PTR) with no wheat straw (PTRW0), PTR with 25% wheat stubbles retained (PTRW25), PTR without wheat straw and GM (PTRW0 + GM), and PTR with wheat stubbles and GM (PTRW25 + GM). Three sub-plots treatments in the successive wheat crop were conventional tillage (CT) with rice straw removed (CTWR0), zero tillage (ZT) with rice straw removed (ZTWR0) and ZT with rice straw retained as surface mulch (ZTWR100). Results of the present study revealed significantly higher phosphorus fractions (HCl-P, NaHCO3-Pi and NaOH-Po) in treatment PTRW25 + GM and ZTWR100 compared with PTRW0/CTWR0 within both macro- and micro-aggregates. The total phosphorus (P), available P, alkaline phosphatase and phytin-P were significantly higher under ZTWR100 than CTWR0. The principal component analysis identified NaOH-Po, NaHCO3-Pi and HCl-P as the dominant and reliable indicators for evaluating P transformation within aggregates under conservation agriculture-based practices.

A Study on the Efficiency of Sustainable Wine Grape Vineyard Management Strategies

Crop protection strategies based on cupric products and mainly adopted in organic viticulture produce a consistent environmental impact due to the persistence of copper in soils and its negative effects on edaphic biodiversity. In this work, trials were carried out during the crop years 2018–2020 in a vineyard with an organic management by a low-copper strategy and in a conventional IPM management with an IPM strategy with reduced use of fungicides. Phytosanitary treatments have been strictly planned according to forecasting models, and fungicides have been partially substituted with substances improving the resistance mechanisms of plants. Different strategies of green manure management, in order to improve the health of vines, were also adopted. Results suggest the efficacy of the “GreenGrapes” plant protection strategy in conditions of low downy mildew pressure. Furthermore, no declines in the production quality have been recorded; conversely, the synergic effect of the green manure and the tested biostimulant substances (“GreenGrapes” protocols) and the green manure management improved yield and grape quality, compared with conventional conduction (IPM and Organic) with a grass covering.

Soil physical disturbance reduces maize growth, nutrition, and mycorrhiza formation in a green manure rotation with vetch

Green manure crops such as vetch (Vicia sativa L.) and their association with plant growth-promoting microorganisms like arbuscular mycorrhizal fungi (AMF) and diazotrophic bacteria are known to improve soil fertility and crop nutrition in agroecosystems. In a greenhouse pot experiment with a fully factorial design, we investigated the effects of green manure with vetch (incorporated or cut leaving the soil undisturbed), soil disturbance simulating a tillage event (without and with) and mineral fertilization (without and with NPK) on the abundance of available soil nutrients (NO3−, NH4+ and HPO42−), maize growth and nutrient content (N and P), and maize mycorrhiza formation by native AMF. First vetch was grown for 10 weeks and then left to mineralize for 12 weeks incorporated or not into the soil. Then before maize sowing, another soil-disturbance event was performed (with and without) and finally maize was grown for 18 weeks without and with NPK fertilization. Main results showed that the amount of soil NO3− and HPO42− increased substantially after the green manure mineralization before maize sowing, though with lower values after green manure soil incorporation, compared to that of the treatment without soil incorporation. Green manure soil incorporation reduced the final total maize dry weight biomass without NPK fertilization, but when combined with NPK green manure soil incorporation resulted in the highest final total maize dry weight biomass. However, type of green manure management had no effects on the other maize plant variables measured nor AMF root colonization. On the contrary, soil disturbance before maize sowing resulted in decreased AMF root colonization, cob dry weight, and cob N and P content. In conclusion, our results show that soil physical disturbance caused alterations in the plant-microbe-soil dynamics in the present vetch-maize rotation resulting in reduced maize growth, nutrition, and mycorrhiza formation.

Tillage, green manure and residue management accelerate soil carbon pools and hydrolytic enzymatic activities for conservation agriculture based rice-wheat systems

ABSTRACT We studied the effects of tillage, crop residues, and green manure on soil carbon pools and hydrolytic enzyme activity in a sandy loam after five cycles of the rice-wheat system (RWS). Four main plot treatments in rice were combinations of wheat straw and Sesbania green manure (GM) management: (1) puddled transplanted rice (PTR) with no wheat straw, (2) PTR with 25% wheat stubbles (12–15 cm long) retained, (3) PTR with no wheat straw plus GM, and (4) PTR with 25% wheat stubbles plus GM. Three subplots treatments in subsequent wheat were (1) conventional tillage with rice straw removed, (2) zero tillage (ZT) with rice straw removed, and (3) ZT with 100% rice straw retained as a surface mulch. The results showed that PTR with wheat stubbles retained plus GM and ZT wheat with rice straw retained (ZTWRS100) significantly (p< 0.05) increased all the carbon pools and hydrolytic enzymes except phenol oxidase and peroxidase activities. The carbon management index under ZTWRS100 retained was significantly higher than zero-till or conventional till wheat without residue. The principal component analysis identified active carbon, less labile carbon pools; xylanase and dehydrogenase hydrolytic enzymes as the most reliable sensitive indicators for assessing soil quality for conservation agriculture (CA) – based practices in RWS. The study showed that adoption of PTR with 25%-anchored wheat stubbles retained plus GM in rice followed by ZTWRS100 in wheat was the best crop production strategy for enhanced carbon pools, hydrolytic enzymatic activities and gives an idea of its overall fitness for carrying out ecosystem functions.

Species characterization and population dynamics of Hirschmanniella mucronata in lowland rice fields managed under conservation agriculture in Cambodia

The rice root nematodes, Hirschmanniella spp., are considered the predominant plant-parasitic nematode in the clay soils of Battambang’s lowland rice fields in Cambodia. In this study, we compared the nematode population dynamics, rice yield parameters, and soil organic matter content in lowland rice fields under conservation agriculture (CA) system with conventional tillage systems with green manure management (GMCT) or with plough-based tillage (CT) systems. Results demonstrated that GMCT for one year (GMCT1) and the long-term CA for seven years (CA7) reduced nematode densities in both soil and in rice roots, almost throughout the study period, compared to the CT. In the GMCT with tillage for two years (GMCT2), however, the Hirschmanniella spp. densities were high at the beginning, but reduced at later stages of the cycle. For rice yield components and soil fertility, CA7 proved to be effective in increasing plant height, the number of tillers/plant and soil organic matter. Based on molecular, morphometric and morphological features, the nematodes were identified as H. mucronata. The phylogenetic trees of three nuclear markers displayed similarity among 18S, 18S-ITS1-5.8S and D2D3 regions, identifying nematodes as H. mucronata clade I (bootstrap values of 79–100) and related to H. kwazuna and H. loofi sisters. Morphologically the long body (1,512–2,665 µm), long stylet (25–29 µm) and obvious mucron at the end of terminus matched with H. mucronata . Therefore, long term CA, with reduced tillage and using leguminous cover crops provides a promising system to control H. mucronata and promote rice yields and soil organic matter in Cambodian lowland rice fields.

СПОСОБЫ ИСПОЛЬЗОВАНИЯ ЗЕЛЕНОЙ МАССЫ ОЗИМОЙ ТРИТИКАЛЕ В КАЧЕСТВЕ УДОБРЕНИЯ В УСЛОВИЯХ СТЕПНОГО КРЫМА

The method of incorporating green leafy matter directly into the soil is called Green Manuring. Green Manuring helps improve soil quality in the following ways: increase organic content of soil, increase biological activity in the soil, improve agrochemical and agrophysical properties of the soil. The purpose of our research was to identify the influence of different ways of using green mass of winter triticale variety ‘Allegro’ on the soil fertility indicators before the sowing winter wheat under conditions of the steppe Crimea. Field experiments were carried out in 2015–2018. Soil – chernozem southern calcareous low humic. In the course of the research, we studied three ways of green manure management: disking at the phase of stem elongation, disking and ploughing at the phase of early heading, use of triticale biomass for forage (triticale stubble disking) – control variant. Specifically, the studies revealed that the most favorable conditions for obtaining seedlings of winter wheat were after the incorporation of plant biomass at the phase of stem elongation. In this case, plants consume moisture and nutrients more economically, organic matter mineralization occurs more actively. This method provided 2.01 mg/100 g of nitrate nitrogen in the root layer of the soil before sowing winter wheat exceeding the indicators by up to 40 % compared to other options of triticale biomass incorporation. Manuring Triticale aestivumforme at the phase of early heading increases the input of soil organic matter by 2.5–2.6 times compared to the stem elongation phase; by 3.9–4.0 times in case of use triticale biomass for forage. The full benefits of this technique will be seen in the subsequent years when the process of the organic matter mineralization will be completed. Option “use of triticale biomass for forage” ensured the least input of soil organic matter – 2.11 t/ha. Moreover, the content of nitrate nitrogen in the 0–30 cm soil layer decreased to 1.37, available forms of phosphorus – to 2.12 mg/100 g of soil. Besides, the production costs for incorporating 1 ton of organic matter into the soil increased by 5.3–5.6 times compared to green mass manuring.

A survey of green manure productivity on dryland organic grain farms in the eastern prairie region of Canada

Little is known about legume green manure productivity on organic farms. Soil and plant tissue were sampled in annual, biennial, and perennial green manures on 41 fields in the eastern prairies. Green manure biomass averaged 4572 kg ha−1; 53% was legume plant material and 18% was weeds. Soil test P and plant tissue P concentrations were below critical levels in about half of all green manures. Mean N fixation was estimated at 71 kg ha−1. This observational study provides a baseline for future research to optimize green manure and nutrient management in organic grain production systems.

Influence of green manure and rice straw management on soil organic carbon, enzyme activities, and rice yield in red paddy soil

Both the quantity and quality of organic amendments can influence the accumulation of soil organic carbon (SOC) and agroecosystem functioning. However, the evidences of the effect of combination of quantity and quality of organic amendments on the paddy soil quality and rice yield are scarce. An ongoing field experiment was conducted in Hunan province of China to investigate the effect of different Chinese milk vetch (Astragalus sinicus L.) and rice (Oryza sativa L.) straw management practices on the soil biochemical properties and rice yield. The experiment consisted six treatments: applying Chinese milk vetch (MV), applying early-season rice straw (S), applying early-season and late-season rice straw (DS), applying Chinese milk vetch and early-season rice straw (SMV), applying Chinese milk vetch, early-season and late-season rice straw (DSMV), and unamended organic amendment (CK). Compared with CK, SOC content was significantly increased by 13.0%, 18.5%, 11.1%, 12.3%, and 23.0% for the MV, S, DS, SMV, and DSMV treatments, respectively. No significant correlation was found between SOC content and yearly carbon inputs. Application of organic amendments increased soil hydrolase activities (β-D-cellobiosidase, β-1,4-glucosidase, β-1,4-xylosidase, β-1,4-N-acetyl-glucosaminidase and phosphatase). The geometric mean of the assayed hydrolases followed the order: S > DSMV > SMV > DS > MV > CK. Phenol oxidase was significantly higher in CK than in the applied organic amendment treatments. The lowest ratio of β-1,4-glucosidase: phenol oxidase occurred in the S treatment, suggesting that S treatment decreased microbial substrate use efficiency. The yearly average rice yield was increased by 18.6%, 8.5%, 12.3%, 14.6%, and 24.1% for MV, S, DS, SMV, and DSMV treatment with respect to CK. There was no significant correlation between SOC content and rice yield. In general, after 4-year cultivation, our results highlight the effect of quality of organic amendments on the chemical properties of SOC and its nutrient supply. Applying high quantities of diverse organic amendments is suggested to increase SOC content and rice yield in red paddy soil.

Energy flows in European organic vegetable systems: Effects of the introduction and management of agroecological service crops

Reducing inputs by promoting the recycling of energy within a cropping system is one of the principles of organic farming. To this end, the introduction and proper management of agroecological service crops (ASC) can play a key role. Few studies have analysed the effect of ASC introduction and compared energy flows under green manure (ASC-GM) and no-till roller crimper (ASC-NT) management. Moreover, current energy flows studies do not account for all the sources of energy that could be recycled within a cropping system, and none of them have evaluated the efficiency of cropping systems for recycling energy.Our study, which gathered information on eight field experiments across six European countries over two years, indicates that ASC inclusion and management required, on average, a 19.73% higher input investment than systems that did not include them. Nevertheless, ASC management strategies were more prone to increase the energy that potentially could be recycled within the cropping system. Moreover, this study also provides, for the first time, evidence that ASC-NT reduces the marketable production efficiency relative to ASC-GM but improves the environmental performance by increasing the potential energy that can be recycled within the cropping system across a wide range of European pedo-climatic conditions.

Temporal changes in biochemical indicators of soil quality in response to tillage, crop residue and green manure management in a rice-wheat system

Abstract Soil quality degradation in the last four decades is threatening the sustainability of puddled transplanted rice (Oryza sativa L.) – wheat (Triticum aestivum L.) (RW) system in north-western region of India. Hence comprehensive information on the influence of soil and crop management practices in intensive and nutrient exhausting RW system on soil quality is urgently needed. The present study evaluated the effects of crop residues, green manure and tillage on the changes in soil biochemical properties at different growth stages of wheat after five cycles of RW system. Four main plot treatments in rice included combinations of wheat straw and Sesbania green manure management: (1) PTRWS0, puddled transplanted rice (PTR) with no wheat straw (2) PTRWS25, puddled transplanted rice with 25% anchored wheat stubbles retained (3) PTRWS0 plus green manure (GM), and (4) PTRWS25 plus GM. Three sub-plots treatments in subsequent wheat included (1) CTWRS0, conventional tillage wheat without rice straw (2) ZTWRS0, zero tillage wheat without rice straw and (3) ZTWRS100, ZTW with 100% rice straw retained as surface mulch. The results showed that PTRWS25 plus GM and ZTWRS100 increased significantly all the soil biochemical properties (enzyme activities and glomalin related soil protein concentration) except phenol oxidase and peroxidase activities. The activities of dehydrogenase, β-glucosidase and concentration of easily extractable glomalin and total carbohydrate carbon under ZTWRS100 were 36.8, 24.6, 25.9 and 23.3% higher than CTWRS0. Application of GM and wheat straw retention in previous rice significantly increased grain yield of subsequent wheat crop by 26.5%. The majority of the increases in biochemical properties were higher at vegetative growth (at 40–45 days after sowing) and flowering (at 80–85 days after sowing) stages compared to the initial and at maturity. Principal component analysis identified β-glucosidase, cellulase and phenol oxidase activities as the most sensitive and reliable indicators for assessing soil quality for conservation agriculture based RW system.

Rice–wheat productivity and profitability with residue, tillage and green manure management

The rice–wheat system (RWS) practiced in northwestern parts of the Indo-Gangetic plains of India is highly productive, but conventional practices are resource (water, labour and energy) and cost intensive. A 4-year field study evaluated the effects of green manure (GM), crop residue and tillage on crop yields, economic profitability and soil fertility in a RWS. Four main plot treatments in rice included combinations of wheat stubble and Sesbania aculeata GM management: (1) puddled transplanted rice (PTR) with no wheat stubble, (2) PTR with 25% wheat stubbles (15–20 cm high) retained, (3) PTR with no wheat stubble plus GM, and (4) PTR with wheat stubble splus GM. Three sub-plots treatments in subsequent wheat included (1) conventional till wheat with rice straw removed (CTWR0), (2) zero till wheat with rice straw removed (ZTWR0) and (3) zero till wheat with 100% rice straw retained as surface mulch (ZTWR100). The results showed that main rice yield was significantly higher (8.0%) with 50% less fertilizer N application in GM compared with conventional PTR with no GM. Rice treatments did not affect the grain yield of subsequent wheat. ZTWR100 produced significantly higher mean wheat grain yield by 7.3% and 17.5% compared with CTWR0 and ZTWR0, respectively. System productivity was 11.5% higher in PTR with wheat stubble + GM followed by ZTWR100 compared with the conventional RWS and resulted in Rs 24,075 ha−1 more net returns. Significant increases in soil organic carbon, available P and available K contents were recorded in ZTWR100 over CTWR0. Recycling rice and wheat stubble in the field in RWS is also environment friendly as it avoids ill effects of straw burning.