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The current study was undertaken to investigate how organic and inorganic fertilizers shape soil bacterial communities and soil nitrogen and carbon status and to find their relationships with plant production. Soils were collected from fields under a three-year application of green manures (vetch (GMV), field bean (GMB), and wheat (GMW)), livestock manure (MF), inorganic mineral fertilizer (IF), and control (no nitrogen fertilization). The plants cultivated during the three years were tomato, watermelon, and pepper, respectively. The findings showed an increase in crop yields under both organic and inorganic fertilizers, in which the effects of leguminous green manures (GMV and GMB) were more pronounced, equal to +65–81% in tomato, +32–40% in watermelon, and +51–57% in pepper. An extensive modification in the bacterial communities was observed under organic fertilization. These changes were associated with a higher ratio of Proteobacteria (a copiotrophic phylum) to Acidobacteria (an oligotrophic phylum) in GMV and GMB, due to higher soil N content compared to IF and control treatments. Therefore, the data indicated an increase in soil N and organic C levels, as well as higher plant production by replacing IF with GMV, GMB, and MF, suggesting a promising movement to preserve the soil ecosystem. Such changes were more pronounced in MF-treated soils, where bacterial diversity improved and the heterogeneity of bacterial communities was preserved. [ABSTRACT FROM AUTHOR]

The green manure residual effect on soil health 2 years later in crop rotation is understudied. Little is known about weed biomass impact on soil microbial communities or their interactions. A Colchester County, NS, Canada, organic grain research trial during 2016-2017 comprised 2 or 3-year rotations with or without green manure crop prior to wheat, and then soybeans. Fall soil sampling was conducted both years. The soybean phase of the crop rotation was managed as weedy or non-weedy. Weedy soil showed significantly increased soil respiratory activity and fungal microbial biomass. Green manure treatments did not significantly influence soil health indicators. [ABSTRACT FROM AUTHOR]

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Background: Conventional monoculture or cereal-cereal sequence systems insist farmers to use excessive application of chemical fertilizer in agriculture resulting reduce the soil organic matter contents and structures. The inclusion of green manuring crops in a rotation is vital to improve the biochemical and physical properties of the soil via increasing the labile of organic matter and ultimately increased crops yield. Some complex molecules of green manuring crops takes a longer time of decomposition and thus nutrients reserve in soil and release latter which provide nutrients to the succeeding and following crops. So the current experiment aimed to study the residual effect of different in situ green manuring crops to the sub-sequent and following soil. Methods: The field experiment conducted during 2015 to 2016 with eight green manuring crops and rice and mustard was the subsequent and following crop. In situ incorporation of GM crops with 100% (F1) and 50% (F2) fertilizer, the prior and post-harvest soil (cropping pattern) of experiment field (0-15 cm) was collected and analyzed. Result: After two consecutive year, GM-T.aman-Mustard cropping pattern increased soil organic matter 0.04% to 0.07% and 0.02% to 0.03% (T1 and T2 with F1 and F2) and nitogen 0.05% (T1, T2 and T7 with F1 and F2) and K 0.2 to 0.5 meq/100 g (M. pudica with F1 and F2) and P 2 ppm to 15 ppm (T1, T2, T3 and T7 with F1 and F2) compared to initial soil. Rice yield with T1, T2, T3 and T6 shown higher with both fertilizer doses. Nitrogen fertilizer rates could be reduced after the incorporation of green manures in the succeeding and following crops. [ABSTRACT FROM AUTHOR]

The Colorado potato beetle (CPB) is an exceptionally challenging potato pest. Some regenerative farmers have reported that the use of transferred green manure mulch can considerably reduce CBP damage. Previous studies confirm this observation, but mainly with straw mulch, which is rarely used in Central Europe, and not embedded in the new regenerative cropping approach. For this, six trials conducted between 2014 and 2019 were evaluated, comparing CPB infestation in potatoes with and without transferred mulch as well as under a plough as a minimum till regime. In three out of six experiments, compost application was an additional factor. (I) Over all experiments, mulch significantly reduced initial infestation (−24%), egg masses (−27%) and larvae (−75%). Compost and reduced tillage added to these effects; (II) Mulch mainly resulted in delayed CPB infestation; (III) In a particularly warm season, when a second generation of CPB managed to emerge, regulatory effects of the mulch were not sufficient; (IV) Combination of transferred nutrient rich green manure mulch with reduced tillage, compost and other regenerative or agro-ecological techniques is recommended to achieve maximum regulation of CPB. [ABSTRACT FROM AUTHOR]

Green manure planting and rice straw returning are two effective ways of improving soil fertility of paddy fields in South China. The study on the effects of straw management practices on soil fertility during the winter fallow season is of great significance for providing a scientific basis for the rational utilization of straw and land resources in the rice cropping system of South China. Recently, the technique for co-incorporation of green manure planting and rice straw has been developed though little is known about the soil carbon pool and soil enzyme activity under co-application of the two organic materials in a mono-rice cropping system. This study is based on a three-year field experiment conducted during the winter fallow seasons from September 2010 to September 2013 in Jianghan Plain, Central China. The aim was to examine the effects of different treatments on soil organic carbon components, Carbon Pool Management Index (CPMI), soil enzyme activities and crop yield in a mono-rice cropping system were studied. The experiments included six treatments: 1) Rice Straw Mulching (RSM), 2) Rice Straw Burning(RSB) in situ, 3) Green Manure(GM) planting without rice straw return, 4) rice straw mulching with green manure planting (RSM+GM), and 5) a control (CK1) with no rice straw returning and 6) a control (CK0) with no rice straw returning and chemical fertilizer application. Soil samples (at depths of 0–20 cm) were taken and analyzed after rice was harvested in each of the years. The results showed that as compared with CK0 and CK1, RSB decreased the soil Stable Organic Carbon (SOC) content significantly (P<0.05) only in 2013. Conversely, the other treatments, RSM, GM and RSM+GM increased soil Active Organic Carbon(AOC) content, Carbon Pool Index(CPI), Activity (A), Activity Index (AI) and CPMI significantly (P<0.05). Additionally, the treatments of RSM and RSM+GM alsoincreased soil total organic carbon (TOC) content significantly (P<0.05). Most of these indices showed the largest increase in RSM+GM treatment, followed by RSM treatment, which was significantly higher than GM treatment. Compared with CK0and CK1, RSM, GM and RSM+GM treatments also increased soil catalase, urease and invertase activities. The RSM+GM treatment significantly (P<0.05) increased soil urease activity in 2011, 2012 and 2013, and improved soil catalase and invertase activity in 2012 and 2013, and proved to be superior to other treatments. Compared with CK1, the grain yields of rice in GM and RSM+GM treatments were significantly (P<0.05) increased by 6.88%-11.77% and 6.00%-13.40%, respectively, across the three years. However, no significant difference was observed among the grain yields by RSM, RSB and CK1 treatments. Pearson’s correlation analysis indicated that rice yield was significantly (P<0.01) positively correlated with TOC, AOC, CMPI and soil catalase, urease and invertase activities. These results indicated that the co-incorporation of green manure planting and rice straw in winter fallow season could improve soil fertility and increase crop yield, but the former was more conducive to the accumulation of soil organic carbon pool, while the latter was more conducive to the improvement of crop yield. For better soil quality, higher crop yield and the efficient utilization of crop straw, the co-incorporation of green manure planting and rice straw was recommended for the mono-rice cropping system in ecological condition similar to those in the location of this study.. [ABSTRACT FROM AUTHOR]

Dual‐use cover/green manure (CGM) crops and animal manure are used to supply nitrogen (N) and phosphorus (P) to organically grown field crops. A comprehensive review of previous research was conducted to identify how CGM crops and animal manure have been used to meet N and P needs of organic field crops, and to identify knowledge gaps to direct future research efforts. Results indicate that: (a) CGM crops are used to provide N to subsequent cash crops in rotations; (b) CGM‐supplied N generally can meet field crop needs in warm, humid regions but is insufficient for organic grain crops grown in cool and sub‐humid regions; (c) adoption of conservation tillage practices can create or exacerbate N deficiencies; (d) excess N and P can result where animal manures are accessible if application rates are not carefully managed; and (e) integrating animal grazing into organic field crop systems has potential benefits but is generally not practiced. Work is needed to better understand the mechanisms governing the release of N by CGM crops to subsequent cash crops, and the legacy effects of animal manure applications in cool and sub‐humid regions. The benefits and synergies that can occur by combining targeted animal grazing and CGMs on soil N, P, and other nutrients should be investigated. Improved communication and networking among researchers can aid efforts to solve soil fertility challenges faced by organic farmers when growing field crops in North America and elsewhere. [ABSTRACT FROM AUTHOR]

Agricultural productivity relies on a wide range of ecosystem services provided by the soil biota. Sustainable management practices, such as tillage and residue management, can influence structure and function of the soil microbiota, with direct consequences for the associated ecosystem services. Although there is increasing evidence that different tillage regimes alter the soil biological indices, we only have a limited understanding of their temporal changes in a rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system. We evaluated the effects of combinations of tillage, crop residue management and green manuring on soil biological indicators after 5 years of the practising rice–wheat system (RWS). Four main plot treatments in rice included the following: (a) PTRW0, puddled transplanted rice with no wheat straw retained; (b) PTRW25, puddled transplanted rice with 25% anchored wheat stubbles retained; (c) PTRW0 + Sesbania aculeate L. green manure (GM); and (d) PTRW25+GM, puddled transplanted rice with 25% anchored wheat stubbles retained+ GM. There were three subplot treatments in the subsequent wheat crop: (a) CTWR0, conventional tillage wheat with rice residue removed; (b) ZTWR0, zero tillage wheat with rice residue removed; and (c) ZTWR100, ZTW with 100% rice residue retained as mulch. The PTRW25+GM treatment, followed by ZTWR100, significantly increased soil microbial biomass carbon, basal soil respiration, microbial quotient and mineralization quotient measured during wheat‐growing season. These biological indicators were higher at vigorous vegetative wheat growth stage than at flowering stage and decreased at maturity. The principal component analysis of the assayed variables showed that all the variables significantly contributed to the variability in parameters examined and were more related to maximum tillering stage of wheat growth than to maturity or at sowing of wheat. Three highly effective biological indicators were microbial biomass carbon, microbial quotient and mineralization quotient, which responded significantly to changes in tillage and residue management practices in the RWS. We conclude that crop residues and green manure have significant to improve soil biochemical processes by improving soil organic carbon and soil biological indicators in rice–wheat cropping system. [ABSTRACT FROM AUTHOR]

Green manure crops play an important role in reducing chemical fertilizer applications while enhancing soil fertility. However, the effects of winter-planted green manure crops on rice paddy greenhouse gas (GHG) emissions are poorly understood. Based on a 35 years experiment, we analyzed the impacts of a rice-rice-green manure cropping system on rice yield and GHG emissions during both rice and winter-green manure seasons. Our experiment consisted of four treatments: ryegrass-rice-rice (Ry-R-R), milkvetch rice-rice (Mv-R-R), rapeseed-rice-rice (Rp-R-R) and fallow-rice-rice (Fa-R-R), arranged in a completely randomized design. Incorporation of winter-planted green manure had more impacts on yield and CH 4 emission in the early rice season than in the late rice season. Compared to the Fa-R-R, the Mv-R-R, Rp-R-R, and Ry-R-R systems increased annual yield by 15.4%, 11.8%, and 6.1%, respectively. However, Ry-R-R and Rp-R-R significantly increased annual CH 4 emissions by 116.73% and 52.45%, respectively, while Mv-R-R reduced CH 4 emissions by 16.3%, compared to Fa-R-R. The CH 4 emissions showed significant positive correlations with dissolved organic carbon, as well as the biomass and C/N ratio of the incorporated green manure plant materials. Although green manuring reduced N 2 O emissions in both winter and rice seasons, there was no significant difference in annual cumulative N 2 O emissions among the treatments. Ry-R-R and Rp-R-R increased annual yield-scaled GWP by 102.6% and 34.8%, respectively, while Mv-R-R was 27.8% lower, compared to the Fa-R-R. Our results suggest that Mv-R-R is the best choice of cropping system for yield sustainability and eco-friendly rice production over the long-term. • The impact of green manure crops on greenhouse gas emissions was studied. • Ry-R-R and Rp-R-R significantly increased CH 4 emissions by 116.73% and 52.45%, respectively. • Mv-R-R significantly increased rice yield by 15.4% and reduced CH 4 emission. • Mv-R-R is the most suitable cropping system for higher rice yield and lower CH 4 emission. [ABSTRACT FROM AUTHOR]

Crop rotation and green manure are the most ancient and popular cropping systems. This study sought to analyze the economic efficiency of sunflower where pea (Pisum sativum L.) either harvested or incorporated at the flowering stage in the soil before the sowing of sunflower in Europe and the final agricultural profit of such a cultivation system. Therefore, the main objective of this paper is to report the production costs and to find out which of the tested cultivation system gets sunflower cultivation economically viable in Greece and in Mediterranean region. To assess the economic efficiency, three-year field experiments were established in two contrasting environments in central Greece (Trikala and Larisa) and contained three different cultivation practices using legumes comprised the main-factor (T1: control, T2: legume incorporated at the flowering stage, T3: legume incorporated after seed harvest), while nitrogen fertilization comprised the sub-factor (N1:0, N2:50, N3:100 and N4:150 kgNha-1). The results derived from this study revealed the positive effect of the legume incorporation treatment (T2: legume incorporated at the flowering stage) where the final yield increased up to 5 t ha-1 regardless region. Moreover, depending on the year the T2 treatment increases the final yield 30-50% and a yield increase was also noticed to the treatment where the legume was harvested (T3: legume incorporated after seed harvest). Therefore the introduction of this scheme into future land use systems in Greece and more generally in Mediterranean basin should be seriously taken into consideration. [ABSTRACT FROM AUTHOR]

• Leguminous green manure increased SOC and TN stocks compared with summer fallow. • Coupling RothC and the correlation of SOC and TN can assess their future stocks. • Leguminous green manure will increase SOC and TN stocks by 107% and 158%. Estimating the dynamics and future sequestration potential of soil organic carbon stocks (SOCS) and total nitrogen stocks (TNS) is useful to determine whether cropping systems can promote sustainable production in terms of improving soil fertility. The Rothamsted Carbon (RothC) model and the correlations between SOCS and TNS were used to estimate the future SOCS and TNS of green manure-based wheat production systems on the Loess Plateau of China. The field study was a split-plot design with 4 main treatments (Huai bean, soybean and mung bean grown as green manure in summer, with a fallow treatment as the control) and 4 subtreatments (synthetic N rates of 0, 108, 135 and 162 kg ha−1 applied at wheat sowing). Leguminous green manure (LGM) treatments increased the amount of carbon and nitrogen returned to the field by 67–91% and 74–125%, respectively, compared with the fallow treatment (P < 0.05). These treatments also increased SOCS by 15–23% and TNS by 12–22% (P < 0.05) after 8 years in comparison with the fallow treatment. Coupling of the RothC model and the correlations between SOCS and TNS of the 3 LGM treatments generated acceptable simulations for the dynamics of SOCS and TNS. The projected SOCS for LGM and fallow treatments at the new equilibrium are 37.67–47.29 and 13.97–17.58 Mg ha−1, respectively. The corresponding TNS for LGM treatments are 5.42–6.79 Mg ha−1. The projection also indicates that under the LGM treatments, the SOCS and TNS at the new equilibrium will be 107% and 158% higher, respectively, than the values prior to the experiment. In conclusion, growing LGM to replace summer fallow would be a useful alternative to improve soil fertility and promote sustainable crop production. [ABSTRACT FROM AUTHOR]

Snowmelt runoff often comprises the majority of annual runoff in the Canadian Prairies and a significant proportion of total nutrient loss from agricultural land to surface water. Our objective was to determine the effect of agroecosystem management on snowmelt runoff and nutrient losses from a long‐term field experiment at Swift Current, SK. Runoff quantity, nutrient concentrations, and loads were estimated after a change in management from conventionally tilled wheat (Triticum aestivum L.)–fallow (Conv W‐F) to no‐till wheat–fallow and subsequently no‐till wheat–pulse (NT W‐F/LP) and to an organic system with a wheat–green manure rotation (Org W‐GM). The conversion from conventional tillage practices to no‐till increased snowmelt runoff likely due to snow trapping by standing stubble after summer fallow. Relatedly, runoff after no‐till summer fallow had higher dissolved P losses (0.07 kg P ha−1). Replacing summer fallow with a pulse crop in the no‐till rotation decreased snowmelt runoff losses and nutrient concentrations. The Org W‐GM treatment had the lowest P loss after stubble (0.02 kg P ha−1) but had high dissolved P concentrations in snowmelt following the green manure (0.55 mg P L−1), suggesting a contribution from incorporated crop residues. In this semiarid climate with little runoff, dissolved reactive P and NO3–N loads in snowmelt runoff were smaller than those reported elsewhere on the prairies (averaging <0.05 kg P ha−1 yr−1, and <0.2 kg NO3–N ha−1 yr−1); however, the nutrient concentrations we observed, in particular for P, even without P fertilizer addition for organic production, question the practicality of agricultural management systems in this region meeting water quality guidelines. Core Ideas: The conversion to no‐till farming caused an increase in snowmelt runoff.Greater snowmelt volumes can lead to increased nutrient losses.Pulse crops can decrease snowmelt runoff and nutrient concentrations compared with no‐till fallow.Green manure fallow can increase dissolved reactive P and NO3–N concentrations in snowmelt runoff.It may not be practical to meet the water quality guidelines for P concentrations in this region. [ABSTRACT FROM AUTHOR]

Abstract Chinese milk vetch (CMV) is widely used as a green manure due to its efficiency for nutrient preservation and soil fertility improvement, as well for providing more organic substances for soil organisms. Detritus micro-food web drives carbon and nutrient cycling and maintains ecosystem productivity. The effects of CMV amendment on detritus micro-food web were investigated in a six-year field experiment. Compared to the mineral fertilizers (NPK) alone, the fertilizers combined with CMV (NPK + CMV) increased soil organic carbon content, and thus enhanced the biomass of microorganisms, as well as protozoa abundance, while did not change micro-feeding nematode abundance (MN). This indicates a substrate-driven bottom-up effect. However, the green manure application increased omnivores-predators (OP) abundance and the OP/MN ratio, suggesting a top-down effect. Higher F/B ratio indicates a shift of the food web energy structure towards to fungi-dominated channel in the manured soil. Here, the green manure amendment should be encouraged to improve soil detritus micro-food web. Highlights • Green manure promoted micro-food web development by the bottom-up and top-down effects. • Green manure shifted micro-food web energy structure towards to fungi-dominated channel. [ABSTRACT FROM AUTHOR]

Highlights • Inter-row legumes contributed up to 90 kg fixed N ha−1 in coppiced tea tree crops at four sites. • Tea tree yield loss was observed with soybean intercrops at one site. • Further study needed to quantify potential N fertiliser savings when legumes are intercropped. Abstract Legumes play a key role in maintaining soil fertility in pasture systems and when used as a rotation crop or relay crop in annual cropping systems. Little is known about the potential to integrate green manure legumes into coppiced or ratooned perennial crop systems. We trialled the cultivation and green manuring of four annual legume species in the inter-row of coppiced tea tree (Melaleuca alternifolia) and assessed potential nitrogen (N) contributions using 15N natural abundance methodology. The yield and N uptake of tea tree crops with legumes was compared with tea tree crops amended with 5 t ha−1 (wet) poultry litter as per standard practice. At two field sites where warm-season legumes were sown in spring into coppiced tea tree stands, soybean (Glycine max) had a higher % N derived from the atmosphere (%Ndfa) than mung beans (Vigna radiata) (82 vs 68% at Casino and 65 vs 56% at Tweed Heads) and contributed more fixed N (shoots + roots) to the soil than mung bean at both sites (91 vs 24 kg fixed N ha−1 at Casino and 61 vs 33 kg fixed N ha−1 at Tweed Heads). Where cool-season legumes were sown into tea tree stands coppiced in winter, faba bean (Vicia faba) had a higher %Ndfa than chickpea (Cicer arietinum) at Rappville (88 vs 68%). Chickpea fixed less than 10 kg N ha−1 at Rappville, while faba been fixed 36 kg N ha−1 at Rappville and 92 kg N ha−1 at Leeville. At one site (Casino) tea tree yields in the legume plots were significantly (10–15%) lower than the poultry litter plots. The nutrient content of tea tree did not differ among treatments for any measured micro- or macronutrients, and the cause of the yield loss remains unknown. Ultimately, the highest fixed-N contributions of faba bean (92 kg fixed-N ha−1 at Leeville) and soybean (91 kg fixed-N ha−1 at Casino) equated to more than the amount of N in harvested shoot of a low yielding tea tree crop (67 kg N ha−1 at Leeville) and around 2/3 the N accumulated in harvested shoots of a high yielding tea tree crop (129 kg N ha−1 at Casino). Green manure legume crops have the potential to reduce the need for external N fertiliser inputs in coppiced tree crops, but further refinement is needed to integrate legumes into current weed control systems, optimise the timing of N release from decaying legume residues, and to minimise any competition between legumes and the tree crops for water, light or nutrients. [ABSTRACT FROM AUTHOR]

Purpose: Although green manure rotation is often used to promote soil fertility and crop yield, the effects of this management practice on the nitrogen or phosphorus balance and the relationship between nutrient balance and the increase in soil nutrients have not been systematically studied.Materials and methods: We investigated the apparent nitrogen and phosphorus balances and their associations with soil nitrogen and phosphorus increases, respectively, in a 34-year-old experimental site with various green manures and rice rotations using linear and logistic models. Cropping treatments included a rice-rice-winter fallow treatment as a control (RRW) and three green manure rotation treatments: rice-rice-ryegrass (RRR), rice-rice-oil rape (RRO), and rice-rice-Chinese milk vetch (RRC).Results and discussion: We found that apparent nitrogen and phosphorus balances of RRR, RRO, and RRC were 164, 162, and 149 kg hm−2, which were all significantly lower than 200 kg hm−2 of RRW (P < 0.05). Moreover, the optimal fitted model of the relationship between cumulative nutrient balance and the increase in soil nutrients was different among treatments. Specifically, the correlation coefficients of cumulative nitrogen balance and soil nitrogen increase of RRR, RRO, and RRC in the linear model (0.49, 0.80, and 0.63) were all significantly lower than in the logistic model (0.81, 0.90, and 0.82). The correlation coefficients of cumulative phosphorus balance and increase in soil phosphorus of RRW in the linear model (0.81) were significantly lower than in the logistic model (0.91). Parameter analysis of the optimal fitted model revealed that RRC would increase the storage capacity of soil nitrogen and decrease the rate of soil phosphorus accumulation.Conclusions: Our results suggested that long-term rice-rice-green manure rotation could significantly change the apparent nitrogen and phosphorus balance and their association with soil nitrogen and phosphorus content, respectively. Our study highlights the importance of green manure rotation in an agro-ecological environment and soil fertility in a double rice cropping system in red paddy soil. [ABSTRACT FROM AUTHOR]

We analyzed data from a long-term rice-wheat cropping sequence to evaluate the effects of integrated nutrient management (INM) on yield trends and sustainability, nutrient balance and soil fertility of the system. After 30th cycle, grain yield of both the crops significantly declined under control and highest rice and wheat grain yields were obtained when 50% N supplied through green manure and farm yard manure, respectively. The magnitude of yield slope under INM was found considerably higher than 100% recommended fertilizer (RDF). Sustainable yield index (SYI) for both the crops were found lower in control but considerably higher with the 100% RDF and under INM. The soils under all the treatments suffered an apparent loss of K and N (except where organics replacing 50% N). Correlation study also reveals K is the sole factor for the yield sustainability as apparent K balance was negatively correlated with SYI and yield slope. [ABSTRACT FROM AUTHOR]

In the worldwide search for new strategies in sustainable weed management, the use of allelopathic plants incorporated into the soil as green manure can help control weeds by releasing allelochemicals into the environment. In previous experiments, Eucalyptus globulus leaves incorporated into the soil as green manure were shown to have a notable potential for weed control. But, ‘what was exactly happening at chemical level?’ and ‘which were the compounds potentially responsible for the phytotoxic effects observed during those greenhouse assays?’ In the present study, in-vitro phytotoxicity bioassays and chemical analysis of eucalyptus leaves were carried out in order to explore the relationship between the temporal phytotoxic effects and the dynamics of chemical composition. For that, eucalyptus leaves were removed from soil at different sampling times during 30 days and analyzed for phenolic and volatile organic compounds (VOCs) by HPLC and HS-SPME/GC-MS, respectively. The phytotoxic potential of the aqueous extract and the volatile fraction was tested on the germination and early growth of Lactuca sativa. Eucalyptus leaves incorporated into the soil as green manure showed a continuous release of different phenolic and volatile compounds during a 30-day period of decomposition. Both fractions had phytotoxic effects during the time assayed; however, the target process of phytotoxicity was different: phenolic compounds being the factor causing germination inhibition and VOCs responsible for growth reduction. The dynamics of release of this cocktail of allelochemicals into the soil environment may be the responsible for the phytotoxicity observed in our previous works. [ABSTRACT FROM AUTHOR]

This study aimed at identifying the proper developmental stage for the cutting of cover crops with high nutrients content in the shoots of plants to be used as green manure on crop rotation in the no-tillage (NT) system. Crotalaria juncea, Cajanus cajan, Mucuna aterrima, and Sorghum bicolor were collected at five different vegetative stages for assessing of fresh weight yield (DWY) and dry weight yield (DWY), as well as determining the carbon (C)/nitrogen (N) ratio and the contents of nutrients in the shoots of plants. The experiment was performed on a completely randomized design, with five replicates. Except for the nutrients contents in S. bicolor, for the assessed legumes the DWY, FWY, C/N ratio, nutrient concentration and nutrient accumulation in the shoots have increased with the development of plants. Therefore, it can be inferred that grasses studied will provide greater soil cover, while the legumes will provide a greater nutrient cycling. [ABSTRACT FROM AUTHOR]

A challenge for dryland crop production in China is closing the yield gap while propelling the sustainable development of agriculture when the natural resources are limited. A 4-year fixed field experiment was conducted to analyse the effect of introducing leguminous green manure (LGM) to different cropping systems on soil water, residual nitrate, soil quality and economic benefits to compare their sustainability using a comprehensive scoring system. The main treatments of the experiment were different cropping systems, leguminous green manure-winter wheat (LGM-WW) and leguminous green manure-spring maize-winter wheat (LGM-SM-WW) with summer fallow-winter wheat (SF-WW) as control. LGM late incorporation, early mulch and early incorporation were sub-treatments for LGM-WW while stalk mulch, incorporation and move-away were the sub-treatments for LGM-SM-WW to study the effects of different LGM managements. Compared with SF-WW, LGM-WW decreased average soil water storage before wheat seeding by 11% and increased residual nitrate storage after wheat harvest by 77% while they were not significantly changed for LGM-SM-WW. The soil organic carbon (SOC) content of LGM-WW and LGM-SM-WW in the 0–20-cm layer significantly increased when using legume as mulch. The economic benefits of LGM-SM-WW were 2 times greater than those of the other 2 cropping systems. The scoring system indicates that the total score of LGM-WW ranged from 11.85 to 12.78, which was even lower than that of SF-WW (13.07). On the contrary, the total score of LGM-SM-WW ranged from 16.46 to 18.49. In conclusion, the scoring system determined that the optimum cropping system for sustainable dryland agriculture is leguminous green manure-spring maize-winter wheat with legume stalk mulch. [ABSTRACT FROM AUTHOR]

Increasing rice production to feed the world’s growing population while protecting the environment requires more optimal use of fertilizers. In China, the current high input, high output and high reliance on synthetic nitrogen (N) fertilizer in agriculture has resulted in high N losses, especially ammonia (NH 3 ) emission. Urea combined with green manure (GM) might be a promising approach to improve N fertilizer management. However, few studies have evaluated duckweed in this manner. Duckweed does not require arable land for cultivation and thus avoids competition with food crops. Therefore, a field experiment was conducted for three years with five treatments (CK, no N-fertilizer; CT, conventional practice, urea alone at 300 kg N ha −1 ; CTD, urea combined with duckweed at 300 kg N ha −1 ; RN, urea alone at 225 kg N ha −1 ; and RND, urea combined with duckweed at 225 kg N ha −1 ) in an intensive rice cropping system in the Taihu Region of China. The results for two years showed that urea combined with duckweed cover reduced NH 3 loss by 36–52% over CT. This reduction was attributed primarily to the formation of a physical barrier and the uptake of NH 4 + by duckweed. The 15 N recovery for 15 N balance conducted for one year was 38% higher and the 15 N loss was 16% lower for CTD than that of CT. Furthermore, urea combined with duckweed increased N accumulation in the aboveground plants by 14–25% over CT for the 3 years. As a result, urea combined with duckweed achieved higher rice yield by 9–10%, and higher net economic benefit by 10–11% over CT for the 3 years; however, using the conventional rate of 300 kg N ha −1 did not increase rice yield over using the reduced N rate of 225 kg N ha −1 , with or without duckweed. Thus, duckweed as GM combined with chemical fertilizer application provided an approach for increasing the rice yield without increasing inputs of N fertilizer and thereby provided a financially attractive option for farmers to achieve environmental integrity and ensure food security in rice production. [ABSTRACT FROM AUTHOR]

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A field experiment comparing different arable crop rotations was conducted in Denmark during 1997–2008 on three sites varying in climatic conditions and soil types, i.e. coarse sand (Jyndevand), loamy sand (Foulum), and sandy loam (Flakkebjerg). The crop rotations followed organic farm management, and from 2005 also conventional management was included for comparison. Three experimental factors were included in the experiment in a factorial design: 1) crop rotation (organic crop rotations varying in use of whole-year green manure (O1 and O2 with a whole-year green manure, and O4 without), and a conventional system without green manure (C4)), 2) catch crop (with and without), and 3) manure (with and without). The experiment consisted of three consecutive cycles using four-course rotations with all crops present every year, i.e. 1997–2000 (1st cycle), 2001–2004 (2nd cycle), and 2005–2008 (3rd cycle). In the 3rd cycle at all locations C4 was compared with two organic rotations, i.e. O2 and O4. The O2 rotation in the third cycle included spring barley, grass-clover, potato, and winter wheat, whereas C4 and O4 included spring barley, faba bean, potato, and winter wheat. For the O2 rotation with green manure there was a tendency for increased DM yield over time at all sites, whereas little response was seen in N yield. In the O4 rotation DM and N yields tended to increase at Foulum over time, but there was little change at Flakkebjerg. The DM yield gap between organic and conventional systems in the 3rd cycle varied between sites with 34–66% at Jyndevad, 21–44% at Foulum, and 32–52% at Flakkebjerg. The inclusion of grass-clover resulted in lower cumulated yield over the rotation than the treatment without grass-clover. The use of manure reduced the DM yield gap between conventional and organic systems on an average by 15 and 21%-points in systems with and without grass-clover, respectively, and the use of catch crops reduced the yield gap by 3 and 5%-points in the respective systems. Across all crops the agronomic efficiency of N in manure (yield benefit for each kg of mineral N applied) was greater in O4 compared with O2 for all crops. [ABSTRACT FROM AUTHOR]

Cover crops constitute one of the most promising agronomic practices towards a more sustainable agriculture. Their beneficial effects on main crops, soil and environment are many and various, while risks and disadvantages may also appear. Several legumes show a high potential but further research is required in order to suggest the optimal legume cover crops for each case in terms of their productivity and ability to suppress weeds. The additional cost associated with cover crops should also be addressed and in this context the use of grain legumes such as cowpea, faba bean and pea could be of high interest. Some of the aspects of these grain legumes as far as their use as cover crops, their genetic diversity and their breeding using conventional and molecular approaches are discussed in the present review. The specific species seem to have a high potential for use as cover crops, especially if their noticeable genetic diversity is exploited and their breeding focuses on several desirable traits. [ABSTRACT FROM AUTHOR]

Short-cycle crops use part of the N from green manure fertilization, while the remainder continues to be available for the subsequent ones. The aim of the present work was to evaluate the N use efficiency of sunn hemp, Crotalaria juncea L. (Fabaceae) in the sequential cropping of Brassica oleracea var. italica (Brassicaceae) followed by zucchini, Cucurbita pepo L. (Cucurbitaceae). Three doses of C. juncea green manure 3, 6, and 9 t ha −1 were evaluated, each one added with 12 t ha −1 of organic compost. The N use efficiency was based on the 15 N isotope dilution technique. The total N accumulated in the shoots of broccoli and zucchini with the highest dose of C. juncea was 78.25 and 70.42 kg ha −1 , respectively. The green manure-N recovery efficiency and quantity with the highest doses of C. juncea in broccoli were 74.39 and 47.42 kg ha −1 and in zucchini 58.82 and 31.95 kg ha −1 , respectively. The green manure-N supplied 28.50% of N for broccoli and 16.22% for zucchini. The N residual effect from C. juncea green manure is enough to provide for the cultivation of at least two vegetable crops — broccoli followed by zucchini. [ABSTRACT FROM AUTHOR]

Developing and implementing improved management practices are necessary to enhance the sustainability of organic cropping systems. This study examined the effects of various organic cropping systems on soil greenhouse gas (GHG) emissions and crop yields in Québec, Canada. Organic cropping systems combining different: (i) crop sequences (barley [ Hordeum vulgare L.]-grain corn [ Zea mays L.], soybean [ Glycine max (L.) Merr.]-spring wheat [ Triticum aestivum L.], and grain corn-soybean), (ii) nitrogen (N) sources (poultry manure [PM] and/or a fall-seeded green manure [GM] or no applied N), and (iii) primary tillage intensities (moldboard plough [MP] or chisel plough [CP]) were compared to a perennial forage (PF) and a bare fallow (BF) control. During the 2019 and 2020 snow-free seasons, nitrous oxide (N 2 O) and methane (CH 4) emissions, soil water content, soil temperature, and mineral N concentrations were monitored periodically on a sandy loam soil. The lowest cumulative N 2 O emissions were found in CP-GM (0.52 ± 0.11 kg N ha-1 in 2019 and 0.47 ± 0.06 kg N ha-1 in 2020), whereas the highest N 2 O emissions were found in MP-PM in 2019 (3.55 ± 0.72 kg N ha-1) and BF in 2020 (1.44 ± 0.20 kg N ha-1). For the barley-grain corn sequence, the CP-GM treatment generated N 2 O emissions that were 40–70 % lower and yields that were 33–51 % lower than the MP-PMGM and CP-PMGM systems, which showed equivalent N 2 O emissions and yields. Yield-scaled N 2 O emissions were equivalent for all cropping systems. Peak N 2 O daily fluxes in the PF occurred shortly after cutting in 2020. During both years, CH 4 emissions varied from − 0.65 to + 0.18 kg C ha-1 with no detectable differences among cropping systems. The CP-GM cropping system minimized area-scaled N 2 O emissions without increasing yield-scaled emissions. However, this was a two-year study on a site that was recently converted from conventional agriculture, so a long-term assessment is still necessary to determine whether the benefits associated with these cropping systems change over time. • Soil N 2 O and CH 4 emissions were compared for different organic cropping systems. • Combining reduced tillage and green manures minimized area-scaled N 2 O emissions. • Green manure and poultry manure generated similar yield-scaled N 2 O emissions. • Legume-based perennial forage crop and grain crops generated similar N 2 O emissions. • Dry conditions during spring resulted in lower N 2 O emissions despite high NO 3 content. [ABSTRACT FROM AUTHOR]

Monocropped rice system is an important intensive cropping system for food security in China. Green manure (GM) as an alternative to fertilizer N (FN) is useful for improving soil quality. However, few studies have examined the effect of Chinese milk vetch (CMV) as GM on nitrous oxide (N2O) emission from monocropped rice field in south China. Therefore, a pot-culture experiment with four treatments (control, no FN and CMV; CMV as GM alone, M; fertilizer N alone, FN; integrating fertilizer N with CMV, NM) was performed to investigate the effect of incorporating CMV as GM on N2O emission using a closed chamber-gas chromatography (GC) technique during the rice growing periods. Under the same N rate, incorporating CMV as GM (the treatments of M and NM) mitigated N2O emission during the growing periods of rice plant, reduced the NO3- content and activities of nitrate and nitrite reductase as well as the population of nitrifying bacteria in top soil at maturity stage of rice plant versus FN pots. The global warming potential (GWP) and greenhouse gas intensity (GHGI) of N2O from monocropped rice field was ranked as M

Green manure can be a source of nutrients for crops to spare some of the mineral fertilizer required for sustainable intensification of agriculture in smallholder context. We explored with a calibrated model the potential of legume green manure to help spare mineral fertilizer for sustainable intensification of rainfed rice production in Madagascar highlands. This study builds on a two-year rice experiment with rice and green manure as previous crop. The experiment investigated the response of rainfed rice growth to the incorporation into the soil of i) rice residue only (C:N ratio of 44.9) and ii) mucuna + crotalaria green manures (C:N ratio of 18.7). Two levels of fertilizer were investigated: manure only (5 t DM ha−1) (F1) and manure (5 t DM ha−1) in combination with mineral fertilizer (136 kg N ha−1) (F2). The crop model STICS was calibrated against observed soil water and soil mineral N, plant N uptake, aboveground biomass and grain yield to reproduce the impact of residue type and fertilizer input on mineralization of organic N in soil and in crop residue, crop growth and grain yield. The calibrated crop model was then used to explore rice response to mineral N fertilizer, with or without green manure, for the historical climate (1994–2018). Relative Root Mean Square Error (rRMSE) of model simulations fell within the observed relative variation in grain yield due to treatment effect. With green manure, mineral N available for rice increased compared with the situation without green manure, leading to greater agronomic use efficiency of N fertilizer. Green manure helped spare mineral fertilizer to achieve a reference yield set at 75 % of potential yield. This reference yield (3.67 t ha−1 on average across years) was reached with 40 kg N ha−1 with 6 t ha−1 of green manure, and 100 kg N ha−1 without green manure. The analysis of rice yield inter-annual variability indicated that (i) N leaching increased with total seasonal rainfall, which undermined the benefits of green manure on rice productivity in wetter years, and (ii) the increase in rice productivity allowed by the green manure did not fully compensate the rice yield foregone with the cultivation of the green manure. The calibrated model can be a useful tool to explore additional management strategies that will help maximize the benefit of green manure for sustainable intensification of rice-based cropping systems, especially in low-input cropping systems. • Impacts of green manure incorporation into the soil was assessed using modeling approach. • Rice response to mineral N fertilizer and green manure was evaluated with historical climate. • N available for crop increased with the use of green manure. • Green manure helped spare mineral fertilizer to achieve potential yield. • Benefits of green manure is undermined in wet years partly due to N leaching. [ABSTRACT FROM AUTHOR]

Rice–rice rotation is the most important intensive cropping system for food security in China. So far, few studies have examined sustainability of double-rice cropping system using partial substitution of fertilizer N (FN) by green manure (GM). The effects of 100% FN (N 100 ) and different substitution rates of FN by GM (80%, 60%, 40% and 20% FN plus 20%, 40%, 60% and 80% N through GM, and represented respectively by N 80 M 20 , N 60 M 40 , N 40 M 60 and N 20 M 80 ) on the rice productivity and N-supplying capacity of paddy soil were evaluated in double-rice system from 2008 to 2013. Soil organic matter and total N content in the 0–15 cm layer and rice grain yield of early and late rice annually increased in N 80 M 20 and N 60 M 40 plots, but decreased in N 100 , N 40 M 60 and N 20 M 80 plots. Compared with N 100 plots, the NH 4 + -N content and agronomic efficiency of applied N significantly increased in N 80 M 20 and N 60 M 40 plots. The grain yield and sustainable yield index of rice crops were improved in N 80 M 20 and N 60 M 40 plots, while declined in N 40 M 60 and N 20 M 80 . Soil NO 3 − -N content decreased significantly under partial substitutions of GM for FN. It can be concluded that the appropriate substitution of GM for FN (e.g., 20–40%) is beneficial for improving the productivity and sustainability of paddy field under double-rice cropping system. [ABSTRACT FROM AUTHOR]

Excessive application of N fertilizer in pursuit of higher yields is common due to poor soil fertility and low crop productivity. However, this practice causes serious soil depletion and N loss in the traditional wheat cropping system in the Loess Plateau of China. Growing summer legumes as the green manure (GM) crop is a viable solution because of its unique ability to fix atmospheric N 2 . Actually, little is known about the contribution of GM N to grain and N utilization in the subsequent crop. Therefore, we conducted a four-year field experiment with four winter wheat-based rotations (summer fallow-wheat, Huai bean–wheat, soybean–wheat, and mung bean–wheat) and four nitrogen fertilizer rates applied to wheat (0, 108, 135, and 162 kg N/ha) to investigate the fate of GM nitrogen via decomposition, utilization by wheat, and contribution to grain production and nitrogen economy through GM legumes. Here we showed that GM legumes accumulated 53–76 kg N/ha per year. After decomposing for approximately one year, more than 32 kg N/ha was released from GM legumes. The amount of nitrogen released via GM decomposition that was subsequently utilized by wheat was 7–27 kg N/ha. Incorporation of GM legumes effectively replaced 13–48% (average 31%) of the applied mineral nitrogen fertilizer. Additionally, the GM approach during the fallow period reduced the risk of nitrate-N leaching to depths of 0–100 cm and 100–200 cm by 4.8 and 19.6 kg N/ha, respectively. The soil nitrogen pool was effectively improved by incorporation of GM legumes at the times of wheat sowing. Cultivation of leguminous GM during summer is a better option than bare fallow to maintain the soil nitrogen pool, and decrease the rates required for N fertilization not only in the Loess Plateau of China but also in other similar dryland regions worldwide. [ABSTRACT FROM AUTHOR]

[Objective] The aim was to clear the suitable green manure cropping pat-terns in Xiangxi tobacco-planting areas. [Method] 8 treatments were set to study the effects of the monoculture and mixed cropping of common vetch (Vicia gigantea Bge.), perennial ryegrass (Lolium) and rapeseed (Brassica campestris L.) on physical and chemical properties of soil and economic characters of flue-cured tobacco. [Result] (1) Green manure turnover can reduce soil bulk density by 1.08%-8.62%, and the effect of green manure mixed cropping pattern was the best. (2) Green manure turnover also can increase the soil nutrient, soil organic matter, total nitrogen (N), total phosphorus (P), total potassium (K), alkali-hydrolyzale N, rapidly available P and rapidly available K by 1.44%-6.10%, 0.01-0.12 g/kg, 1.89% - 11.32%, 0.12%-3.56%, 1.06%-11.76%, 0.04%-18.93% and 0.98%-23.12%, respectively, and the effect of the monoculture of common vetch was the best. (3) The overall change of soil pH was not obvious. (4)Green manure turnover can increase the yield and output of flue-cured tobacco, and the effect of the monoculture of common vetch was the best. [Conclusion] The monoculture of common vetch can be generalized in the dry land of Xiangxi tobacco-planting areas. [ABSTRACT FROM AUTHOR]

Soilborne potato diseases are persistent problems in potato production. Use of disease-suppressive rotation crops, such as Brassica spp. (mustards, rapeseed) and sudangrass, has shown potential for management of soilborne diseases and enhanced yield in various crop production systems. However, how to best implement these crops into productive potato cropping systems has not yet been determined. In this research, potential disease-suppressive crops were evaluated under four different types of production management (as a cover crop, green manure, harvested crop-residue incorporated, and harvested crop-residue not incorporated) in potato rotation field trials, and their effects on disease, yield, and economic viability determined. Mustard blend, sudangrass, and rapeseed rotations reduced the tuber disease black scurf (by 16-27 %) and increased yield (by 6-11 %) relative to a barley rotation control, but only mustard blend consistently reduced common scab (by 11 %). All rotation crops managed as green manures produced lower disease (by 15-26 %) and higher yields (by 6-13 %) than other management practices. Overall, the combination of mustard blend managed as a green manure was most effective, reducing scurf by 54 % and increasing yield by 25 % relative to a soybean cover crop. The use of mustard or rapeseed as a harvested crop with incorporation provided the best economic return, increasing net income by more than $860/ha relative to the standard barley rotation, but mustard blend grown as a green manure or non-incorporated harvest crop also substantially increased net income ($600 to $780/ha). [ABSTRACT FROM AUTHOR]

Crop rotation has been used for the management of soilborne diseases for centuries, but has not often been planned based on scientific knowledge. Our objective was to generate information on Sclerotium rolfsii dynamics under different crop or intercrop activities, and design and test a research approach where simple experiments and the use of models are combined to explore crop sequences that minimize Southern blight incidence. The effect of seventeen green manure (GM) amendments on sclerotia dynamics was analyzed in greenhouse and field plot experiments during two years. The relative densities of viable sclerotia 90 days after winter GM (WGM) incorporation were generally lower than after summer GM (SGM) incorporation, with average recovery values of 60% and 61% for WGM in the field, 66% and 43% for WGM in the greenhouse, and 162% to 91% for SGM in the greenhouse, in 2009 and 2010, respectively. Sclerotia survival on day d after GM amendment was described by the model S f = S i ×exp(−b × d), relating initial (S i ) and final (S f ) sclerotia densities. Relative decay rates of the sclerotia (b) in SGM amended soil were largest for alfalfa (0.0077±0.0031day−1) and sudangrass (0.0072±0.0030day−1). In WGM amended soil, the largest b values were for oat (0.0096±0.0024day−1), wheat (0.0090±0.0024day−1) and alfalfa (0.0087±0.0023day−1). The effect of three cropping sequences (sweet pepper–fallow, sweet pepper–black oat and sweet pepper–onion) on sclerotia dynamics was analyzed in microplot experiments, and the data were used to calibrate the model P f = P i /(α + βP i ), relating initial (P i ) and final (P f ) sclerotia densities. Median values for the relative rate of population increase at low P i (1/α, dimension less) and the asymptote (1/β, number of viable sclerotia in 100g of dry soil) were 8.22 and 4.17 for black oat (BO), 1.13 and 8.64 for onion (O), and 6.26 and 17.93 for sweet pepper (SwP). By concatenating the two models, sclerotia population dynamics under several crop sequences were simulated. At steady state, the sequence SwP–O–Fallow–BO resulted in the lowest long-term sclerotia density (7.09sclerotia/100g soil), and SwP–Fallow in the highest (17.89sclerotia/100g soil). The developed methodology facilitates the selection of a limited number of rotation options to be tested in farmers’ fields. [ABSTRACT FROM AUTHOR]

Abstract: Vegetable production makes an intensive use of pesticides, and a major challenge is to build alternative cropping systems that can control pests and diseases with fewer uses of chemical products. An on-farm analysis was conducted in Southeast France to assess the efficacy of several cropping systems in simultaneously controlling two major pests: root-knot nematodes (Meloidogyne spp.) and lettuce drop due to Sclerotinia sclerotiorum. Ten cropping systems resulting from the combinations of three crop sequences and two alternative techniques, solarization and green manure, were assessed during two years. The use of solarization once a year or once every two years limited the occurrence of S. sclerotiorum. Sorghum green manure tended to increase S. sclerotiorum incidence; the effect was positively correlated with green manure duration. Especially when no vegetable was cropped in summer, the green manure crop duration was lengthened and this probably created soil conditions favorable to the development of the fungus. The incidence of root-knot nematodes was largely dependent on crop rotation: a melon crop in summer increased its incidence on the subsequent lettuce crops whereas a summer sorghum cover crop had no effect. The cropping systems that limited Sclerotinia development in soil tended to support the root-knot nematode populations. These results should motivate farmers and advisers to adopt a systemic analysis and take into account the various interactions among inoculum level, soil characteristics, crop rotations, and technical management options for designing sustainable vegetable production systems. [Copyright &y& Elsevier]

Field experiments were conducted during the summer-rainy (June–November) and winter (November–April) seasons of 2009–2010 and 2010–2011 at the research farm of the Indian Agricultural Research Institute, New Delhi, India. The objectives were to determine the residual effects of zinc (Zn) fertilizer sources [Ethylene diamine tetra acetic acid (EDTA)-chelated Zn (12% Zn), ZnSO4·7H2O (21% Zn), ZnSO4·H2O (33% Zn), ZnO (82% Zn) and ZnSO4·7H2O+ZnO (50%+50%)] and summer green manure crops [Sesbania aculeata(dhaincha),Crotalaria juncea(sunhemp) andVigna unguiculata(cowpea)] on yield, Zn concentration and quality of durum wheat (Triticum durumDesf.) under a Basmati rice–durum wheat cropping sequence. Basmati rice was harvested at maturity and durum wheat (variety PDW 291) was grown to evaluate residual effects of Zn fertilizer sources and summer green manure crops. Beneficial residual effects of Zn fertilizer sources and summer green manures on durum wheat response were observed, with significant increases in all of the determined parameters, in comparison with the control (no Zn application or summer fallow in preceding Basmati rice). The rates of increase varied among Zn sources and summer green manures. Residual effect ofS. aculeataincorporation led to a significant increase in grain and straw yields, Zn concentration and quality parameters of durum wheat. Among the Zn fertilizer sources, residual effect of EDTA-chelated Zn was found to be the greatest with respect to grain and straw yields, Zn concentration and quality parameters. Highest Zn concentration in durum wheat grain and straw was recorded with residual effect of EDTA-chelated Zn, followed by ZnSO4·7H2O, ZnSO4·H2O, ZnSO4·7H2O+ZnO, ZnO and control.S. aculeataincorporation and EDTA-chelated Zn treatments were found to be the best combination with respect to residual effects for higher quality durum wheat production. [ABSTRACT FROM AUTHOR]

Net nitrogen (N) balance after rice (Oryza sativaL.) and its relationship with yield and N uptake of succeeding wheat crop was studied in a greenhouse. Three urea-enriched green manures, namely dhaincha (Sesbania aculeataL.), cowpea (Vigna unguiculataL.), and guar (Cyamopsis tetragonolobaL.) were compared with split application of urea in a rice–wheat cropping sequence. After rice, a negative N balance was measured in all treatments; however, the N balance values were greater with urea than with green manures. The N balance was positively correlated with the N content but negatively correlated with lignin content and carbon (C)–N ratio of the green manures. Lignin content was a better index than C/N ratio for predicting the net N balance, which described 82.3% of the total variations. Efficiency of residual N utilization by wheat could be determined by estimating the N balance after rice. Net N balance after rice can be used as a yardstick for the prediction of yield and N uptake by wheat crop. [ABSTRACT FROM AUTHOR]

Abstract: In a field experiment, we evaluated effects of three different organic white cabbage-cropping systems (O1, O2, O3) on the cabbage root fly, Delia radicum, and its egg predators and pupal parasitoids over 3 years. The three systems all complied with regulations for organic production, but varied in external nutrient input and N-recycling, and were compared to a conventionally farmed control. One organic system (O3) included an intercropped strip of green manure between crop rows. Oviposition by D. radicum was generally not reduced in organic cropping systems. However, higher pupae/egg ratios were observed in the conventional compared to all organic systems, indicating that immature survival from oviposition to pupation was reduced under all the three organic farming practices. In organic system O2 most small coleopteran predators were recorded, but predation on fly eggs was not significantly higher in organic treatments. Pupal parasitization rates ranged from 26.5% to 59.5%, but no significant differences among farming systems were found. Although reduced D. radicum survival could not be attributed solely to natural enemies, the results indicated that organic farming practices in general contribute to the suppression of belowground pests in cabbage production. [Copyright &y& Elsevier]

A vetiver grass and bean cropping system could be used for improving physical properties of deteriorated soils. The objective of this research was to study effects of vetiver grass (Vetiveria zizanioidesNash) and green manure management on properties of Map Bon, a coarse-loamy variant of sandy loam, with low organic matter and medium erosion, at the Khao Hin Son Research Station, Chachoengsao, Thailand, from March 2001 to April 2003. The experiment was carried out in a split-plot design in a randomized complete block design with three replications. There were two main plots (with and without vetiver grass) and four subplots (without bean and with eitherVigna sinensis, Canavalia ensiformis,orDolichos lablab). This work showed that the treatments with vetiver grass could increase organic matter and saturated hydraulic conductivity; however, bulk density and soil hardness decreased and total porosity and available water-holding capacity were not affected. The use of green manure affected soil hardness and saturated hydraulic conductivity. The treatments with vetiver grass and green manure could increase available water-holding capacity of the soil also. [ABSTRACT FROM AUTHOR]

Copyright of Agricultural Sciences / Zemès ukio Mokslai is the property of Lithuanian Academy of Sciences Publishers and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Fields and Homegardens (representative of tropical smallholder extensive and intensive systems) were compared for soil quality and productivity of maize and mungbean in a hilly region of Sri Lanka (twinned 30 farms with Fields and Homegardens, each) over 2 years. The inclination categories were Flat (0–10%), Moderate (10–30%) and Steep (>30%). On half of the farms, green manure was added using Gliricidia leaves (3tonnesha−1 per season). Soil organic matter contents of Homegardens were at least 30% greater than in Fields, most pronounced in the Flat category. After 2 years of continuous maize and mungbean cropping in the major and minor rainy seasons, respectively, SOM generally declined; the greater depletion rate in Homegardens was positively correlated with crop yields. With recommended fertilizers (NPK), maize yield was always significantly higher in Homegardens than in Fields Flat and Moderate, this hold true at Steep lands only without NPK. Maize yield with NPK was on average two times higher than with Gliricidia alone, a respectable 4.5tonnesha−1 at Flat and Moderate, and 3.5tonnesha−1 even on Steep lands, seemingly the chemical soil fertility was more lacking than the physical properties. Gliricidia alone had no impact on yield in Fields but just in Homegardens, yield was increased by almost 30% in comparison to Zero fertilizer, an indication that chemical fertility was not directly supported by Gliricidia. Mungbean yields were generally less influenced by treatments, just the beneficial short term impacts of Gliricidia in Fields were relatively much higher than in maize. Conclusively, the long term input of organic manure in Homegardens was translated into a higher productivity in comparison to extensively managed Fields. However, the annual green manure supply supported yields mostly at marginal input levels and was overridden by mineral fertilizers independent of the inclination. Although, the usefulness of Gliricidia in degraded Steep lands was proven, the great risk of erosion remains in this landscape. Arable cropping there should be replaced by access to NPK on low inclined land once socio-economic conditions allow it. [Copyright &y& Elsevier]

The aim of this work was to evaluate the transfer of N via biological nitrogen fixation from green manures to intercropped lettuce using the 15N abundance method. The treatments consisted of lettuce with black oats, lettuce with cowpea, lettuce with white lupin and monocropped lettuce (control). Green manures were sown at two different times including the following: 60 days before transplanting of lettuce seedlings and simultaneous to transplanting of lettuce seedlings. N transfer was estimated using the natural 15N abundance method. It was observed that lettuce intercropped with green manures reached the same fresh mass of monocropped lettuce when the green manures were sown at the same time as the vegetables were planted. However, when the green manures were sown previously, the fresh mass of the monocropped lettuce was higher, and independent of the sowing time of green manures, the monocropped lettuce reached a higher dry mass. White lupin and cowpea transferred higher amounts of N regardless of sowing time, and the C:N ratio of white lupin to cowpea was lower compared to black oats. Intercropping with white lupin, cowpea and black oat transferred 18, 17 and 7% of N, respectively, to lettuce. [ABSTRACT FROM AUTHOR]

The autumn vetchs are fodder plants with multiple uses. They can be used as main, stubble or intermediate crops or can be successfully used as green manure on different soil types. The autumn vetch inclusion in the agricultural crop rotation is auspicious attributes as it can contribute to the improving of the soil properties (density, porosity, accumulation of humus in soil) primarily because legumes are able to fix the nitrogen atmosphere (CLARK et al, 2007; SCHULZ ET AL, 1999). The purpose of this paper is to determine correlations between the main morphological characters of autumn vetches in the phenophase 46 (according to the code BBCH- U WE M EYER, 2001) in order to evaluate their potential, when they are used as green manure. Thus there was shown a strong linear correlation between the internodes number and the number of roots, between the plant weight and the shrub height, between the root number and the nodule number, between the plant weight and the number of roots, respectively between the plant weight and the nodule number. Based on these correlations it was determined functional dependences between these well correlated morphological characters. In particular, it was determined the linear regression of the root number based on the internodes number, the linear regression of shrub height depending on the plant weight, and the linear regression of nodule number based on the number of roots. As biological material was used the autumn vetch, seeded in September, after a bearded ryegrass culture. The vetch will be incorporated into the soil, as green manure. In this situation, we are interested in both the morphological characters at the ground surface, as they represent the amount of biomass and the root characters because they influence the soil processes, and by their death they enrich the humus layer. It is not insignificant that the morphological characters development at the ground surface increases the characters and properties of root such as root weight, main root length, number of secondary roots and the root nodule number. There are positive linear correlations between the number of roots and the internodes number; the shrub height and the plant weight; the nodule number and the number of roots Based on these correlations there were determined functional dependencies between these well correlated morphological characters. [ABSTRACT FROM AUTHOR]

Adoption of legumes in cereal-based cropping systems and improvement of organic fertilizers are important to reduce chemical fertilizer use. We supplied compost and green manure (GM) of green pea plant residue (GP), without supplementation or supplemented with dried chicken manure (CM) and/or rapeseed oil residue (RR), for wheat and examined the effects of compost and GM (remaining fertilizer) on the rice of pea-wheat-rice system in two factorial pot experiments. Additions of pea residue resulted in an increase of 30% grains of rice compared to without addition, and compost increased 25% grains against GM. Supplementation increased 63-70% of rice grains as compared to the control. Nitrogen (N) and potassium (K) recovery efficiencies were correlated with yield, which suggested that composting and supplementation enabled effective nutrients accumulation in plant, resulting in better yield. Therefore, it is recommended that composting of GP with CM plus RR improves effectiveness of pea on rice of a pea-wheat-rice system. [ABSTRACT FROM AUTHOR]

Green manures are important in tropical cropping systems and are planted in degraded soils, thus affecting early growth. Pot and field experiments evaluated the impact of soil fertility on early growth of two important tropical green manures (Crotalaria juncea and Tithonia diversifolia) when compared to that of maize (Zea mays) with high and low levels of phosphorus fertilizer. Growth of tithonia was not affected by soil fertility level irrespective of phosphorus fertilizer, indicating its suitability for degraded soils. Crotalaria was affected by soil fertility (root growth was stimulated by phosphorus), indicating its potential for soils with some degree of fertility. Maize was significantly affected by soil fertility and phosphorus fertilizers, indicating the requirement of fertile soils for the successful development of a good root and shoot system. The importance of field studies in the tropics is also presented as the diverse field conditions reduces significant effects found in pot studies. [ABSTRACT FROM AUTHOR]

Abstract: We measured methane emissions from double-crop rice fields with long-term fertilizing systems in Taoyuan county in Hunan province, China. These long-term experiments have been ongoing since 1990, with six different fertilizing systems including balanced mineral fertilizers or combined organic/mineral fertilizers as following: nutrient K deficit (NP), nutrient P deficit (NK), balanced mineral nutrients (NPK), combined organic/mineral fertilizers at full rate (FOM) or at reduced rate (ROM) and no-fertilizer as a control (CK). Results showed that the average CH4 fluxes ranged between 11.8 and 19.4mgm−2 h−1 for the early rice season and between 23.3 and 43.8mgm−2 h−1 for the late rice season. Out of the total emissions, 66–71% from the double-cropping system occurred during the late rice season. Cumulative emissions of CH4 from two rice crops ranged from 65.9 to 121gm−2, ranking as following: FOM>ROM>NPK>NK>NP>CK. Results indicated that high CH4 emission rates from rice fields in Hunan province were dominated comprehensively by rice straw incorporation and extended flooded periods. Therefore, it is recommendable to drain the flooded field intermittently for double rice cropping systems. In particular, rice straw should not be incorporated into soil before transplanting while milk vetch as green manure could be encouraged with regards to crop productivity and greenhouse gas mitigations. [Copyright &y& Elsevier]

Abstract: The present study investigated the effect of cultivation with or without inorganic fertilization, and farmyard manure (FYM), paddy straw (PS), and green manure (GM) along with inorganic fertilizers on soil aggregation, array and accessibility of aggregate associated C, specially the micro-scale location or stability of soil organic C (SOC) at 0–0.15, 0.15–0.30 and 0.30–0.45m depths on a silty clay soil of Inceptisol in the hot, humid subtropics of eastern India, with a long-term 21year old rice (Oryza sativa L.)–wheat (Triticum aestivum L.) cropping system. In general, structural indices were found higher in the soil receiving organic amendments (NPK+FYM, NPK+PS and NPK+GM) than the minerally fertilized (NPK) soil or the control and in the surface than in depth. Among treatments including organic amendments, GM seems to be less efficient in increasing aggregate stability. The aggregated C decreased with increasing soil depth and was distributed as ‘silt+clay’ C (<0.05mm)>coarse macroaggregated C (CMacAC, >2.0mm)=mesoaggregated C (MesAC, 0.25–2.0mm)>coarse microaggregated C (CMicAC, 0.05–0.25mm). Within a size class, aggregated C concentrations of the organically amended treatments were in the order of FYM≥PS≥GM, limiting the negative effect of ploughing but not to the level of native soil. A significant positive linear relationship was found between the ‘silt+clay’ C and the silt and clay content of this soil. Out of the added organics, C from FYM was stabilized more than PS and GM, respectively, and C from GM was stabilized more in ‘silt+clay’ sized fraction than FYM and PS. This study represents a further step towards understanding the bio-chemical nature of organics and their array with mineral particles for C stabilization. [Copyright &y& Elsevier]

This study evaluated the impact of conventional practices (fertilizer alone) and diverse farming approaches (such as green manuring, farmyard manure application, rice-residue incorporation, residue mulching, residue removal and residue burning) on soil attributes. A total of thirty-five farm sites were selected, with five sites (replications) for each farming approach system, which were used over the past three years in the study farms. Characterization of rice residues of all cultivars, green manure crop (sesbenia: Sesbania sesban) and decomposed farmyard manure samples showed differential behaviours for macronutrients and micronutrients. Continuous application of inorganic fertilizers significantly influenced soil attributes, especially electrical conductivity, nutrient contents, bacterial and fungal population and soil enzymatic attributes. The crop residue treatments favourably influenced the soil parameters over the control. Crop residue incorporation or burning significantly increased soil available potassium, microbial biomass, enzymatic activities and organic carbon when compared with applications of chemical fertilizer alone, while total nitrogen content was increased by residue incorporation. However, green manuring and farmyard manure applications showed inferior responses compared with residue management treatment. It is therefore recommended that bioresources should be managed properly to warrant improvements in soil properties, nutrient recycling and the sustainability for crop productivity, in order to achieve sustainable development goals for climate action. [ABSTRACT FROM AUTHOR]

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The trial was conducted in light loamy Dystric Albeluvisol in Western Lithuania. The influence of mixture (80 % Trifolium pratense L. (Tp) cv. Liepsna + 20 % Phleum pratense L. (Pp) cv. Gintaras II) as green manure on the productivity of wheat was investigated in the organic farming system. No pesticides and mineral fertilisers were used in Cattle manure 60 t ha-1 was applied only. Red clover aftermath was used as green manure. Mineral fertilisers and pesticides according to plant needs and 60 t ha-1 of cattle manure were applied in the sustainable farming system. Perennial grasses were grown for hay. Independently of the farming system red clover content in sward during the trial execution was 98.0-99.4 %. The dry mater (DM) yield of red clover regrowth was low (1.17-1.24 t ha-1), because of the lack of precipitation. Higher winter wheat yield (6.72 t ha-1) was obtained from the sustainable farming system. Maintenance with nutrients was better in sustainable than in the organic farming system, where the wheat yield was 1.8 times lower. Less nitrogen and phosphorus (2.8 and 2.6 times respectively) were applied to soil with green manure in the organic farming system when compared with the sustainable farming system. [ABSTRACT FROM AUTHOR]

A 7-year-long field trial was conducted on integrated nutrient management for a dry season rice (Boro)-green manure (GM)-wet season rice (T. Aman) cropping system at the Bangladesh Rice Research Institute Farm, Gazipur during 1993-1999. Five packages of inorganic fertilizers, cow dung (CD), and GM dhaincha (Sesbania aculeata) were evaluated for immediate and residual effect on crop productivity, nutrient uptake, soil-nutrient balance sheet, and soil-fertility status. Plant height, active tiller production, and grain and straw yields were significantly increased as a result of the application of inorganic fertilizer and organic manure. Usually, the soil-test-based (STB) fertilizer doses for a high-yield goal produced the highest grain yield of 6.39 t ha-1 (average of 7 years) in Boro rice. Application of CD at the rate of 5 t ha-1 (oven-dry basis) once a year at the time of Boro transplanting supplemented 50% of the fertilizer nutrients other than nitrogen (N) in the subsequent crop of the cropping pattern. A positive effect of GM on the yield of T. Aman rice was observed. Following GM, the application of reduced doses of phosphorus (P), potassium (K), sulfur (S), and zinc (Zn) to the second crop (T. Aman) did not reduce yield, indicating the beneficial residual effect of fertilizer applied to the first crop (Boro rice) of the cropping pattern. The comparable yield of T. Aman was also observed with reduced fertilizer dose in CD-treated plots. The total P, K, and S uptake (kg/ha/yr) in the unfertilized plot under an irrigated rice system gradually decreased over the years. The partial nutrient balance in the unfertilized plot (T1) was negative for all the nutrients. In the fertilized plots, there was an apparent positive balance of P, S, and Zn but a negative balance of N and K. This study showed that the addition of organic manure (CD, dhaincha) gave more positive balances. In the T4c treatment at 0-15 cm, the application of chemical fertilizers along with the organic manures increased soil organic carbon by (C) 0.71%. The highest concentration of total N was observed with T4c followed by T4d and T4b, where CD was applied in Boro season and dhaincha GM was incorporated in T. Aman season. The sixfold increase in soil-available P in T4b-, T4c-, T4a-treated plots was due to the addition of CD. Dhaincha GM with the combination of chemical fertilizer helps to mobilize soil-available P by 3 to 6 ppm. The highest amount of soil-available S was found in T4c- and T4a-treated plots. It was 2.5 times higher than that of the initial soil. The application of CD and dhaincha GM along with chemical fertilizers not only increased organic C, total N, available P, and available S but also increased exchangeable K, available Zn, available iron (Fe), and available manganese (Mn) in soil. [ABSTRACT FROM AUTHOR]

Abstract: Soils at abandoned brick production sites are inherently low in fertility and have poor physical conditions. In order to develop efficient soil management practices for rapid restoration of these seriously degraded soils, a field experiment was conducted on an abandoned brick production site in Shaoxing county, Zhejiang province, southeast China. Amelioration methods, including tillage, fertilization and green manure (GM) cropping, were compared for their effects on improving selected soil quality indicators. Both fertilization and tillage improved chemical, biological and physical properties of the soils. Deep tillage significantly decreased soil bulk density and significantly increased infiltration rate. Use of organic manure and chemical fertilization increased soil nutrients and microbial biomass. Application of organic manure significantly increased levels of organic C and N and the formation of water-stable aggregates, as compared with application of chemical fertilizers. Deep tillage combined with application of organic manure and green manure cropping was the most efficient method for increasing quality of the soil. [Copyright &y& Elsevier]