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The ground cover produced by green manures has a direct influence on weed suppression and, in addition, the biomass produced by these same plants influences crop growth. This study was carried out to compare the effect of green manure species on the incidence of weeds, in sequence, in order to evaluate the effects of the use of green manure cover on the productive characteristics of maize plants. A completely randomised experimental design was used, with 11 treatments and 4 replications. The treatments were cover crops Canavalia ensiformis (T1), Cajanus cajan (T2), Stizolobium pruriens (T3), Crotalaria juncea (T4), Phaseolus vulgaris (T5), Stizolobium trigre (T6), Stizolobium aterrimum (T7), Crotalaria retusa (T8), Crotalaria breviflora (T9), Dolichos lablab (T10), and conventional system (T11). Ninety days after sowing, the green manures were cut, and 30 days after the green manures were cut, the hybrid maize Crop Top 520 was sown. The variables evaluated in relation to the planting of green manures were the green and dry biomass of green manures, alongside the green biomass of weeds and suppression of weeds. Concerning maize plants, the variables evaluated were plant height at 60 DAS, stalk diameter at 60 DAS, number of grain rows per ear, number of grains per grain row, and yield. The averages were subsequently analyzed using Tukey's test at 95% significance level. The use of green manure significantly reduces the green mass of weeds up to 90 days due to lack of access to light of the weeds, which reduces their appearance and growth. Stizolobium aterrimum showed the best results both as a dry mass producer and weed suppressor and also as a yield enhancer in maize crops. [ABSTRACT FROM AUTHOR]

Cereals and green manures intercropping contributes to sustainable agriculture as it combines food production with biomass for soil cover formation. This study aimed to evaluate the intercropping of rice and green manures effects on the agronomic and qualitative performance of rice, as well as dry mass yield for the no-tillage system. A two-year experiment with 8 treatments: rice as sole crop or intercropped with Arachis pintoi, Calopogonium mucunoides, Crotalaria breviflora, Crotalaria spectabilis, Stylosanthes capitata and macrocephala, Canavalia ensiformis, and Cajanus cajan was conducted in the Brazilian Cerrado region. The results showed that the shoot dry mass and height of plants was affected by the cultivated species. Rice intercropped with A.pintoi, C.mucunoides, C.breviflora, C.spectabilis and S.capitata and macrocephala promoted yield and grain quality similar to those found with rice as sole crop. Intercropping systems of rice with C.spectabilis, C.ensiformis and C.cajan increased the number of unfilled spikelets and reduced the number of filled spikelets and yield by 33, 24 and 58%, respectively. Intercropping systems with A.pintoi, C.mucunoides, C.breviflora, C.spectabilis, C.ensiformis and C.cajan produced adequate dry mass for the maintenance of soil cover in quality no-tillage system. [ABSTRACT FROM AUTHOR]

• Green manures are recommended for organic management of plants in high tunnel. • Rotary tillage, especially with fresh biomass mulch, has a positive effect on the yield of vegetable plants in high tunnel. • Ambiguous effect of green manures on the chemical composition of edible parts of vegetables was observed. Tunnel production is well suited to growing high-value crops, such as organic vegetables or fruits. Effects of cover crops integration into crop rotations were evaluated in an organic system in a high tunnel. In the research conducted at the Experimental Station of the University of Agriculture in Krakow, turnip and swede (rutabaga) sown in 2018, and phacelia and buckwheat, sown in 2020 in the second cycle, were used as green manure. The vegetable crop rotation included successive cultivation of pumpkin, romaine lettuce, broad bean, hot pepper (2018–2019), and leek and leaf parsley (2020–2021). The control was a plot without plants sown for green manure, covered with black polyethylene film during their cultivation. The effect of green manures on yielding and chemical composition of edible parts of vegetable plants was studied. The beneficial effect of turnip and swede was noticeable only in the autumn cultivation of romaine lettuce. The obtained yield was 63,3 % average higher. The significant effect on the yield of early broad bean was also shown. Grain yield was with 90,9 % higher in case of turnip and higher with 59,1 % in case of rutabaga than in the control plot. This trend was also observed in the cultivation of hot pepper. Its yield after rutabaga was with 189 % higher, and it was 102 % as high after the preceding crop of turnip compared to the control. Whole-plant of leeks yield, was higher (15,8 %) on the phacelia treatment in comparison with control. The total yield of parsley leaves was significantly higher in the plot following phacelia and buckwheat compared to the control (197 % in average). In general, the chemical composition evaluation did not find a clear impact of green manures. However, leeks grown in the control plot had the highest dry matter and vitamin C content. [ABSTRACT FROM AUTHOR]

The ability of adaptation of Rhizobia in diverse environment namely, soil, rhizosphere and grown within legume roots may lead to nitrogen fixation, in a complicated process which contain a coordinated exchange of signal between plants and the symbionts. Green manures, cash and cover crops have significant role in soil fertility. Green manuring techniques also can decrease biomass burning known as main source of air pollutant in the atmosphere. Catch crops have positive effects on both physical and chemical properties of soil, subsequent crop yield, decrease nitrogen leaching into the ground water, decrease soil erosion, and decrease nitrogen losses in cropping systems. Cover crops are those crops which cover the ground and protect loss of plant nutrients, the soil from erosion, decrease rate of soil moisture by evaporation, lower ground temperature and improve weed control and nutrient recycling. Rhizobia produce Nod factors during the early development of nodules upon perception of flavonoid molecules secreted by legume roots, and Nod factor's structure dependents on species, chemical, substitutions added which may influence legume specificity. The benefic effects of rhizobia may depend on rhizobium strain, the genotype of the legume, management practices and bio-physical environment. Rhizobium can directly promote both plant growth and plant health, and modulating root architecture and growth via the release of plant phytohormones. In this manuscript, we want to review the most important advantages and benefits of green manures, catch and cover crops with considering the positive effects of rhizobium on soil fertility and sustainable agricultural production. [ABSTRACT FROM AUTHOR]

Widespread use of legume green manures is limited by a lack of reliable varieties that meet the needs of farmers. Improving symbiotic N fixation (SNF) in open‐pollinated legume species poses a challenge because normal methods used for assessing SNF conflict with breeding practices such as seed production and removing low‐quality sires. We investigated methods for measuring symbiotic N fixation that are compatible with breeding practice for two major legume cover crops: hairy vetch (Vicia villosa Roth) and crimson clover (Trifolium incarnatum L.). We collected two nondestructive samples at the early‐flowering stage (Meristem and Wedge) and a sample at seed harvest (Seed). Our objective was to determine which combination of measurements best predicted symbiotic N fixation (% N derived from atmosphere [Ndfa]) and total N content at 50% flowering. Our statistical approach accommodated the problem that target traits and seed measurements cannot be measured in the same individuals. Overall, the Wedge sample provided the best prediction for Ndfa at 50% flowering. The best predictions for total N plant–1 came from combining vigor ratings with aboveground biomass at seed harvest. In addition to specific recommendations for legume cover crop breeding programs, we provide a flexible statistical method for studying relationships between traits that cannot be measured jointly. Core Ideas: Symbiotic N fixation (SNF) was highly variable within two legume species.We identified the best nondestructive methods for predicting farmer‐relevant SNF traits.The best proxy for Ndfa at 50% flowering was 15N in a Wedge sample at early flowering.Total N yield was best predicted by typical breeding indicators of plant size.We present novel tools for analyzing traits that cannot be measured in the same individuals. [ABSTRACT FROM AUTHOR]

Annual rotation green manure crops of selected brassicas, buckwheat, forage pearl millet, forage radish, black-eyed Susan, sesame, sudangrass, and velvetbean were evaluated to determine impacts on lesion nematode Pratylenchus penetrans and dagger nematode Xiphinema americanum populations densities. Canadian forage pearl millet ' 101'and 'Tifgrain 102' millet effectively controlled P. penetrans but increased population densities ofX. americanum. Black-eyed Susan (Rudbeckia hirta) and sudangrass 'Trudan 8' also reduced P. penetrans densites but notX. americanum. Rapeseed and other brassicas as a green manure reducedX. americanum densities but did not suppress P. penetrans. Brassica juncea 'Pacific Gold', B. napus 'Dwarf Essex', but not mustard 'Caliente' resulted in low densities ofX. americanum in soil. Velvetbean and sesame increased both P. penetrans and X. americanum population densities. A moderately suitable host plant such as buckwheat was ineffective in managing both P. penetrans and X. americanum populations. These results emphasize that suppressive effects of any given cover crop are nematode-specific, and that within a group of cover crops, e.g., the Brassicaceae, species and varieties can vary substantially in their effectiveness. If the rotation crop chosen is a good host for the nematodes present, it may exacerbate the problem instead of controlling it. [ABSTRACT FROM AUTHOR]

A field experiment was carried out at the Joniškėlis Experimental Station of Lithuanian Research Centre for Agriculture and Forestry in 2016--2018 to ascertain the effects of reduced tillage and the combinations of reduced tillage with soil improvement practices on soil organic carbon (SOC) and quantity and quality of humus in a clay loam. The following tillage systems were investigated: 1) deep ploughing (DP) at 21--23 cm depth (control), 2) shallow ploughing at 15--17 cm depth (SP), 3) ploughless tillage (at 10--12 cm depth) (PT), 4) ploughless tillage and aftereffect of lime sludge last incorporated in 2014 (PT + aLS), 5) ploughless tillage with cover crops for green manure (PT + GM) and 6) no-tillage with cover crop for winter mulch (NT + WM). The reduction of tillage intensity increased the contents of SOC and C in humic substances (HS) in the upper (0--10 cm) soil layer. The incorporation of organic sources in the form of green manure and winter mulch promoted microbiological activity and the mineralization of the soil organic matter (SOM) already present in it. However, the SOC and total nitrogen (Ntot) content did not increase in proportion to the fresh organic matter incorporated. The tillage systems applied had influence on the changes in the humus fractional composition. The increased content of plant residues under PT + GM and NT + WM treatments resulted in higher amounts of mobile HS in the upper soil layer, meanwhile the PT + aLS treatment increased the amount of agronomically most valuable Ca-bound HS. Higher amounts of HS bound with clay minerals were found under PT + aLS treatment, as calcium (Ca) is an important factor for SOC sequestration in a clay. The humification degree increased in 0--30 cm soil layer under all reduced tillage systems investigated compared to the DP (control). The use of soil improvers had a more significant effect than just reduction of tillage. However, due to the complexity of SOM a clear relationship between SOM qualitative characteristics and tillage practices applied was not identified. [ABSTRACT FROM AUTHOR]

In a two-year experiment, agroecological service crops (ASCs) introduction before organic zucchini and lettuce vs no-ASCs (CT), and two ASCs termination strategies (green manure, GM vs roller crimper, NT) were compared. The objective was to assess the environmental sustainability in a Mediterranean environment. Agronomic performance, energy analysis and carbon footprint were assessed. Although lower zucchini and lettuce yields than GM, the NT strategy was more sustainable than GM and CT, showing energy efficiencyof 0.64, 0.31 and 0.13%, respectively, and showing the highest carbon stored in the soil. NT can reach a good compromise between crop production and impact of agricultural activities. [ABSTRACT FROM AUTHOR]

Weeds are the component of biological diversity in the agricultural systems (agrobiodiversity) and one of the greatest limiting factors to efficient organic crop production. The goal of the experiment is to define the influence of organic agricultural practices on the dynamics of weed infestation, weed species diversity and community composition in organic potato field included in three-field crop rotation. The results show that all analyzed weed parameters are characterized by high dynamics during potato grown seasons. The biological development of weeds in the cover crop before incorporation to the potato field was strongly limited. According to the data obtained, cover crop for green manure and mechanical soil tillage in the organic potato field were effective practices for controlling the weed infestation. The effect of organic practices on the weed community parameters were assessed by ecological indexes (Shannon index (H'), Shannon-Wiener evenness index (J'), index of dominance (Simpson dominance index, D) and similarity indexes (Srensen similarity index, SSI). Results show that the studied three-field crop rotation included winter wheat, green bean, peas and rye mixture as cover crops and potato is a strategic scheme for achieving good weed control at the end of the rotation. The comparison of similarity of weed communities in a potato field between 2012 and 2013 using Srensen indices shows that the similarity was higher on the base of the qualitative index (35.3%) than of the quantitative ones (20.8%). [ABSTRACT FROM AUTHOR]

Reliable methods to estimate nitrogen (N) mineralization from organic amendments are needed to improve the fertilization recommendations for organic horticultural crops. With this aim, N mineralization from farmyard manure compost (FYMC), commercial organic fertilizer (COF) based on materials that are prompt to rapid N mineralization and green manure was determined in field situation where environmental factors affect mineralization rates and under controlled laboratory conditions that may not reflect conditions in the field. The ability of field and laboratory incubations to predict N mineralization was estimated during a field organic crop rotation set up with a cover crop of rye and vetch, followed by Portuguese cabbage and carrot. The relationship between mineralized N in field incubation and crop N accumulation suggests that field incubation is effective to predict N mineralization from FYMC, COF and green manure. However, the pattern of N mineralization from FYMC and green manure was different in field and laboratory incubation conditions as opposed to N mineralization from COF that was similar in both incubations. [ABSTRACT FROM AUTHOR]

Many factors are driving interest in improving soil health in potato production systems in the U.S. Pacific Northwest and beyond, including the need for enhanced sustainability and economic viability, and consumer preferences. Potato production poses a particular challenge in terms of soil health due to intensive tillage, minimal residue left on fields, short rotations, and the importance of managing soilborne pathogens. This review discusses existing soil health assessment methods and their relevance for the region and summarizes results of studies conducted in the Pacific Northwest and beyond, examining practices aimed at improving soil health and their effects on soil health, soilborne pathogens, yield and quality of potatoes, and net returns in potato production systems. These practices include reducing tillage; adjusting crop rotation length and species composition; reducing fumigation; and using cover crops, green manures, and organic amendments. [ABSTRACT FROM AUTHOR]

Spring-planted green manure cover crops may provide a nitrogen (N) benefit to a subsequent sweet corn (Zea mays L.) crop, but spring growth and lack of consistent benefits documented in previous studies provide limitations to adoption. Berseem clover (BC; Trifolium alexandrinum) and chickling vetch (CV; Lathyrus sativus L.) are two legumes that could be beneficial when spring-seeded, but they have not been well studied in this context. The objectives of this study were to measure spring-seeded cover crop biomass and N yield, and the subsequent effects on sweet corn yield and response to N fertilizer. The study was conducted in 2014 and 2015, and the experimental design was a randomized complete block split-plot design with cover crop as whole-plot treatments [CV, BC, berseem clover and oat (Avena sativa) mixture (BC + O), oats, and no cover crop] and N rate as split-plot treatments. Cover crop growth and effects on sweet corn production varied greatly between years, with both cover crop and sweet corn biomass greater in 2015, although BC produced very little biomass (<0.7 Mg·ha-1) and thus is not recommended for spring seeding. In 2014, CV resulted in the lowest agronomically optimum N rates (AONRs) compared with no cover crop, suggesting a potential N credit when only having an N yield of 11.6 kg·ha-1, but this effect was not seen in 2015. There was also no evidence that oat would supply N to the subsequent crop. Overall, evidence is lacking that any spring-seeded cover crop will provide a consistent N benefit on sandy soil, and limitations to spring growth may preclude widespread adoption. [ABSTRACT FROM AUTHOR]

• Net primary production (NPP) as C input source was higher in rice cropping season than fallow season. • Mineralized C loss as C output source was much higher in cold fallow season than warm cropping season. • Net ecosystem C budget (NECB) was negative in the conventional farming system (NPK). • Cover cropping and its biomass incorporation significantly increased soil C stock. In temperate paddy fields, rice is generally cultivated under flooding for 100–140 days during summer season, and thereafter, the soil is left without management under dried soil condition during cold fallow season. In this area rice straw is mostly removed for cattle feeding. Therefore, soil organic carbon (SOC) stock could be decreased with conventional practices, but the seasonal changes of SOC stock have not been evaluated well. To investigate SOC stock changes in temperate rice paddy, two seasonal C balances during rice cropping and fallow season were compared by the net ecosystem C budget (NECB) in the chemical fertilizer (control) and two different green manure treatments for three years. In the control treatment only chemical fertilizer was conventionally fertilized for rice cropping, but maintained without human control during the fallow season. In two green manure treatments, barley and hairy vetch (hereafter, vetch) were cultivated during the fallow season, and their whole biomasses were incorporated before rice transplanting. The conventional soil management with only chemical fertilization decreased small level of SOC stock (minus 0.70–0.84 Mg C ha−1 y−1 of NECB), which was attributed by high harvest removal (approximately 70% of total C input) and mineralized C loss (30%). Cover cropping and its biomass recycling as green manure was effective to increase SOC stock. High C/N ratio of non-leguminous barley produced high biomass yield, and its biomass incorporation significantly increased SOC stock with 1.21–3.43 Mg C ha−1 y−1 of annual NECB. In comparison low C/N ratio of leguminous vetch application increased slightly SOC stock (0.17–1.34 Mg C ha−1 y−1 of NECB), due to low biomass productivity and high mineralized C loss. However, irrespective with fertilization background, approximately 70% of mineralized C loss were occurred during the cold fallow season. Rice grain yields were similar between the control and hairy vetch treatment, but around 10% lower in barley treatment. Conclusively, high C/N ratio of cover crop cultivation during the fallow season could be better to increase SOC stock in mono-rice paddy, but additional nutrient management to increase rice productivity should be developed for barley utilization as green manure. [ABSTRACT FROM AUTHOR]

Conservation practices such as green manures and no-tillage can reduce soil erosion, enhance soil biological activity, increase water storage in soils, and provide nitrogen (N) in support of winter wheat (Triticum aestivum L.). However, green manures utilize soil water during the summer months, and such water depletion may negatively impact production by wheat in ecoregions with limited water resources. This 5-year study quantified the impacts of tillage systems and green manures on water storage efficiency (WSE) during summer, water use efficiency (WUE), and grain yield of winter wheat. The study was conducted during 2011–2016 in the United States (US) Southern Great Plains (SGP). Three legumes as green manures (cowpea, pigeon pea, and soybean) were compared with summer fallow and three levels of applied inorganic N (0, 45 and 90 kg N ha-1) at wheat planting, under conventional and no-till cultivation. Summer WSE was significantly (P < 0.05) reduced in response to green manures; summer fallow was also inefficient in storing soil water. Grain yield and WUE of wheat were reduced in response to green manures compared to summer fallow during dry years but there were no differences during wet or normal rainfall years. No till significantly increased WSE under all treatments, and reduced evapotranspiration during a subset (either summer or wheat growing season) of years but did not affect amounts of soil water. Our results demonstrate replacing summer fallow in continuous systems of winter wheat with green manures have limited effects on improving water availability or efficiencies in water use by wheat. More-effective approaches for using green manures to support winter wheat in the SGP include opportunity cropping during years with adequate moisture to support double-cropping or utilizing more water-efficient legumes or cropping systems. • WSE, WUE, and wheat yield responses to different crop rotations were assessed. • Summer fallow was inefficient in storing precipitation water. • Replacing the summer fallow with cover crops did not increase WSE. • Planting cover crops helped to increase system WUE during normal or wet years. • Winter wheat yield response to cover crop biomass production was negatively linear. [ABSTRACT FROM AUTHOR]

Background and aims: Crucifers grown as cover crops are known to reduce sulphate leaching (S catch-crop service) and release large amounts of mineral sulphate for the subsequent cash crop once incorporated into the soil (S green-manure service). Crucifer-legume cover crop mixtures are effective to obtain high nitrogen related services, but few data exist on their performances for S-related services. Our study aimed to assess performances of a wide variety of bispecific crucifer-legume mixtures designed to provide soil S catch-crop and S green-manure services.Methods: A two-year field experiment was conducted at two sites near Toulouse, France (silt clay loam soil) and Orléans, France (sandy loam soil) in which cultivars from eight crucifer species and nine legume species were tested as sole and bispecific cover crops.Results: Crucifer-legume mixtures and crucifer sole cover crops provided the same level of S catch-crop service (12 kg S ha−1), significantly higher than that of legume sole cover crops (4 kg S ha−1). Similarly, crucifer-legume mixtures provided almost the same level of S green-manure service (5.5 kg S ha−1) as crucifer sole cover crops (6.5 kg S ha−1).Conclusion: Our results demonstrate the compatibility and complementarity of certain crucifer and legume species when grown together to provide S and N catch-crop and green-manure services. For a same cover crop species no strong cultivar effect has been highlighted in our growing conditions. [ABSTRACT FROM AUTHOR]

During the fallow period, crucifers grown as catch crops are known to effectively reduce nitrate leaching, while legumes act mainly as green manure by releasing large amounts of mineral nitrogen (N) for the subsequent cash crop once incorporated into the soil. Crucifer-legume cover crop mixtures could be an effective solution for obtaining these two ecosystem services because they combine advantages of both species. However, crucifers might be a poor companion crop due to their high competition for abiotic resources and a potential allelopathic effect on legumes when grown with them. The aim of our study was to assess performances of a wide range of bispecific crucifer-legume mixtures to provide both catch crop and green manure services. A two-year experiment was conducted at two sites (near Toulouse and Orléans, France) where cultivars from eight crucifer species (rape, white mustard, Indian mustard, Ethiopian mustard, turnip, turnip rape, radish and rocket) and nine legume species (Egyptian clover, crimson clover, common vetch, purple vetch, hairy vetch, pea, soya bean, faba bean, and white lupin) were tested in sole-crop and bispecific mixtures (substitutive design of 50%-50% sole crops). We measured cover crop biomass and N acquisition to assess the soil nitrate catch crop service and N green manure service for the subsequent cash crop. In all experiments, compared to bare soil, crucifer-legume mixtures and crucifer sole cover crops provided the same level of nitrate catch crop service by reducing soil mineral N by an average of 59%, while legume sole cover crops reduced it by at least 35%, which is significant. In addition, within 6 months after termination, crucifer-legume mixtures mineralised more N (mean of 22 kg N ha −1 ) and thus had a larger N green manure effect for the subsequent cash crop than crucifer sole cover crops (mean of 8 kg N ha −1 ). This was due to greater N acquisition and a lower C:N ratio of crucifer-legume mixtures; even though crucifers always had advantage in acquiring N, legumes acquired enough N to provide an effective green manure service. These results were consistent in all of our experiments, which represent a wide range of crucifer-legume cover crops, demonstrating their generality. They also demonstrate the compatibility and complementarity of these species when grown together. In conclusion, combining crucifers and legumes as cover crops is an effective solution for obtaining multi-ecosystem services related to N recycling by providing both nitrate catch crop and N green manure services. [ABSTRACT FROM AUTHOR]

Winter cover crops may provide different environmental benefits in agricultural systems. The aim of this study was to determine the effect of cover crops used as green manure on the soil nitrogen (N) budget and yield of silage maize (Zea mays L.). A field experiment was conducted between 2011 and 2013 at three locations in Vojvodina Province, Serbia. It compared common vetch (Vicia sativa L.), triticale (× Triticosecale Wittm. ex A. Camus), their mixture grown as cover crops, N fertilisation at two doses (N1 and N2), and an unfertilised fallow as a control. Cover crops were sown in autumn 2011 and 2012 and were ploughed in during May of the year after which silage maize was sown. Results show that the ability of cover crops to provide benefit for a subsequent crop is highly related to weather conditions, mainly precipitation. The two years of the study experienced completely different weather conditions, showing two aspects of how cover crops can affect subsequent crop yield and amount of N left in the soil. In 2012, the N budget was higher in all three cover crops at all locations than N1 and the control because of unfavourable weather conditions for mineralisation of organic matter. However, the cover crops had a negative effect on silage maize yield. In 2013 (an average year), the N budget was significantly higher after cover crops, and was followed by a higher yield of silage maize. Based on the 2-year average, the highest value of apparent N remaining in the soil was recorded in the mixture treatment (288.13 kg N ha-1); treatments with vetch and triticale had approximately equal values (272.17 and 272.71 kg N ha-1). The N fertilisation treatments and the control had significantly lower average values of residual N. [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]

Paraguay faces significant generational challenges in its agricultural industry, especially challenges in subsistence farming practices. Landless or smallholder farmers are less likely to adopt or use long-term soil management practices such as green manure and cover crop technologies. The purpose was to examine factors affecting adoption of green manure and cover crop technologies among Paraguayan smallholder farmers. Farmer training events, access to green manure and cover crop information, social participation, technical assistance (extension), and using chemical fertilizer significantly influenced, albeit weakly, farmers’ adoption of conservation agriculture practices. The results support further research to effectively refine agricultural adoption modeling. [ABSTRACT FROM PUBLISHER]

The aim of this study was to identify the cutting time for winter cover crops used as green manure in no-tillage systems that results in the highest dry weight yield (DWY) and nutrient accumulation. We testedAvena strigosa, Secale cereale, Vicia sativa, Raphanus sativus, andLupinus albus, in five management times, determining the fresh weight yield (FWY), DWY, and the chemical composition of the shoot tissue. The highest FWY was obtained usingR. sativusandL. albus. At 145 days after sowing; these species also had the highest DWYs, over 15 t ha−1.L. albusandS. cerealehad the highest carbon to nitrogen (C:N) ratio (60:1). The nutrient content of most crops decreased over time. However, the accumulation of nutrients increased over time, especially forR. sativus. L. albushad the highest level and manganese (Mn) accumulation, while the zinc (Zn) and cooper (Cu) accumulation was highest inA. strigosa, and that of boron (B) was highest inS. cereale. Thus,R. sativusprovided the best soil cover among the species tested, due to its high biomass yield and greater nutrient cycling. [ABSTRACT FROM AUTHOR]

Legume hairy vetch and non-legume barley mixtures are broadly cultivated to improve the value of cover crops in mono-rice paddies. Nevertheless, the effects of mixing conditions of the two cover crops on biomass and nutrient productivities and on the yield characteristics of subsequent rice crops have not been well studied. To evaluate the effects of mix-seeding legume and non-legume cover crops on the value of green manure in paddy soil, barley and hairy vetch were sown at the rice harvesting stage as pure crops at the recommended rates (180 kg ha −1 of barley, B100; 90 kg ha −1 of hairy vetch, V100), and as mixtures, in which the two cover crops were mix-seeded with varying seed ratios according to the replacement principle. The mixed seeding of the two crops significantly increased the cover crop biomass and nutrient productivities compared with the single barley and hairy vetch cultivation. Biomass productivity linearly increased with increasing barley seeding level, but it was not affected by the hairy vetch seeding rate. The total N content of the barley biomass clearly increased as the proportion of the total biomass accounted for by hairy vetch was increased, and this significantly improved the value of the green manure of cover crop biomass. In contrast, the total N content of the hairy vetch biomass was not affected by changes in the barley proportion. Biomass produced in the pure barley seeding could not produce the nutrients required by the recommended chemical fertilization level (N–P 2 O 5 –K 2 O = 90–45–57 kg ha −1 ) for rice, but the biomass increase caused by mixed seeding of the two cover crops resulted in enough nutrients to satisfy the recommended fertilization level. The highest biomass and nutrient yields were observed for the mixed seeding of barley and hairy vetch at 25 and 75% (B75V25) of their respective recommended seeding rates. This increased nutrient input stimulated the rice plant growth and significantly improved the rice yields. The highest yields were achieved with the B75V25 treatment. In conclusion, mixed seeding of legume hairy vetch and non-legume barley could be a very useful agronomic practice for increasing the cover crop biomass and its nutrient productivity and to improve the productivity of subsequent rice crops in temperate rice paddies. [ABSTRACT FROM AUTHOR]

Cover crop selection should be oriented to the achievement of specific agrosystem benefits. The cover crop, catch crop, green manure and fodder uses were identified as possible targets for selection. The objective was to apply multi-criteria decision analysis to evaluate different species ( Hordeum vulgare L., Secale cereale L., × Triticosecale Whim, Sinapis alba L., Vicia sativa L.) and cultivars according to their suitability to be used as cover crops in each of the uses. A field trial with 20 cultivars of the five species was conducted in Central Spain during two seasons (October–April). Measurements of ground cover, crop biomass, N uptake, N derived from the atmosphere, C/N, dietary fiber content and residue quality were collected. Aggregation of these variables through utility functions allowed ranking species and cultivars for each usage. Grasses were the most suitable for the cover crop, catch crop and fodder uses, while the vetches were the best as green manures. The mustard attained high ranks as cover and catch crop the first season, but the second decayed due to low performance in cold winters. Mustard and vetches obtained worse rankings than grasses as fodder. Hispanic was the most suitable barley cultivar as cover and catch crop, and Albacete as fodder. The triticale Titania attained the highest rank as cover and catch crop and fodder. Vetches Aitana and BGE014897 showed good aptitudes as green manures and catch crops. This analysis allowed comparison among species and cultivars and might provide relevant information for cover crops selection and management. [ABSTRACT FROM AUTHOR]

To determine the potential to suppress root-knot nematode Meloidogyne javanica, 10 genotypes of seven green manure species were evaluated in a greenhouse study. These species were: black hollyhock (Alcea rosea L.); canola (Brassica napus L.); cabbage (B. oleracea L.); French marigold (Tagetes patula L.), sorghum-sudangrass [Sorghum bicolor (L.) Moench nothosubsp. drummondii (Steud.) de Wet ex Davidse]; sunn hemp (Crotalaria juncea L.); and yellow mustard (Sinapis alba L.). Plants were inoculated with eggs of M. javanica and after 6 weeks, nematode eggs and reproduction factor (Rf = final egg population density/initial egg population density) were determined. Marigolds were non-hosts to M. javanica; other crop species that were poor hosts to M. javanica included canola cv. Dwarf Essex, sorghum-sudangrass cvs. Piper and Sordan 79, black hollyhock cv. Nigra, and sunn hemp. Based on low Rf, four groups of species were selected for further evaluation in the greenhouse to determine the response to both M. javanica and another crop pathogen, Pythium aphanidermatum. These four groups of green manure crops were: 1) seven marigold genotypes; 2) four Brassicaceae genotypes; 3) seven sorghum-sudangrass hybrids; and 4) four other species [black hollyhock, sunn hemp, elecampane (Inula helenium L.), and black-eyed Susan (Rudbeckia hirta L.)]. Plants were inoculated with a factorial combination of M. javanica and P. aphanidermatum (none, each alone, and in combination) and repeated four times in a split-plot experimental design (whole plots were factorial treatments and subplots were green manure crop genotypes). Six weeks after inoculation, plants were harvested and measured for fresh and dry weights of shoots and roots and Rf of M. javanica. Adverse effects of P. aphanidermatum were characterized by dead or dying roots and measured by reduced plant biomass. Negative synergistic effects were observed in several marigold and Brassicaceae genotypes, in which the combined effects of M. javanica and P. aphanidermatum reduced shoot and root growth more severely than either treatment alone. Marigold T. erecta cv. Orangeade, sorghum-sudangrass cvs. Graze-All, Piper, and Sordan 79, and sunn hemp appeared to be resistant to M. javanica and P. aphanidermatum, either alone or in combination. Based on results of greenhouse trials, eight green manure crops (yellow mustard cv. Ida Gold, French marigolds cvs. Nema-gone and Golden Guardian, sorghum-sudangrass cvs. Sordan 79 and Tastemaker, sunn hemp, unplanted plot, and a control plot with weed mat) were selected and grown for 3 months in a field trial in Pepeekeo, HI. Each treatment was replicated four times in a randomized complete block design. Shoot biomass was sampled at 1, 2, and 3 months after planting. Plant-parasitic nematodes were counted before planting and at 4 months after planting. Dry weight biomass averaged across three sampling dates was greatest for the two sorghum-sudangrass hybrids followed by those of two marigold cultivars that did not differ from them. No significant differences in populations of root-knot nematodes were found. Based on this field trial as well as greenhouse trials, marigold cultivars, sorghum-sudangrass hybrids, and sunn hemp appeared to be non-hosts or poor hosts to reniform (Rotylenchulus reniformis) as well as root-knot nematodes and well adapted to the environmental conditions found along the Hamakua Coast of the Hawaii Island. [ABSTRACT FROM AUTHOR]

Conventional agriculture strongly alters soil quality due to industrial practices that often have negative effects on soil life. Alternative systems such as conservation agriculture and organic farming could restore better conditions for soil organisms. Improving soil life should in turn improve soil quality and farming sustainability. Here, we have compared for the first time the long-term effects of conservation agriculture, organic farming, and conventional agriculture on major soil organisms such as microbes, nematofauna, and macrofauna. We have also analyzed functional groups. Soils were sampled at the 14-year-old experimental site of La Cage, near Versailles, France. The microbial community was analyzed using molecular biology techniques. Nematofauna and macrofauna were analyzed and classified into functional groups. Our results show that both conservation and organic systems increased the abundance and biomass of all soil organisms, except predaceous nematodes. For example, macrofauna increased from 100 to 2,500 %, nematodes from 100 to 700 %, and microorganisms from 30 to 70 %. Conservation agriculture showed a higher overall improvement than organic farming. Conservation agriculture increased the number of many organisms such as bacteria, fungi, anecic earthworms, and phytophagous and rhizophagous arthropods. Organic farming improved mainly the bacterial pathway of the soil food web and endogeic and anecic earthworms. Overall, our study shows that long-term, no-tillage, and cover crops are better for soil biota than periodic legume green manures, pesticides, and mineral fertilizers. [ABSTRACT FROM AUTHOR]

Research was carried out during 2008-2010 at the Joniškėlis Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry on a clay loam Endocalcary-Endohypogleyic Cambisol (CMg-n-w-can). The aim of the present study was to determine effects of deep (20-23 cm) and shallow (15-17 cm) ploughing, ploughless tillage (10-12 cm), combinations of ploughless tillage (10-12 cm) with incorporation of lime sludge and cover crop (mixture of field pea, common vetch and blue lupine) for green manure and application of the same cover crop for mulch without autumn tillage on soil physical properties and growth of spring oilseed rape (Brasica napus L.) crop. After shallow ploughing the soil water content in seedbed (0-5 cm) for spring oilseed rape right after its sowing was significantly lower in droughty years (with duration of post-sowing period without rainfall for 18 and 20 days in 2008 and 2009, respectively) and crop emergence was worse compared to deep ploughing. Due to ploughless tillage, the soil water content in seedbed was significantly lower in droughty years and seedbed structure was worse in sufficiently wet year compared to deep ploughing. Incorporation of lime sludge by ploughless tillage resulted in significantly higher soil water content at 5-15 cm depth, better seedbed structure and greater crop germination rate compared to ploughless tillage alone. Incorporation of lime sludge also increased oilseed rape yield by 11.1% in droughty year. Having incorporated the cover crop for green manure late in autumn by ploughless tillage the oilseed rape in droughty years germinated significantly worse, the soil water content remaining in the seedbed after emergence was lower and the yield decreased by 19.8% compared to ploughless tillage. Having left the cover crop mulch over winter without autumn tillage demonstrated significantly higher soil water content at 5-15 cm depth after oilseed rape sowing; however, in droughty years the seedbed became drier, its structure deteriorated, the crop germinated worse and yield decreased by 12.1-17.3% compared to ploughless tillage. Spring oilseed rape germination rate in droughty years was influenced by the soil water content in the seedbed after sowing (r = 0.56, P < 0.01), content of 2-5 mm soil aggregate fraction in seedbed (r = 0.50, P < 0.05) and by the seedbed structure, expressed as an index (r = 0.50, P < 0.05), while crop yield - by the seedbed structure (r = 0.67, P < 0.01) and by the germination rate (r = 0.74, P < 0.01). [ABSTRACT FROM AUTHOR]

Triploid watermelon cultivars are grown on more than 2,023 ha in Maryland and in Delaware. Triploid watermelon cultivars have little host resistance to Fusarium wilt of watermelon {Fusarium oxysporum f. sp. niveum). The effects of four different fall-planted cover crops (Vicia villosa, Trifolium incamatum, Secale cereale, and Brassica juncea) that were tilled in the spring as green manures, and bare ground, were evaluated alone and in combination with the biocontrol product Actinovate (Streptomyces lydicus) on Fusarium wilt severity and watermelon fruit yield and quality. Six field experiments were conducted over 3 years in Beltsville and Salisbury, MD and Georgetown, DE. Both V. villosa and T. incarnatum significantly sup-pressed Fusarium wilt of watermelon as much as 21% compared with watermelon in nonamended plots. However, no suppression of Fusarium wilt occurred at low disease levels or where low cover crop biomass was present. In general, Beltsville, MD had lower disease levels than Salisbury, MD and Georgetown, DE. T. incarnatum was the only cover crop that yielded significantly more fruit than nonamended treatments (129% more fruit per hectare) but only for one field trial. The Actinovate product either did not reduce Fusarium wilt or the magnitude of the reduction was nominal. Actinovate significantly reduced Fusarium wilt by 2% in 2009 and as much as 7% in 2010, and increased Fusarium wilt severity by 2.5% in 2011. Actinovate signifi-cantly increased yield for one field trial but only when applied to non-amended or Secale cerea/-amended plots. This is the first report of a reduction in Fusarium wilt following a T. incarnatum cover crop incor-porated as a green manure. [ABSTRACT FROM AUTHOR]

Highlights: [•] Decay rate of cover crop biomass was high in deep green manure and low in mulch strip. [•] Hairy vetch residues have a long-term effect on soil mineral N and vegetable yield. [•] Oat and oilseed rape residues had no long-term effects on soil N and vegetable yield. [•] Placing hairy vetch residues in mulch strips provides a long-term soil N availability. [Copyright &y& Elsevier]

In a 3-year experiment, the effect of catch crop management [catch crop incorporated in autumn (A) or mulched (B) vs plots without a catch crop (C)] on soil acid (PAC) and alkaline (PAL) phosphatase activities as well as on the available phosphorus content (PAVAIL) were investigated on typical Alfisol. The catch crops were sown at the beginning of August and ploughed in the autumn in 2008, 2009, and 2010, or left as mulch during the winter. Soil samples were taken four times a year from spring barley plots that were grown in 2009, 2010, and 2011. Generally, catch crop treatment significantly influenced the enzymatic activity as compared to the control. The PAC activity was significantly greater with a mulched catch crop than in a ploughed one only in I and II sampling dates, whereas the PAL activity was not influenced by the method and time of field pea management. The time of sampling significantly influenced the PAL activity in 2011 and the PAC activity in 2009 and 2011. [ABSTRACT FROM AUTHOR]

Highlights: [•] The aim was to set up agroecological indicators to assess the mineralization of green manure. [•] Soil treated with rye grass green manure is not significantly different from control soil. [•] Common vetch green manure promotes CO2 emission, enzyme activity, nitrogen release. [•] The mineralization results as a combined effect of climatic conditions and crop residues quality. [•] In a Mediterranean area the high monthly aridity index at green manuring time promotes soil mineralization. [ABSTRACT FROM AUTHOR]

Trials with large-leaved lupine ('Lupi') and early red clover ('Jõgeva 433') as green manure were carried out to study their suitability for green manure production. The trials were carried out on the trial fields of the Estonian University of Life Sciences in 2008-2010. Biomass production abilities of various plants grown with or without a cover crop were examined. In the experiment, different green manure crops with undersowing and pure sowing were compared for amounts of N, C, P, K and organic matter driven into soil and their effect on cereal yield. The value of these green manure crops as manure was estimated, based on their effect on the succeeding cereal yield. From green manure plants, sown with cover crops, red clover gave the best results, while large-leaved lupine was better grown as pure crop (18% more biomass than red clover in similar situation). Biomass from large-leaved lupine, grown without cover crop, was also the most efficient in returning nutrients into the soil. Pure green manure had bigger effect and it lasted longer if grown as undersowing. [ABSTRACT FROM AUTHOR]

Background and aims: Winter cover crop cultivation during the fallow season has been strongly recommended in mono-rice paddy soil to improve soil quality, but its impact in increasing the greenhouse gases (GHGs) emissions during rice cultivation when applied as green manure has not been extensively studied. In order to recommend a preferable cover crop which can increase soil productivity and suppress GHG emission impact in paddy soil, the effect of winter cover crop addition on rice yield and total global warming potential (GWP) was studied during rice cultivation. Methods: Two cover crops (Chinese milk vetch, Astragalus sinicus L., hereafter vetch, and rye, Secale cerealis) having different carbon/nitrogen (C/N) ratios were cultivated during the rice fallow season. The fresh above-ground biomasses of vetch [25 Mg fresh weight (FW) ha, moisture content (MC) 86.9 %, C/N ratio 14.8] and rye (29 Mg rye FW ha, MC 78.0 %, C/N ratio 64.3) were incorporated as green manure 1 week before rice transplanting (NPK + vetch, and NPK + rye). The NPK treatment was installed for comparison as the control. During the rice cultivation, methane (CH) and nitrous oxide (NO) gases were collected simultaneously once a week using the closed-chamber method, and carbon dioxide (CO) flux was estimated using the soil C balance analysis. Total GWP impact was calculated as CO equivalents by multiplying the seasonal CH, CO, and NO fluxes by 25, 1, and 298, respectively. Results: Methane mainly covered 79-81 % of the total GWP, followed by CO (14-17 %), but the NO contribution was very small (2-5 %) regardless of the treatment. Seasonal CH fluxes significantly increased to 61 and 122 % by vetch and rye additions, respectively, compared to that of the NPK treatment. Similarly, the estimated seasonal CO fluxes increased at about 197 and 266 % in the vetch and rye treatments, respectively, compared with the NPK control plots. Based on these results, the total GWP increased to 163 and 221 % with vetch and rye applications, respectively, over the control treatment. Rice productivity was significantly increased with the application of green manure due to nutrient supply; however, vetch was more effective. Total GWP per grain yield was similar with the vetch (low C/N ratio) and NPK treatments, but significantly increased with the rye (high C/N ratio) application, mainly due to its higher CH emission characteristic and lower rice productivity increase. Conclusions: A low C/N ratio cover crop, such as vetch, may be a more desirable green manure to reduce total GWP per grain yield and to improve rice productivity. [ABSTRACT FROM AUTHOR]

Abstract: Cover crop cultivation during the cold fallow season has been strongly recommended in mono-rice cultivation system to improve soil quality. Its addition as green manure could stimulate methane (CH4) emission in the submerged paddy soil during rice cultivation, but its effect has not been evaluated well. Leguminous Chinese milk vetch (hereafter milk vetch) and non-leguminous rye were seeded after rice harvesting in 2008 and 2009, and total above-ground biomasses were incorporated with the recommended mineral fertilizers (NPK+milk vetch, and NPK+rye, respectively) before rice transplanting in 2009 and 2010. No fertilization (control) and mineral fertilization alone (NPK) plots were installed for comparison. Methane flux which was investigated by the closed chamber method during rice cultivation was significantly increased by chemical fertilization to ca. 80–250% over the control (138–141kgCH4 ha−1), but increased more markedly by cover crop biomass addition to ca. 28–121% over the NPK treatment. Milk vetch was more effective on stimulating less CH4 emission (28–61% increase over NPK) and improving rice productivity (18–31% increase over NPK) than rye (86–121% increase of CH4 emission and −3–6% of yield increase over NPK). As a result, the total CH4 flux per grain yield was significantly increased by rye addition, but were similar between the NPK+milk vetch and NPK treatments. Conclusively, low C/N ratio cover crop like milk vetch might be more recommendable green manure to minimize CH4 emission impact and increase rice productivity than high C/N ratio cover crop like rye in paddy soil. [Copyright &y& Elsevier]

The objectives of this study were to assess the effect of cover crops grown as green manure on the dynamics of mineral nitrogen in the soil under organic vineyard. Field investigations were carried out on the experimental field of the Faculty of Agriculture in Novi Sad, which is located in Sremski Karlovci, Serbia. Winter cover crops were sowed in autumn 2009 and samples of soil, where mineral forms of nitrogen were present, were taken twice during the growing season in 2010 (spring and summer). Winter forage pea (Pisum sativum L.) and oilseed rape (Brassica napus L.), used as cover crops in an organic vineyard, showed the influence on the increase of mineral nitrogen in the soil. Plowing of the green mass of forage pea led to an intensive mineralization of organic matters which consequently caused positive balance of N. On the treatment with forage pea, content of mineral N at the end of the vegetation period was higher by 60 kg N ha-1 in comparison to the first measuring period (spring). The treatment with oilseed rape showed no significant differences in the measuring periods. With regard to the control treatment, this treatment did not have a negative balance of nitrogen but it was considerably lower in comparison to the forage peas and it was 5.93 kg N ha-1. Oilseed rape, used as a cover crop, is suitable for storing reserves of soil mineral nitrogen in winter and spring, when there is minimal need for nitrogen in the vineyard. Thus, nitrogen losses can be prevented. Apart from uptaking nitrogen from the soil, forage peas also fixate considerable amount of nitrogen from the air and additionally enriches soil with nitrogen. Cover crops use in viticulture is suitable since their vegetation partly overlaps with vineyards vegetation, thus it does not represent a problem for vine plants in the aspect of uptaking nitrogen from the soil. [ABSTRACT FROM AUTHOR]

Abstract: To address the decline in crop productivity in the drylands of West Africa, many initiatives have focused on combating soil degradation. Various practices including (1) parkland trees associated with crops, (2) coppicing trees, (3) green manure, (4) mulching, (5) crop rotation and intercropping, and (6) traditional soil/water conservation have been tested. The present study attempts to provide a comprehensive, quantitative synthesis of existing reports on the effect of conservation agriculture (CA) practices on crop yield response in Burkina Faso, Mali, Niger and Senegal. Out of a total of 155 reports found, 63 fulfilled all the appropriate criteria to be included in the meta-analysis of the effect of various conservation agriculture practices on the yield response of maize, millet and sorghum. The study revealed significant variability in cereal yield response (and hence risk) with all the practices examined. Despite the variability, the mean effects of the six CA practices on crop yield were more positive than negative except with parkland trees. However, for this last practice, species like Faidherbia albida exerts more positive impact on crop yield. Yield increases relative to the control were higher with green manure and mulching than with coppicing trees and parklands. Increases in yield in the six CA practices were higher on low to medium productivity sites for maize, millet and sorghum. Coppicing trees and rotations improved yields when the rainfall is >800 mm whereas the opposite happens with parkland and soil–water conservation measures. Mulching performed better when the rainfall is <600 mm. The variability (and hence yield risks) calls for more understanding of the processes and application of appropriate tree management to reduce crop yield losses while still providing products (fruits, leaves, wood, etc.) and services (soil carbon building up) for long-term sustainability of the production systems in drylands of West Africa. [Copyright &y& Elsevier]

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]

Field experiments were carried out in Central Italy on several green manure species (pure or mixed) and on succeeding grain maize to find practical relationships for predicting the N effect (N absorbed by maize that derives from the actual gain in soil available N due to green manure). Actually, little information is available for Mediterranean environments, where green manure species and strategies may be other than those of northern-temperate and tropical regions. Relationships were found for maize shooting (Neff = -3.61DW + 29.75N%; R2 = 0.67), flowering (Neff = -1.32DW + 27.47N%; R2 = 0.66) and physiological maturity (Neff = -4.84DW + 50.43N%; R2 = 0.74) (DW = incorporated biomass, N% = N concentration). [ABSTRACT FROM AUTHOR]

Abstract: The benzoxazinoid 2,4-dihydroxy-1,4-benzoxazin-3-one (DIBOA) is produced by rye (Secale cereale) and may contribute to plant-parasitic nematode suppression when rye plants are incorporated as a green manure. We investigated the fate of DIBOA in soil and DIBOA''s effects on nematode reproduction. Soil in plastic bags was treated with DIBOA at concentrations ranging from 1.1 to 18 μg g−1 dry soil, and with the root-knot nematode Meloidogyne incognita. Control soils were treated with water or with 0.31% methanol, with or without nematodes. DIBOA concentrations extracted from the soil were measured at selected times for 5 consecutive days. The soil from each bag was then placed into a pot in the greenhouse, and a cucumber seedling was transplanted into each pot. Five weeks later, only the highest DIBOA concentration, 18 μg g−1 soil, reduced nematode egg numbers. At 0 h, DIBOA measured in soil ranged from 19.68 to 35.51% of the initial DIBOA concentration, and was dependent on the concentration added to the soil. DIBOA half-life was from 18 to 22 h, and very little DIBOA was present in soil after 120 h. Identified breakdown products accounted for only 4% at maximum of the initially added DIBOA. The results of our study demonstrate that high soil concentrations of DIBOA are necessary to suppress M. incognita; DIBOA may not be a major factor in nematode suppression by a rye cover crop. [Copyright &y& Elsevier]

In low input (e.g. organic) farming systems where soil phosphorus (P) fertilisers such as superphosphate are not used, maintaining sufficient available soil P for plant growth can be a major challenge. The use of P accumulating cover crops may increase P availability for subsequent crops. We hypothesised that P release from organic residues of legumes (faba bean ( Vicia faba) and field peas ( Pisum sativum)) could supply adequate P to meet the needs of a subsequent crop in a low P soil. A pot experiment was conducted to determine the contribution of P by legume green manure to subsequent corn using 33P labelled legume residues and 32P labelled inorganic fertiliser (KH2PO4). The treatments included two rates of P application, (a) 10 kg P ha−1 as legume root and shoot residues or as inorganic fertiliser with and without a C source, and (b) 38 kg P ha−1as a combination of legume shoot and root residues or a combination of root and inorganic fertiliser and inorganic fertiliser alone. An absolute control (zero P) was also used. Shoot dry matter, P uptake and P source (residues or fertilisers) of total P in corn were measured at harvest. Faba bean and field pea residues alone or in combination with fertilisers contributed up to 10% and 5% of the total P uptake by corn respectively, compared with up to 54% by inorganic fertilisers. Incorporation of field pea and faba bean residues with P concentrations higher than those observed under field conditions, may not always lead to adequate net P release to supply the early growth phase of subsequent crops. [ABSTRACT FROM AUTHOR]

• Cropping system management strategy significantly affects many soil properties. • Longer rotations with reduced tillage improved soil structural attributes. • Compost amendment had the greatest effect on improving multiple soil health parameters. • Combining multiple soil health practices into cropping systems provided the best results. • Cropping system effects on soil properties generally increased over time. Soil health is essential for agricultural sustainability and environmental quality yet may be degraded by intensive cropping practices. Improved cropping systems and management practices may greatly enhance soil properties associated with soil heath. Four different potato cropping systems, designed to address specific management goals of soil conservation (SC), soil improvement (SI), disease suppression (DS), and a status quo standard rotation (SQ), along with a non-rotation (PP) control, were evaluated for their effects on soil physical, chemical, and biological properties in field trials in Maine, USA. The purpose of the study was to determine how and to what extent these different cropping system approaches and practices would affect soil properties. Cropping systems were established in 2004 and actively managed through 2010, with potato crops also planted in subsequent years (2011−12) to examine residual effects. Cropping system significantly affected many parameters associated with soil health, with effects generally increasing over time as well as having lasting residual effects. All rotations increased aggregate stability, water availability, microbial biomass C, and total C and N compared to no rotation (PP), and 3-yr systems (SI, SC, DS) increased aggregate stability relative to the 2-yr system (SQ). The 3-yr systems with reduced tillage (SI and SC) also increased water availability and reduced bulk density relative to the other systems. However, the SI system, which included yearly compost amendments, resulted in greater increases in total and particulate organic matter (POM) C and N, active C, microbial biomass C, water availability, CEC, concentrations of P, K, Ca, Mg, and S, and lower bulk density than all other rotations. Cropping systems that incorporate management practices such as increased rotation length and the use of cover crops, green manures, reduced tillage, and, particularly, organic amendments, can improve soil physical, chemical, and biological properties associated with soil health. [ABSTRACT FROM AUTHOR]

• Evaluation of green manure application effect by meta-analysis. • Green manure can significantly improve soil nutrient content. • Green manures' type affects succeeding crops yield. The application of green manure is a traditional and valuable practice for agroecosystem management. In northern China, the effects of green manure on production of the region's major crops have been extensively investigated, but the inconsistent conclusions that these case studies have yielded cannot provide effective guidance for practical local agricultural production. Here, we conducted a meta-analysis to generate a comprehensive evaluation of the effects of green manure on soil properties and crop yield in this region. Our results shown that green manure improves soil quality effectively, decreasing soil bulk density by ∼ 5.6 %, increasing microbial biomass carbon by 28 %, and improving the activities of soil enzymes by 14 % ∼ 39 %. Among the different types of green manure, legume green manure more markedly increased both nitrate and hydrolysable nitrogen, while non-legume green manure more markedly increased available potassium. Soil gravimetric water content was decreased under green manure treatment. Maize yield was significantly increased under green manure by 11 % on the whole, while effects of green manure on wheat and potato were inconsistent. In summary, the application of green manure in northern China can improve soil quality significantly, and proper green manure use can improve cash crop yields. [ABSTRACT FROM AUTHOR]

Cropping systems and management practices that improve soil health may greatly enhance crop productivity. Four different potato cropping systems designed to address specific management goals of soil conservation (SC), soil improvement (SI), disease suppression (DS), and a status quo (SQ) standard rotation, along with a non-rotation (PP) control, were evaluated for their effects on potato crop growth, nutrient, and yield characteristics under both irrigated and non-irrigated (rainfed) conditions in field trials in Maine, USA, from 2004 to 2010. Both cropping system and irrigation significantly (p < 0.05) affected most potato crop parameters associated with growth and yield. All rotations increased tuber yield relative to the non-rotation PP control, and the SI system, which included yearly compost amendments, resulted in overall higher yields and a higher percentage of large-size tubers than all other systems with no irrigation (increases of 14 to 90%). DS, which contained disease-suppressive green manures and cover crops, produced the highest yields overall under irrigation (increases of 11 to 35%). Irrigation increased tuber yields in all cropping systems except SI (average increase of 27–37%). SI also resulted in significant increases in leaf area duration and chlorophyll content (as indicators of photosynthetic potential) and root and shoot biomass relative to other cropping systems, particularly under non-irrigated conditions. SI also resulted in higher shoot and tuber tissue concentrations of N, P, and K, but not most micronutrients. Overall, cropping systems that incorporate management practices such as increased rotation length and the use of cover crops, green manures, reduced tillage, and particularly, organic amendments, can substantially improve potato crop growth and yield. Irrigation also substantially increased growth and yield under normal field conditions in Maine, but SI, with its large organic amendments, was essentially a substitute for irrigation, producing comparable results without irrigation. [ABSTRACT FROM AUTHOR]

Long term incubation studies to determine the nitrogen (N) mineralization rates and kinetics in soils freshly amended with some commonly used green manures such as Seshania rostrata, Gliricidia maculata, Leucaena leucocephala and Azolla pinnata are scarce. A long term aerobic study was, therefore, conducted by incubating soils freshly amended with the above-mentioned green manures in PVC columns at 35 ± 1°C and with 0.01 Mpa moisture content. The soils were then leached at periodic intervals for up to 36 weeks. The N-mineralization rates were greatest during the first week and decreased with time in all soils. The green manure amended soils leached 247 mg kg-1 more NO3 + NO2 - N than the unamended control. In general, the total N mineralized (mean 61%) was almost twice that of net N mineralized (mean 30%) in the amended soils. The percent N mineralized (total and net), however, varied with the nature of green manure incorporated into the soil. It was greatest in the soil amended with sesbania and lowest in the soil amended with azolla. The kinetic parameters derived using the double exponential model indicated that green manure amended soils possessed significantly higher N-mineralization potentials and rate constants compared to the unamended control. The kinetic parameters also varied with the nature of green manure incorporated into the soil. Among the various parameters lignin content, lignin to N ratio and lignin + polyphenol to N ratio of the green manures were the key factors governing the rate of decomposition and subsequent N mineralization from the amended soils. [ABSTRACT FROM AUTHOR]

• Whole-year leguminous green manure crops can reduce the weed seed bank in subsequent crops. • Weed seed bank reduction may reach 65 % at the time of termination of a green manure crop. • The legacy effect on the seed bank is still substantial three years after termination. • Periods with green manure crops can be important for the management of soil fertility and weeds in organic cropping systems. Leguminous green manure crops are important for accumulating nitrogen by means of biological nitrogen fixation and for building up soil fertility in organic arable cropping systems. Whole-year green manure crops are also known to deplete the soil weed seed bank, e.g. by decaying and predation, but there is uncertainty about the magnitude of the legacy effect after termination of the green manure crop. This study sampled soil for weed seed bank assessment upon termination of a two-year leguminous green manure crop and then one, two and three years afterwards. The samples were taken from two five-year crop rotations (2011–2015) in a long-term organic crop rotation experiment in Denmark. One rotation (O2) had a two-year green manure crop followed by three years of annual cash crops, and the other rotation (O4) consisted only of annual cash crops, with four crop sequences in both rotations represented every year. In general, the weed seed bank of rotation O2 was 54 % lower than O4, with 5475 seeds m−2 versus 11,967 seeds m−2. Similarly the aboveground amount of weed biomass in O2 was lower than in O4 over the course of the five years. The legacy effect of the green manure crop showed a negative exponential rise in weed seed numbers with the increase in years after termination of the green manure crop. A biennial leguminous green manure crop can mitigate weed problems in organic annual crops. This effect adds to the benefits of including nitrogen fixing leys in crop rotations with limited access to animal manures. [ABSTRACT FROM AUTHOR]

• Limited nitrogen availability after roller-crimping reduced cabbage yields. • Late termination of cover crops reduced nitrogen availability for cabbage. • Sufficient fertilisation maintained cabbage yield under roller-crimping. • Termination time and method of cover crops did not affect nitrogen leaching risk. • Roller-crimping changed resource allocation between shoot and root growth of cabbage. Agro-ecological service crops (ASCs), also known as cover crops, green manures or catch crops, can improve organic vegetable production in terms of weed suppression, nitrogen (N) recycling, or addition of N through symbiotic N 2 fixation by legumes. Traditionally, ASCs are terminated through full incorporation into the soil (FI), but alternative termination without tillage is available by roller-crimping (RC). The applicability of RC to Northern and Western European climates has only been studied to a limited extend. The objective of this study was therefore to investigate the N dynamics involved in FI and RC of legume and cereal ASCs in organic cabbage production across Northern and Western European climates. Field experiments were conducted at one location in Estonia and in Denmark, and at three locations in Belgium during two cropping cycles (2015/2016 and 2016/2017) to assess the effect of ASC termination method in spring (FI and RC) and ASC species (pea, pea/cereal mixtures and cereals), compared with a bare soil control (BS), on soil mineral N content, N accumulation, yield, and root growth of a following crop of cabbage. Agro-ecological service crops, and in particular cereals, reduced N availability for succeeding cabbage compared with BS by 37–73%. Similar marketable cabbage yield was obtained under FI and BS in two out of four cases in Belgium, due to higher availability of soil mineral N when terminated earlier (April/May) than RC (May/June). However, FI reduced marketable yields by 36–98 % in the other cases in Belgium and in two out of four cases in Estonia and Denmark, where FI was conducted in May/June. Overall, cabbage marketable yields were reduced by 68–100% under RC compared to BS and FI in seven out of nine cases mainly due to reduced soil mineral N availability. Soil mineral N availability was lower under RC likely because of a slower mineralisation of ASCs and soil organic matter. Besides, the termination of ASCs close to the time of cabbage planting under RC increased pre-emptive competition on N. Cabbage marketable yield could be maintained under RC at fertilisation by 236 kg N ha−1 following pea in Denmark. Cabbage root growth was generally increased with higher above ground plant biomass across treatments in Estonia and Denmark, while the relationship was reverse under RC in East Flanders, indicating changes in resource allocation. Soil mineral N at harvest did not differ among treatments in deeper depth, showing no higher risk of N leaching from FI or RC. In conclusion, RC showed major yield reductions in the first and second year after conversion from spring tillage. Therefore, further investigations should verify improved yields under longer-term RC practice, e.g. due to build-up of soil organic matter, before implementation can be recommended in organic vegetable production in Northern and Western Europe. [ABSTRACT FROM AUTHOR]

The aim of this experiment was to evaluate the effect of fertilizing processing tomato by coupling the green manuring of fall-winter cover crops with fertigation in spring-summer. In a two-year experiment, seven fertilization treatments were compared: green manuring of pure barley (B100) and pure vetch (V100) sown at 100% of their ordinary seeding rates, green manuring of a barley-vetch mixture at a ratio of 75:25 of their own seed rates (B75V25), fertigation with drip irrigation at a rate of 200 kg ha−1 of nitrogen (N) (Fert_N200), fertigation combined with B100 and B75V25 at a N rate complementary to 200 kg N ha−1 (B100 + Fert and B75V25 + Fert, respectively), and an unfertilized control (N0) with no cover crops for green manuring prior to tomato transplanting or fertigation. The Fert_N200 treatment resulted in maximum tomato N uptake, growth and yield, but caused high N leaching, especially during the no-cover fall-winter period, as was also the case for N0. The V100 treatment promoted quite good tomato N status and yield, but did not reduce N leaching. The B100 and B75V25 treatments reduced N leaching but decreased tomato N uptake, growth and yield. The B100 + Fert and B75V25 + Fert treatments reduced N leaching, likely increased soil N stock, and facilitated optimal tomato N nutrition and maximum yields. Combining fertigation with green manuring of cover crops composed of pure grass or grass-legume mixtures appears to be a very effective and environmentally sound practice for fertilizing high N-demanding spring-summer crops like processing tomato. [ABSTRACT FROM AUTHOR]

Sustainability of agricultural practices is one of the most important issues in organic agriculture and its assessment is crucial. To this aim, evaluating the balance between the energy inputs and outputs in crop rotations could be a valuable tool. Therefore, we compared different management strategies in a four-year organic cropping system, by estimating the energy balance of crop production. Two different living mulches with no-till (B1) and green manure (B2) were compared with a cropping system without cover crop (B3), performing both energy analysis and energy balance. Energy parameters were also evaluated. The energy input of fertilizers and water was more than 55% of the total energy required by the cropping systems, suggesting that these agronomic practices should be tailored by farmers to decrease total energy inputs. The potential energy output was significantly higher in the B1 than the B2 and B3 cropping systems (20% and 54%, respectively). Results indicated that B1 and B2 could enhance the energy outputs without negatively affecting the energy consumption, since these cropping systems also showed higher energy efficiency. The introduction of the cover crop as living mulch combined with no-till could be a powerful tool to enhance systems sustainability, without compromising the crop yields. [ABSTRACT FROM AUTHOR]

In sustainable or organic vineyard systems, the introduction of cover crops could represent a powerful tool for farmers to influence, positively, the agro-ecosystem by promoting the whole soil-plant system equilibrium. Concerning table grape production, nitrogen fertilizers are medium-high; for environmental aspects, organic viticulturists are more interested in legume inter-row cover crops. Research on cover crop effects was carried out in 2015–2016, on organic table grapes (the Sugranineteen variety) in Mediterranean conditions. Three inter-row soil management techniques were compared: (TR) inter-row spacing was cultivated with subterranean clover; (V) inter-row spacing with common vetch incorporated in the soil as green manure, and (RC) inter-row spacing with common vetch flattened by the roller crimper technique, making a living mulch. No significant difference was recorded in grapevine water status among the treatments. RC vines performed the highest net photosynthesis rate from shoot growth to veràison. Cover crops did not affect cluster weight, berry weight, and juice composition; however, they influenced berry detachment force. Our research findings confirmed that legume cover crops (subterranean clover and common vetch) increased soil organic matter and could represent an economic and sustainable soil use to reduce the amount of nitrogen fertilizers applied in table grape production. [ABSTRACT FROM AUTHOR]

Weeds can cooperate with the agroecosystem's functioning by providing ecosystem services. Effective weed management should mitigate negative weed–crop interference, while maintaining a functional and balanced weed community. In a two-year trial, the in-line/roller crimper (RC) was used to terminate an agroecological service crop (ASC; here barley, Hordeum vulgare L.) before organic zucchini (Cucurbita pepo, L.) and compared with green manure (GM) ASC and tilled no-ASC with Mater-Bi mulch on the rows (No_ASC). Zucchini yield, soil N availability, weed density/cover, biomass, and community composition were assessed. Analysis of variance, exploratory statistical analysis, and non-parametric inferential approaches were run, respectively, on agronomic data, species-specific weed frequencies, and Shannon diversity. Zucchini yield was the highest in No_ASC, due to soil N immobilization under high C:N barley residues in GM and RC. Multivariate analysis discriminated RC from tilled systems, outlining a specific ensemble of weed species correlated to Shannon diversity. From zucchini fruit set, RC selectively favored Polygonum aviculare L. and Helminthotheca echioides (L.), reasonably because of their oligotrophy and creeping habit. Their dominance finally caused low RC weed control. Results highlight strong weed selective pressure by the mulch-based no-tillage. Understanding the mechanisms underpinning the impact of soil management practices on weed community can drive towards a tailor-made and more effective weed management. [ABSTRACT FROM AUTHOR]