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Planting green manure to improve cash crop yield and soil health has been widely recognized, and understanding cash crop performance after green manure integration is pivotal for determining its potential to bolster and enhance crop productivity and sustainable production. However, it is unclear whether the effects of different types of green manure on subsequent cash crops are uniform. In order to clarify this issue, we systematically analyzed the effects of green manure types and nitrogen (N) application rates on succeeding cotton agronomic performance, yield, biomass, yield stability, and nutrient uptake. A split‐plot experiment with two factors was designed, main factor includes four cover cropping systems monoculture cotton (MC), February orchid/cotton cover cropping (FoC), hairy vetch/cotton cover cropping (HvC), and a mixture of February orchid and hairy vetch/cotton cover cropping (FHC), and sub‐main factor include four N application levels (0 (N0), 112.5 (N1), 168.75 (N2), and 225 (N3) kg N ha−1). Results suggests that nonlegume green manure (February orchid) accumulated more biomass, N, P, and K nutrients than the legume green manure (hairy vetch) and green manure mixture. Compared with cotton yield of MC, the FoC, HvC, and FHC system increased by 5.8%, 7.6%, and 15%, respectively. N use efficiency was more significantly influenced by the N application rates than by cropping systems. Specifically, as N application rates increased, N use efficiency decreased under MC, HvC, and FHC systems, while it increased under the FoC system. Additionally, we observed a trade‐off between cotton yield and yield stability, with the highest yield stability when cotton yield reached 2633 kg ha−1. This study provides evidence that nonlegume green manure (February orchid) with greater advantages on cotton vegetative organ growth, legume green manure (hairy vetch) can promote nutrient uptake compared to other green manure, while green manure mixture (February orchid and hairy vetch mixture) significantly increased cotton yield and yield stability. These findings provide evidence‐based insights highlighting the respective benefits of incorporating diverse species of green manure into cotton‐based cropping systems in the Yellow River Basin of China. [ABSTRACT FROM AUTHOR]

Intensification of crop sequence (ICS) has been proposed as a key field practice to preserve soil health and achieve more sustainable agricultural systems. However, the effects of ICS are site‐specific and vary according to soil characteristics, climatic conditions, the duration of the crop sequencing and the types of crop involved. Soil aggregate stability (AS) and soil organic carbon (SOC) stock are useful indicators of soil health as they are closely linked to diverse soil services and functions and are sensitive to management practices. We performed a meta‐analysis of 33 studies to analyse the impact of ICS on SOC stock and AS in field experiments in the central‐eastern region of Argentina. Our results showed that ICS increased SOC stock and AS, with an overall mean change of 7% and 22%, respectively. Fine‐textured soils showed the greatest SOC stock increase (12%), comparable to the increase observed in coarse‐textured soils (11%); in medium‐textured soils this increase was less than half (5%). Coarse‐textured soils had the greatest increase in AS (32%), followed by medium‐textured and fine‐textured soils, which also showed notable improvements (25% and 19%, respectively). Greater diversity of crops resulted in larger increases in both AS and SOC. ICS generated a larger increase of SOC stock in the soil surface (0–10 cm) than in the subsurface (10–20 cm), whereas the opposite was found for AS. Long‐term studies (≥9 years) had the greatest effect on AS and SOC stock. Regression analysis revealed that the initial carbon stock influenced SOC stock results following ICS, increases being greater when initial carbon stock contents were smaller. Introducing gramineous species into the crop sequence was associated with a greater improvement of AS and SOC stock. Finally, the mean rate of carbon sequestration from ICS in all the studies amounted to 0.28 Mg ha−1 yr−1. Overall, ICS is a useful strategy for improving SOC storage and AS in this region, though results may vary according to soil characteristics and management practices. [ABSTRACT FROM AUTHOR]

Two field experiments were conducted to evaluate the effect of tillage, crop residues and crop rotation on productivity of clover, maize and mung bean, at the experimental research station of the College of Agricultural Engineering Sciences - University of Baghdad in Aljadriya, Baghdad – Iraq during two seasons of 2021-2022. 1st trail was with two factors: residues (0%R and 100%R) and tillage (minimum (MT) and conventional (CT)) with four replicates. Results indicated the best values of height and dry matter yield were (70.25 cm and 5.558 Mg ha-1 ) for (100%R+MT) compared with (65.5 cm and 4.985 Mg ha-1 ) for (0%R+CT) respectively. The 2nd trail was with three factors: the same tillage and residues coupled with crop rotations (clover-maize) and (clover-mung bean). Results (representing the accumulated effect of both trials) indicated the best values of height, dry matter yield and grains and seeds yield were (236.25 and 111.5) cm, (4.560 and 14.745) Mg ha-1, (6.840 and 3.754) Mg ha-1 for (100%R+MT) treatment compared to (210.0 and 101.25) cm, (4.048 and 11.337) Mg ha-1, (5.685 and 2.829) Mg ha-1 with (0%R+CT) for maize and mung bean respectively and under crop rotations (clover-maize) for maize and (clover- mung bean) for mung bean. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at ICAR-Central Potato Research Institute-RS, Gwalior, in split-plot design: 3 irrigation methods (main plots) and 5 fertilizer doses in various crop sequences (sub-plots), with four replications. Results revealed that the highest total tuber number (604 thousand/ha) was recorded with dhaincha - potato (75% RDF NPK) which was significantly higher than all other treatments except green gram - potato (75% RDF NPK). Drip irrigation resulted in highest total tuber yield (35.8 t/ha), significantly surpassing other methods. Dhaincha - potato (75% RDF NPK) combination yielded (37.5 t/ha) highest, significantly outperforming others except fallow - potato (50% RDF NPK/ha + 15 t FYM) sequence. Drip irrigation x fallow - potato (50% RDF NPK/ha + 15 t FYM) combination recorded the highest total tuber yield at 40.3 t/ha. Drip irrigation resulted in water-use efficiency of 137 kg/ha-mm and harvest index of 72%, significantly surpassing other methods. Fallow - potato {FYM 7.5 t/ha + crop residue 7.5 t/ha + biofertilizers (Azotobacter and PSB)} sequence recorded highest harvest index 73%, significantly surpassing other treatments. Drip irrigation resulted in highest WUE (137 kg/ha-mm), significantly surpassing other methods. Combination of drip irrigation x fallow - potato (FYM 7.5 t/ha + 50% RDF NPK) sequence recorded highest WUE (155 kg tuber/ha-mm), significantly outperforming other treatments. Dhaincha - potato (75% RDF NPK) sequence resulted in the highest nitrogen content (216 kg/ha), significantly surpassing others. Dhaincha - potato (75% RDF NPK) sequence significantly out performed in tuber nitrogen uptake (77 kg/ha) to other sequences. Combination of drip irrigation x dhaincha - potato (75% RDF NPK) sequence recorded highest N uptake (83 kg/ha). Benefit: cost was highest with drip irrigation (3.1) among irrigation methods and it was highest with dhaincha - potato (75% RDF NPK) sequence (2.99) among crop sequences. [ABSTRACT FROM AUTHOR]

In dryland Mediterranean Vertisols, split nitrogen (N) application is usual in wheat crops. Because of the high clay content of these soils and the low rainfall, a single application might offer ecological and economic benefits without yield loss. We conducted a 5-year study as part of a long-term experiment and compared the split application of N (50% at tillering, 50% at stem elongation phase) with a single application (tillering) in 10 cropping systems resulting from the combination of type of cultivation (no-till and conventional tillage) and 2-year crop rotations (wheat-wheat, wheat-fallow, wheat-chickpea, wheat-faba bean and wheat-sunflower). Depending on the system × crop rotation interaction, a single application of 100 or 150 kg N ha-1 maintained grain yield, protein content and apparent N recovery, with no effect on nitrate content compared with a traditional split application. The average grain yield did not differ between split and single application of N (3.27 and 3.23 Mg ha-1, respectively, for single and split application of 100 kg N ha-1 rate; 3.46 and 3.40 Mg ha-1, respectively, for single and split application of 150 kg N ha-1 rate). The soil nitrate concentration at pre-seeding in the 0-0.3 m layer showed similar results, except in the case of the wheat-faba rotation, with lower nitrate concentration in the sub-subplots of single application and no-till. This work shows that adopting the single N application strategy in rotations on Mediterranean dryland Vertisols will reduce economic and environmental costs. [ABSTRACT FROM AUTHOR]

An experiment of integrated farming system (IFS) model comprising of 1.0 ha area was conducted during 2010-11 to 2018-19 at the Centre for Research on Integrated Farming Systems, Sardarkrushinagar, Dantiwada Agricultural University, Sardarkrushinagar of Gujarat for validation of an IFS model. There were four cropping system and allotted area was 0.70 ha, viz. castor (Ricinus communis L.) + greengram (Vigna radiate (L.) R. Wilczek] (0.32 ha); groundnut (Arachis hypogaea L.)- wheat (Triticum aestivum L.)-multicut fodder pearl millet [Pennisetum glaucum (L.) R. Br.] (0.08 ha); greengram - Indian mustard [Brassica juncea (L.) Czemj.]-pearlmillet (0.24 ha); and hybrid napier [Pennisetum purpureum (Schumach)] + fodder cowpea [Vigna unguiculata (L.) Walp.] - Lucerne (Medicago sativa L.) + fodder chicory (Cichorium intybus L.) (0.06 ha) based on small and marginal farm family requirement. N addition to that fruits and vegetable in 2 tiers were sown on 0.25 ha, making microbes-enriched vermin-compost from the waste and dung of the 2 buffaloes (Bubalus bubalis) reared on 0.04 ha. Farm wastes were recycled within the system which obliterated the need to purchase off-farm inputs. The internal bunds of cropping systems were used for growing fodder, while farm boundary with quick-growing timber tree. The model had a provision of farm pond (0.01 ha) for water harvesting and well recharging on low-lying depression of the farm. Groundnut - wheat - multicut F. Rajka Bajra + Horticultural and Vegetables crops +Live stock+ vermi compost + boundary plantation + farm pond registered significantly higher GEY (8696 kg/ha), which was statistically at par with IFS Model (Castor + Greengram (032 ha) + Groundnut - Wheat -Multicut F. Rijka Bajra (0.08 ha)+ Green gram -Mustard-Pearl millet (0.24 ha)+ Hy. Napier + Cowpea (F) - Lucerne + F. Chicory (0.06 ha)+Horticultural and Vegetables crops (0.25 ha) +Live stock(0.025 ha) + vermi compost (0.010 ha)+ boundary plantation + farm pond (0.015 ha) (7977 kg/ha) registered significantly higher employment generation (476 mandays/year). [ABSTRACT FROM AUTHOR]

Crop mapping at an earlier time within the growing season benefits agricultural management. However, crop spectral information is very limited at the early crop phenological stages, leading to difficulties for within-season crop identification. In this study, we proposed a deep learning-based fusion method for crop mapping within the growing season, which first learned a priori information (i.e., pre-season crop types) from historical crop planting data and then integrated the a priori information with the satellite-derived crop types estimated from spectral times-series data. We expect that preseason crop types provided by crop rotation patterns is an effective supplement to spectral information to generate reliable crop maps in the early growing season. We tested the proposed fusion method at three representative sites in the U.S. with different crop rotation intensities and one site with cloudy weather conditions in the Sichuan Province of China. The experimental results showed that the fusion method incorporated the strengths of pre-season crop type estimates and the spectral-based crop type estimates and thus achieved higher crop classification accuracy than the two estimates throughout the growing season. We found that pre-season crop estimates had a higher accuracy in the scenarios with either nearly continuous planting or half-time planting of the same crop. In addition, the historical crop type data strongly affected the performance of pre-season crop estimates, suggesting that high-quality historical crop planting data are particularly important for crop identification at earlier times in the growing season. Our study highlighted the great potential for near real-time crop mapping through the fusion of spectral information and crop rotation patterns. [ABSTRACT FROM AUTHOR]

Conservation agriculture helps to mitigate the adverse impacts of conventional practices and intensive cultivation, accordingly enhancing agricultural sustainability. Tillage management and the preceding crop impact the sustainable use of soil resources and ultimately crop growth and productivity. The present study aimed to assess the impacts of the tillage system, cropping system, and their different interactions on soil properties and agronomic performance. No-tillage (NT), reduced tillage (RT), and conventional tillage (CT) were combined with three cropping systems; continuous wheat (wheat/wheat/wheat, W/W/W), lentil/wheat/lentil (L/W/L), and oat/wheat/barley-pea (O/W/BP) during three years crop rotation. The results displayed that the conservative practices (NT and RT) recorded higher soil nutrient content (N, P, K, Ca, and Mg) than conventional tillage (CT). Moreover, NT and RT exhibited higher bulk density (BD) and lower water infiltration rates compared to CT. Besides, NT and RT tended to have higher soil moisture than CT. The cropping system W/W/W displayed higher magnesium content, while W/L/W had higher phosphorous and O/W/BP showed higher sodium values. The mono-cropping system under conventional tillage tended to have lower soil nutrient content compared to the other combinations. The highest wheat aboveground biomass, wheat grain yield, and lentil seed yield were produced by RT and CT compared to NT. Otherwise, the higher emergence of barley-pea was assigned for NT followed by CT and RT. [ABSTRACT FROM AUTHOR]

[Display omitted] • AgrOptim is an extensive cropping system simulation optimization framework. • Crop and environmental risk simulation models are coupled with genetic algorithms. • Management practices that optimize different biophysical and economic objectives are identified. • Trade-offs between economic and biophysical indicators are simulated and quantified. • Sustainability gaps are quantified for three cropping systems in Argentina. Cropping systems should be designed to be more productive and have a smaller environmental footprint to sustainably meet the growing demand for food, fiber, and fuel. However, this requires the evaluation and ranking of many cropping system designs based on their economic and biophysical performance, which are often in conflict. Although field experiments and simple crop simulation models have been used for this purpose, studies have generally considered a limited number of agronomic decision combinations or indicators that partially capture ecosystem functions. Coupling evolutionary algorithms with process-based crop simulation models provides a less resource-intensive alternative and can incorporate many indicators to (1) quantify the trade-offs between biophysical and economic performance, and (2) identify the set of agronomic decision combinations that minimize these trade-offs. The objective of this paper was to present AgrOptim, a novel cropping system simulation optimization framework that uses genetic algorithms to optimize a holistic set of biophysical and economic performance indicators through different combinations of agronomic decision variables (i.e., crop sequence, crop structure, pesticide dose, and fertilizer dose). Indicators were derived from a process-based crop simulation model, an ecotoxicological risk simulation model, and emergy synthesis. The framework was implemented in Argentina to (1) characterize the relationship between economic and biophysical indicators and (2) evaluate the current state and potential improvements of three frequently used cropping system designs. A multi-objective optimization experiment was designed to simultaneously optimize 30-year cropping sequences based on one economic objective (return on investment) and four biophysical objectives (crop residue carbon inputs, precipitation use efficiency, nonrenewable to renewable energy ratio, and pesticide ecotoxicity). Results showed that trade-offs exist between economic and all biophysical objectives, albeit with varying intensities. Additionally, the decision variables that provided improved performance in terms of carbon residues, precipitation use efficiency, and ecotoxicological risk also presented higher levels of nonrenewable energy use. For the three frequently used cropping system designs, the decision variables that improved the performance of each indicator were identified. These findings highlight the challenges faced by agricultural producers considering the trade-offs between their economic and biophysical objectives. Additionally, they reveal potential model-aided improvements that can be obtained using crop simulation models and optimization algorithms to redesign cropping systems. [ABSTRACT FROM AUTHOR]

Biofumigant and crop sequencing are effective and safe control system activators that maintain soil fertility and reduce pest populations. The study goals were to find new pesticide-free therapies for root-knot nematode management on cucumbers to maintain high yields and protect the environment and human health. In 2018 and 2019, the research employed a fully randomized block design under field conditions with five treatments and control: two bio- fumigants, cultivation of cucumber after broccoli plantlets incorporation (BPI) and radish plantlets incorporation (RPI), two crop sequence treatments (cultivation after broccoli (BCS) and radish (RCS), and nematicide treatment). Cucumber cultivation after BPI treatment exhibited the best horticultural traits, which reflected positively on early and total productivity. The increased yield was gained by suppressing all nematode parameters, the number of nematode larvae, galls, and egg masses, as well as egg hatching reduction. The most effective biocides, total phenols, myrosinase activity, total glucosinolates (GSLs), and isothiocyanates (ITCs) in brassica crops were estimated for their pesticide properties. The highest amount was released with BPI treatment, compared to adult plants and radish in its two stages. The bio-managed treatments revealed superior effectiveness compared to nematicide application and control to suppress the nematode population while enhancing cucumber growth and production. [ABSTRACT FROM AUTHOR]

The current understanding of the link between land management practices and GHG (greenhouse gas) emissions is limited in the small-scale farm sector of sub-Sahara regions due to insufficient or fragmented land-use data. Land-use categories recognized in the national GHG inventories in Kenya are coarse. Therefore, they do not adequately account for the diversity in small-scale land uses. Characterization of land-use and knowledge of key drivers of land-use change is necessary to improve national GHG inventories in the SSA (Sub-Sahara Africa) region. We implemented a cross-sectional survey to characterize land-use and determine factors which influenced changes in land use within small-scale farms of Tharaka-Nithi County, Kenya. We sampled 300 farmers using multistage sampling and collected crop sequence recall data at plot level for three years (seven seasons). We grouped crop sequences into clusters using the ‘TraMineR’ R package. We derived four clusters including banana, tea, and declining fallows (cluster 1, 19.2% of plots), cereal-legume systems (cluster 2, 55.1%), fodder (cluster 3, 11.7%) and coffee (cluster 4, 14.0%). We observed higher N application rates in perennial cropping systems, than in annual crops, including cereal-legume systems. We observed that farmers in higher potential agro-ecological zones, male-managed farms, with higher per capita land area, higher remittances and higher total house-hold incomes, were associated with a higher propensity to adjust crop enterprises, leading to more unstable land-use sequences. Contrariwise, farmers with higher education, credit access, secure land tenure, increasing slope, good soil fertility, and longer farming experiences recorded a lower propensity to adjust their land uses, resulting in more stable crop sequences. Farmer socio-demographic characteristics influenced land-use change, which is directly linked with soil GHG emissions. Our findings propose the adoption of Tier II GHG quantification approaches which disaggregate between annual and perennial crop enterprises. GHG emissions are likely to be more generalizable in stable perennial crop systems than annual systems. Thus, better disaggregation of GHG sampling in annual crop systems is needed due to high diversity in crop and soil fertility management, and the dynamic nature of C and N cycling in these systems.

Crop rotation and soil tillage are among key factors impacting cropping system productivity, pest management and soil health. To assess their role in northern cropping systems, we quantified the effects of crop rotation on spring wheat yield in different tillage systems based on a long-term (2005–2017) field experiment in southwestern Finland. In addition, effects of crop rotation on weeds, plant pathogens, and pest insects were assessed. Three types of crop rotation were compared: monoculture (spring wheat), 2-year rotation (spring wheat—turnip rape—spring wheat—barley) and 4-year rotation (spring wheat—turnip rape—barley—pea) under no-tillage and plowing. A diversified crop rotation improved spring wheat yield by up to 30% in no-tillage and by 13% under plowing compared with monoculture. Overall, the yield quantity and quality differences between crop rotations were higher in no-tillage plots than in plowed plots. The occurrence of weed species in spring wheat before herbicide control was highest in the four-year crop rotation and lowest in the wheat monoculture. For plant diseases, wheat leaf blotch disease severity, mainly caused by Pyrenophora tritici-repentis, was lowest in the most diverse crop rotation. On average, wheat leaf blotch disease severity was 20% less when wheat was grown every fourth year compared with wheat monoculture. The effect of crop rotation on stem and root diseases became apparent after 6 years of rotation and the disease index was lowest in the most diverse crop rotation. Neither rotation nor tillage affected the control need of wheat midge (Sitodiplosis mosellana). Based on our results, diverse crop rotations including cereals, oilseed crops, and legumes increase yield and reduce plant disease severity of spring wheat in Finland, with the magnitude being larger in no-tillage systems.

Diversifying cropping systems by increasing the number of cash and cover crops in crop rotation plays an important role in improving resource use efficiency and in promoting synergy between ecosystem processes. The objective of this study was to understand how the combination of crop diversification practices influences the performance of arable crop sequences in terms of crop grain yield, crop and weed biomass, and nitrogen acquisition in a temperate climate. Two field experiments were carried out. The first was a 3-year crop sequence with cereal or grain legume as the first crops, with and without undersown forage legumes and forage legume-grass crops, followed by a cereal crop. The second experiment was a 2-year crop sequence with cereal or legume as the first crops, a legume cover crop, and a subsequent cereal crop. For the first time, crop diversification practices were combined to identify plant-plant interactions in spatial and temporal scales. The results partly confirm the positive effect of diversifying cereal-based cropping systems by including grain legumes and cover crops in the crop sequence. Legume cover crops had a positive effect on subsequent cereal grain yield in one of the experiments. Using faba beans as the first crop in the crop sequence had both a positive and no effect on crop biomass and N acquisition of the subsequent cereal. In cover crops composed of a forage legume-grass mixture, the grass biomass and N acquisition were consistently increased after the grain legume, compared to the cereal-preceding crop. However, differences in the proportion of legume to grass in mixture did not influence crop yield or N acquisition in the subsequent cereal. In conclusion, these results support that increased crop diversity across spatial and temporal scales can contribute to resource-efficient production and enhance the delivery of services, contributing to more sustainable cropping systems. [ABSTRACT FROM AUTHOR]

Purpose: Precrops exhibit vigorous deep root growth, especially when grown perennially. However, their contribution to accumulate essential nutrients derived from deeper soil layers in the topsoil has not been quantified. We determined the vertical distribution of phosphorous (P) and potassium (K) affected by contrasting root systems of 3 precrops and their effects on subsequently grown spring wheat. Methods: Three precrops (lucerne, chicory and tall fescue) were grown for 1, 2 and 3 years prior to spring wheat cultivation. We measured plant available soil P and K from 0 to 30 cm to 75–105 cm of soil depth after precropping. Root growth and crop performance of spring wheat as affected by precropping were measured in two repeated trials. Results: We observed maximum 22-fold higher root-length density (RLD; cm cm− 3) of taprooted chicory compared with fibrous-rooted tall fescue in the subsoil. There were significant increases in plant available K in the topsoil by 27 mg kg− 1 over the precrop duration between 1 and 3 years. Grain yield of subsequently grown spring wheat was significantly increased by 10 % and 14 % from 1 year to 3 year-treatments of lucerne and chicory, respectively. Similarly, significant increases in P uptake (7 % and 19 %) and K uptake (21 and 14 %) of spring wheat was noted for the same treatments. Conclusions: Our data suggest that there is potential for the yield of short-season cereals to be improved by increased soil nutrient bioavailability in the topsoil derived from deeper soil layers by the deep roots of perennial precrops. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine the impact of plant diversity and agricultural practices on crop productivity on organically managed mixed and arable farms under different natural conditions. Organic farms in three regions of Lithuania, differing in landscape homogeneity, soil quality and farming intensity, were evaluated. The results showed that there were arable farms in all regions, regardless of the soil fertility and the largest number of mixed farms was in Western Lithuania. On the mixed farms, perennial forage grass prevailed in the cropping structure, whilst cereals were the main crops on the arable farms with grain legumes grown to restore soil fertility. Short crop rotations and a low diversity of crops predominated. The average grain yields of the winter and spring cereals and the grain legumes were 3283, 2539 and 2917 kg ha−1, respectively. The productivity of the cereals and grain legumes depended on the region, and for spring cereals also on the interaction between region and farm type. Significantly lower yields of winter and spring cereals were recorded on the arable farms in East Lithuania, compared with the arable farms in the other regions. For organic farming systems, especially for arable farms, it was recommended to explore and implement the use of mixed or strip relay intercrops and multicultural cropping systems or blocks, thereby increasing spatial and temporal crop diversity and using plants that provide ecological services (e.g. legume swards). Reduced tillage practice to increase humification of plant residues in the soil was also recommended. [ABSTRACT FROM AUTHOR]

Biofumigant and crop sequencing are effective and safe control system activators that maintain soil fertility and reduce pest populations. The study goals were to find new pesticide-free therapies for root-knot nematode management on cucumbers to maintain high yields and protect the environment and human health. In 2018 and 2019, the research employed a fully randomized block design under field conditions with five treatments and control: two bio- fumigants, cultivation of cucumber after broccoli plantlets incorporation (BPI) and radish plantlets incorporation (RPI), two crop sequence treatments (cultivation after broccoli (BCS) and radish (RCS), and nematicide treatment). Cucumber cultivation after BPI treatment exhibited the best horticultural traits, which reflected positively on early and total productivity. The increased yield was gained by suppressing all nematode parameters, the number of nematode larvae, galls, and egg masses, as well as egg hatching reduction. The most effective biocides, total phenols, myrosinase activity, total glucosinolates (GSLs), and isothiocyanates (ITCs) in brassica crops were estimated for their pesticide properties. The highest amount was released with BPI treatment, compared to adult plants and radish in its two stages. The bio-managed treatments revealed superior effectiveness compared to nematicide application and control to suppress the nematode population while enhancing cucumber growth and production.

The microbial composition of the rhizosphere soil could be an important determinant of crop yield, pathogen resistance, and other beneficial attributes in plants. However, little is known about the impact of cropping sequences on microbial community dynamics, especially in economically important species like soybean. Using 2-year crop sequences of corn-soybean, canola-soybean, and soybean-soybean, we investigated how crops from the previous growing season influenced the structure of the microbiome in both the bulk soil and soybean rhizosphere. A combination of marker-based Illumina sequencing and bioinformatics analyses was used to show that bacterial species richness and evenness in the soybean rhizosphere soil were similar following canola and soybean compared to a previous corn sequence. However, fungal species richness and evenness remained unaffected by crop sequence. In addition, bacterial and fungal species diversity in both the bulk and soybean rhizosphere soil were not influenced by crop sequence. Lastly, the corn-soybean sequence significantly differed in the relative abundance of certain bacterial and fungal classes in both the soybean rhizosphere and bulk soil. While canola-soybean and a continuous soybean sequence did not, suggesting that a preceding corn sequence may reduce the occurrence of overall bacterial and fungal community members. For the present study, crop sequence impacts bacterial diversity and richness in both the bulk soil and soybean rhizosphere soil whereas fungal diversity and richness are resilient to crop sequence practices. Together, these findings could help drive decision making for annual crop and soil management practices.

The microbial composition of the rhizosphere soil could be an important determinant of crop yield, pathogen resistance, and other beneficial attributes in plants. However, little is known about the impact of cropping sequences on microbial community dynamics, especially in economically important species like soybean. Using 2-year crop sequences of corn-soybean, canola-soybean, and soybean-soybean, we investigated how crops from the previous growing season influenced the structure of the microbiome in both the bulk soil and soybean rhizosphere. A combination of marker-based Illumina sequencing and bioinformatics analyses was used to show that bacterial species richness and evenness in the soybean rhizosphere soil were similar following canola and soybean compared to a previous corn sequence. However, fungal species richness and evenness remained unaffected by crop sequence. In addition, bacterial and fungal species diversity in both the bulk and soybean rhizosphere soil were not influenced by crop sequence. Lastly, the corn-soybean sequence significantly differed in the relative abundance of certain bacterial and fungal classes in both the soybean rhizosphere and bulk soil. While canola-soybean and a continuous soybean sequence did not, suggesting that a preceding corn sequence may reduce the occurrence of overall bacterial and fungal community members. For the present study, crop sequence impacts bacterial diversity and richness in both the bulk soil and soybean rhizosphere soil whereas fungal diversity and richness are resilient to crop sequence practices. Together, these findings could help drive decision making for annual crop and soil management practices. [ABSTRACT FROM AUTHOR]

The current context of food security and global geopolitical crises calls for proactive efforts to seek adaptive strategies for limited resources in agriculture. The production of phosphatic-based fertilisers has caused a substantial depletion of natural phosphorus (P) reserves, raising concerns about price increases due to the growing demand for P. The aim of the study is to assess whether the use of liquid organo-mineral P-complexes can be an adaptive strategy to address the issue of the limited P-fertiliser resource. A complete randomised block design was implemented with three replicates, spanning two contrasting cropping seasons under a Mediterranean climate with reduced tillage and rainfed conditions. The study aimed to assess the response of a durum wheat–maize rotation to various rates of liquid organo-mineral P-complexes (humic-complexed phosphate; HCP) in comparison to granular triple superphosphate (TSP). The evaluation focused on several parameters, including P availability, plant architecture, dry matter accumulation, grain yield and yield components and P use efficiency (PUE) for both durum wheat and maize. The results revealed that applying HCP at a rate of 4 or 8 kg ha−1 increased soil P availability on average by 66% and 144%, respectively, compared to the control (no P-fertilisation), although a significant interaction with the monitoring year emerged. For wheat, applying HCP at a rate of 8 kg ha−1 of P resulted in higher grain yield (+15%), protein content (+0.9%) and P uptake (+48%) than the control on average considering both monitoring years. In the season characterised by favourable rainfall patterns, the application of HCP at 5 or 10 kg ha−1 of P for maize showed similar effects in terms of soil P availability, dry matter accumulation, grain yields and PUE. Conversely, in the season marked by a deficiency in summer precipitation, low PUE for maize was observed for HCP fertilisers, although they remained positive, unlike the case of TSP. Using HCP in conservation agriculture appears promising as an adaptive solution to address P-fertiliser scarcity, especially amid food security challenges and global crises. However, further studies are required to validate these findings in diverse pedo-climatic contexts and cropping systems. • Humic complexed P fertiliser (HCP) enhances soil P availability, especially at 0–10 cm depth. • HCP resulted in a general higher maize and wheat grain yield and crops P efficiency. • HCP is promising in the context of conservation agriculture. [ABSTRACT FROM AUTHOR]

Intermediate wheatgrass (IWG) may benefit soil fertility in crop rotations. To investigate termination strategies, i.e., autumn ploughing (AP), autumn harrowing (AH) and spring harrowing (SH) on a five-year-old IWG stand, a pilot study was performed. After the treatments, beetroots were sown and the IWG plants were counted twice during the beetroot growing season. The number of IWG plants was highest (20) after the SH strategy, intermediate (14) after the AH, and lowest (3) after the conventional termination strategy, AP. After the first plant count, the plots were subject to mechanical weeding in the form of a stale seedbed (i.e., harrowing twice before sowing). At beetroot harvest, the number of IWG plants was low (3 in SH and AH, 0 in AP) and similar between the treatments. The beetroot production was highest after AP and lowest in SH, and intermediary in AH, which showed no difference from AP and SH. At beetroot harvest, the weed biomass did not differ between the termination strategies. The weeds were mainly annuals. There were no differences in soil bulk density between termination strategies. Our results show that shallow soil tillage is enough to terminate IWG, as long as it repeated. We suggest further studies that investigate the dynamics of crop sequences with IWG, and how to benefit from this crop in rotations.

The study aimed to evaluate the yield and economic effectiveness of spring barley grown in cro rotation and cereal monoculture under three tillage systems. The experimental factors were cro sequence systems: 1) crop rotation (peas -- spring barley -- winter wheat) and 2) cereal monocultu (spring barley -- winter wheat -- winter wheat) and tillage systems: a) conventional tillage (CT), reduced tillage (RT), and 3) herbicide tillage (HT). Spring barley grain yield was signifcantly higher crop rotation than in cereal monoculture. Also, yield was signifcantly higher under RT than under C and HT. The number of weeds per m-2 in cereal monoculture was significantly higher than in crop rotation. Also, more weeds occurred under RT than under CT and HT. Air-dry weight of weeds w higher in cereal monoculture than in crop rotation and it was also higher under RT than under C In crop rotation, for each tillage system the production value (EUR ha-1) was higher than in monocultur whereas the highest production value (EUR ha-1) was achieved in crop rotation in RT sites. The econom analysis showed a clear competitive advantage of RT sites with crop rotation over other sites. The pro is the highest gross margin and income from activity, and the lowest unit cost of production. Keywords: yield, crop sequence, tillage system, economic results, gross margin [ABSTRACT FROM AUTHOR]

Field experiments were conducted to develop the suitable organic farming package for rice-blackgram crop sequence during samba seasons of 2016 and 2017 at farmers' holdings in Thirupparankundram block of Madurai district, Tamil Nadu. The organic manure combinations were evaluated for their growth parameters. viz., plant height, no of tillers, no of leaves per hill, root length, root volume, root dry weight and dry matter production at various stages of the crop growth. During both the seasons of study application of green manure @ 6.25 t ha-1+split application of vermicompost @ 4t ha-1 in four equal splits (basal, AT,PI & F) + Panchagavya @ 3% as foliar spray twice (AT & PI) significantly recorded more number of tillers and highest plant height, dry matter production, root length, root volume, root dry weight, grain and straw yield over rest of the treatments. The recommended practice also recorded relatively, more number of tillers, leaves hill-1, higher plant height, dry matter production, root length, root volume, root dry weight, grain and straw yield which is on par with the aforesaid treatment. Therefore the application of green manure @ 6.25 t ha-1+split application of vermicompost @ 4t ha-1 in four equal splits (basal, AT,PI & F) + Panchagavya @ 3% as foliar spray twice (AT & PI) can be recommended for adoption in organic cultivation of riceblack gram crop sequence grown organically. [ABSTRACT FROM AUTHOR]

Increasing dryland cropping intensity by integrating cover crops into crop-fallow rotations can add diversity and alter soil ecosystem functions, including improvements in soil nutrient and water retention and cycling, and suppression of soil-borne pests. However, the use of cover crops can also carry the risk of increasing the abundance of plant-parasitic nematodes that could undermine system productivity. Here, we examined how the integration of diverse cover crops of different functional groups: Poaceae [forage oat (Avena sativa L.)]; Brassicaceae [forage rape (Brassica napus L.)]; and Fabaceae [common vetch (Vicia sativa subsp. sativa L. and fababean (Vicia faba L.) in monocultures and mixtures into a dryland crop-fallow rotation altered soil nematode community composition and structure relative to conventional fallows. We found that cover crop mixtures had greater diversity and complexity of free-living nematodes, indicating enhanced cycling of energy and nutrients (enrichment index >50 %) compared to monocultures. Furthermore, using a structural equation modelling approach, we showed the abundance of free-living nematodes is driven primarily by cover crop residue quality (C:N ratio, and cellulose content) and marginally by cover crop quantity (biomass). The grass-legume mixture had the highest abundance of plant-parasitic nematodes (Pratylenchus neglectus and Merlinius brevidens) but also fostered robust soil food webs with complex soil nematode trophic interactions, indicating promotion of soil ecosystem functions related to N and C cycling and overall improvement in soil health. The results indicate bottom-up effects of cover crops on soil nematode communities are modulated by cover crop functional type and mixture composition. Consequently, cover crops with appropriate traits must be selected if soil health is to be improved via suppression of plant-parasitic nematodes, promotion of free-living nematodes, and enhancement of soil food web complexity. • Cover cropping can improve soil nematode community diversity. • Cover crop effects on soil nematodes are modulated by cover crop functional type. • Grass-legume mixture had high abundance of Pratylenchus neglectus and Merlinius brevidens. • Cover crop C/N and N concentration fostered robust soil food web conditions. [ABSTRACT FROM AUTHOR]

A field experiment was conducted at Regional Station, Bathinda during 2010-2013 to evaluate various crop sequences under variable irrigation regimes. The experiment was conducted in split plot design with six crop sequences, viz. barley-Bt cotton, barley-cluster bean, barley-green gram,mustard-Bt cotton, mustard-cluster bean and mustardgreen gram in main plots and three irrigation regimes [optimum (O), sub-optimum (SO) and sub-sub optimum (SSO) ] were kept in sub plots with three replications. The grain yield of barley reduced significantly where grown after cotton to the tune of 10.8 and 9.2% as compared to green gram and cluster bean, respectively. The barley grain equivalent yield (BGEY) was higher in mustard under all the preceding crops (cotton, green gram and cluster bean).Significant increase in cotton equivalent yield (CEY) was noticed in cotton sown after barley than mustard. Amongst the CEY of the system, barley-cotton crop sequence gave significantly highest CEY which was at par with mustard-clusterbean and mustard-cotton crop sequence. Significantly higher barley grain yield, mustard grain yield and cotton equivalent yield was recorded in optimum water regime, followed by SO and lowest in SSO regime. Water expense efficiency (WEE) of barley was higher preceding greengram followed by cluster bean and lowest in cotton system. Whereas, WEE was almost same under mustard succeeding cotton and greengram but was lowest in mustard-cluster bean crop sequence. The maximum water productivity (WP) was recorded in clusterbean- mustard followed by clusterbeanbarley crop sequence. The sub-sub-optimum irrigation regime recorded highest WP followed by SO and lowest in optimum. The highest organic carbon was observed under cluster bean-barley followed by cluster bean-mustard cropping system. The potassium content deceased in cotton based crop sequence as compared to cluster bean and greengram crop sequence. Whereas, increase in available N, and P was noticed in cluster bean and green gram based cropping systems than cotton based sequence. The highest cost of cultivation was recorded in cotton based cropping sequences and lowest in cluster bean based cropping sequences. Consequently, higher net returns, B: C ratio were obtained in clusterbean based crop sequence than cotton based sequence.The optimum water regime showed highest gross returns, net returns and benefit cost ratio.

Highlights • This study reviews the results of global oilseed rape crop rotation experiments. • There is a worldwide trend to grow oilseed rape in shorter crop rotations. • Growing oilseed rape in short rotations resulted in yield losses across the major production areas. • High frequency oilseed rape cropping is related to increased disease levels, infestation with pests and high weed pressure. • There is an urgent need of diversified crop rotations for a sustainable oilseed rape production. Abstract Over the past decades, the economic benefit has prompted farmers to grow oilseed rape (OSR). Consequently, the global OSR production increased considerably, and today the crop is grown in shorter rotations than ever before. This development is evident for the major growing regions in the European Union, Canada, China, India and Australia. OSR crops usually yield more if grown after other species than when grown after OSR. Based on >550 comparisons, this review quantifies the yield benefit of OSR growing after a break crop with OSR after OSR as well as OSR growing after two-year and three-year breaks with continuous OSR. The mean yield increase varied with species of break crop and crop break intervals, ranging from 0.22 t ha−1 for OSR after barley to 0.46 t ha−1 after legumes, with a ranking of: barley < wheat < legumes. The mean yield increase of OSR after barley was consistent over varying yield levels of the following OSR, while it was inconsistent for OSR following wheat and legumes, with a lower yield response of OSR after wheat and a higher yield response of OSR after legumes at high yield levels. The mean additional yield after two successive break crops was 0.53 t ha-1, but depended on the yield of the following OSR crop and decreased at higher yield levels. A three-year break demonstrated a consistent yield benefit of 0.47 t ha-1 independent of the yield level of the succeeding OSR crop. We discuss the underlying mechanisms how different break crops and break intervals affect the seed yield of OSR, with a particular focus on diseases, pests and weeds. By quantifying the effects of different break crops and break intervals, it is our aim to provide the basis for decision to grow OSR in diverse rotations, to maintain the resources which contributed to the success of the OSR crop over the past decades, to exploit the full yield potential of the crop and to promote more sustainable OSR cropping systems. [ABSTRACT FROM AUTHOR]

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Industrial inputs have replaced crop rotations for fertility and pest management in input-intensive agriculture, resulting in a high number of crop sequence permutations and negative impacts on ecosystems and human health. Strengthening diversified and agronomically optimised crop sequences is critical to promoting sustainable practices. Comprehensive crop sequence diagnosis methods play an important role in evaluating and improving current crop sequence practices. However, recent literature has focused on annual crops, leading to biased results in crop sequence analysis for organic farming and livestock regions, where multiannual temporary fodder crops are a key aspect of crop sequences. This paper extends two methods of crop sequence analysis by including multiannual temporary fodder crops. By applying these generalised methods to a case study in the beef grassland regions of Belgium, using IACS crop data from 2015 to 2020, we reveal significant differences in the agronomic quality of the crop sequences across the territory and between organic and non-organic fields. In contrast to the existing literature, the inclusion of multiannual temporary fodder crops highlights the prevalence of high diversity and high agronomic quality sequences in livestock farming regions. Maize monoculture (of low agronomic quality), temporary grasslands (associated with high quality crop sequences) and organic certification are the main drivers of crop sequence quality in the regions studied. • We used IACS crop data to assess crop sequences in grassland regions. • Farmers do not follow cyclic crop rotations. • Grassland regions show a high share of crop sequences of high agronomic quality. • Multiannual temporary crops play a key role in crop sequence agronomic quality. • Crop sequences certified organic have higher diversity and agronomic quality. [ABSTRACT FROM AUTHOR]

Farming systems in tropical regions of the world have been shown to be underperforming. [...]

Field experiments show that wheat grown after oilseed rape (OSR) achieves higher yield levels, while the nitrogen (N) application is reduced. However, field experiment data are based on few locations with optimised management. We analysed a large dataset based on farm data to assess the true extent of break crop benefits (BCB) for yield and N fertilisation within German commercial farming. Across all German states and years, average yield of wheat preceded by OSR was 0.56 Mg ha-1 higher than yield of wheat preceded by cereals (7.09 Mg ha-1), although considerable variation between regions was observed. Mean N application across all states to wheat after OSR was 5 kg ha-1 lower than towheat after cereals. Choice of wheat types for different end uses (bread flour or animal feed) showed higher (0.77 Mg ha-1) or lower (0.44 Mg ha-1) BCB for yield of wheat cultivated after OSR compared with after cereals. The calculated BCB for yield and N fertilisation were lower than expected from dedicated field experiments and fertiliser recommendations. Thus the advantages of OSR as a preceding crop are generally utilised by commercial farmers in Germany but there is room for improvement. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the physical properties of soil under different tillage systems and crop sequences in an Áquic Argiudoll of Corrientes, to obtain quality indicators. The design was a completely randomized plots in factorial arrangement (3x4), where the factors were: • Tillage system, with three levels: conventional (LC), reduced (LR) and no tillage (SD); • Crop sequences with four levels: corn-oats (M-Av), corn-fallow (M-D), cotton-oats (A-Av) and cotton-fallow (A-D). The treatments were 12, with 4 replicates and 48 experimental units. In the corn and cotton seeding of the fourth production cycle, bulk density (BD), aggregate stability (AS), Infiltration (In) and mechanical resistance to penetration (MRP) were determined under field capacity conditions (CC). Variance analysis was applied with Duncan test. The MRP was higher in SD (0.27 MPa) on the surface than LR and LC (0.18 MPa), while at 7-20 cm this trend was opposite, 0.9 MPa in SD and 1.17 MPa in LC (a = 0, 05). The AE was 68.3% in SD; 54.8% in LR and 49.5% in LC (a = 0.05). It also increased infiltration under SD (2.9 cm h-1), followed by LR and LC (a = 0.05). The soil attributes could indicate soil quality would be: a) The MRP decreased by tilling soil surface with LC and LR, but presented the best conditions under SD in depth b) The rotations that ended with cotton had lower MRP (7-20 cm) than with maize crops; c) AS and In presented the highest values in SD. The practices that favored the AS collaborated to a greater In and would imply a less runoff and water erosion; d) SD presented the most favorable variations to maintain soil quality. [ABSTRACT FROM AUTHOR]

Agricultural intensification, besides increasing land productivity, also affects weed communities. We studied weed shifts in cropping sequences differing in the identity and number of crops grown. We also evaluated whether dissimilar weed communities in different cropping systems converge towards more similar communities, when the same sequence is cropped during 2 years. In three locations in the Rolling Pampa, Argentina, field experiments were conducted including five cropping systems in the first year (winter cereal/soyabean, field pea/soyabean, and field pea/maize double crops, and maize and soyabean as single crops), while the same sequence was grown in the following 2 years (wheat/soyabean double crop and maize). Changes in weed community composition and structure were analysed through multivariate analyses and frequency-species ranking plots. Weed communities differed first among sites, while weed shifts within each site were mainly associated with growing season and crop type. Differences among crop sequences were higher in the first year, mostly related to specific crop grown, rather than to the number of crops in the sequences. Differences were reduced when the same sequence was grown during two consecutive seasons. Frequency of highly common weeds was negatively associated with the number of days with high crop cover. Our findings contribute to understand weed shifts in consecutive growing seasons, which may help readapting crop sequences to reduce the occurrence of abundant weed species. [ABSTRACT FROM AUTHOR]

Soil compaction directly interferes on crop yield. The objectives of this work were to evaluate the effect of previous cultivation with palisade grass [Urochloa brizantha (C. Hochstetter ex A. Rich.) R. Webster cv. Marandu] and the use of soil correctives on the growth and yield of soybeans (Glycine max L.) cultivated under various soil compaction levels, in greenhouse conditions. The experiment was conducted in pots (columns) of 0.2 m diameter PVC tubes, composed of two rings: the lower ring, 0.4 m in height, received the soil (dystrophic Red Latosol, clayey texture) without corrective and a density of 1.0 Mg m-3; and the upper ring, 0,2 m in height, received the treatments of soil correctives and density. The experimental design was fully randomized in a 4 x 6 x 2 factorial outline, being four soil density levels (1.0; 1.20; 1.40 and 1.60 Mg m-3), six soil correctives (without corrective, lime, calcium silicate, gypsum, lime + gypsum and calcium silicate + gypsum) and two cultivation systems of the soybean (with and without previous cultivation of palisade grass). Starting from 1.2 Mg m-3 of soil density the soybean growth and yield were decreased. The use of soil correctives and previous soil cultivation with palisade grass decreased the harmful effects of the soil compaction on the soybean growth and yield. For the treatments that received previous cultivation with palisade grass, the soybean growth and yield were higher with application of lime + gypsum and calcium silicate + gypsum.A compactação do solo interfere diretamente sobre a produção das culturas. Neste trabalho, objetivou-se avaliar o efeito do cultivo prévio do braquiarão e o uso de corretivos do solo sobre o crescimento e produção da soja cultivada sob solo com vários níveis de compactação, em condições de casa de vegetação. O experimento foi conduzido em vasos (colunas) de tubos de PVC de 0,2 m de diâmetro, compostos por dois anéis: o anel inferior, de 0,4 m de altura, recebeu o solo (Latossolo Vermelho distrófico de textura argilosa) sem corretivo e densidade de 1,0 Mg m-3; e o anel superior, com 0,2 m de altura, recebeu os tratamentos de corretivos do solo (sem correção, calcário, silicato de cálcio, gesso, calcário + gesso e silicato de cálcio + gesso) e de compactação (1,0; 1,20; 1,40 e 1,60 Mg m-3 de densidade) do solo. O delineamento experimental foi inteiramente casualizado em esquema fatorial 4 x 6 x 2, sendo quatro densidades de solo, seis corretivos de solo e dois sistemas de cultivo da soja, com e sem cultivo prévio do braquiarão. A partir de 1,2 Mg m-3 de densidade de solo, foi observada redução no crescimento e produção de grãos da soja. O uso de corretivos e o cultivo prévio do solo com braquiarão amenizam os efeitos deletérios da compactação do solo sobre o crescimento e produção da soja. Para os tratamentos que receberam cultivo prévio de braquiarão, a mistura de calcário + gesso e silicato de cálcio + gesso foram os corretivos que proporcionaram maior crescimento e produção da soja.

Soil tillage and crop rotation are considered important tools in wheat leaf disease control; however, the results of investigations are inconsistent. The aim of the present study was to determine the effect of the soil tillage system and cropping sequence on the development of winter wheat leaf diseases in 2012–2017. The disease development was assessed in a two-factor experiment: (a) soil tillage system; and (b) crop rotation. Foliar fungicides were used uniformly in all variants. The results showed that tan spot (caused by Pyrenophora tritici-repentis) dominated in 2012, 2013, and 2016, but the level of Septoria tritici blotch (Zymoseptoria tritici) was essentially lower and exceeded the severity of tan spot only in 2015. The agronomic practice used significantly influenced only the development of tan spot. Reduced soil tillage and continuous wheat sowing substantially increased tan spot severity, especially when both practices were used simultaneously. Short crop rotation (only wheat and oilseed rape) provided sufficient control of tan spot in ploughed fields, whereas in non-ploughed fields, the level of this disease did not decrease. The results could be explained by differences in the pathogens’ life cycle: P. tritici-repentis ascospores in wheat debris is the main source of infection; in contrast, Z. tritici spreads by conidia from living plants.

O aumento da biomassa vegetal subterrânea e da estabilidade dos agregados do solo pelo seu manejo adequado aumentam sua capacidade para infiltrar água da chuva e resistir à erosão hídrica. Baseado nesta premissa, foi realizado um estudo de erosão em campo, sob chuva simulada, na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul - EEA/UFRGS, em Eldorado do Sul (RS), no verão de 2003/2004, utilizando um experimento de manejo do solo com 7,5 anos de duração. O objetivo da pesquisa foi investigar relações entre variáveis de manejo e de erosão, relacionadas à história de uso e manejo do solo e suas condições físicas superficiais momentâneas, criadas por tratamentos de seu preparo e de cobertura por resíduo cultural, os quais foram aplicados imediatamente antes da realização de testes de erosão com chuva simulada. Utilizou-se um Argissolo Vermelho distrófico típico, com textura superficial franco-argilo-arenosa e declividade média de 0,115 m m-1. Foram estudadas quatro seqüências culturais, com ou sem preparo (gradagem) e cobertura (resíduo cultural) do solo. Realizaram-se três testes de erosão com chuva simulada, cada um na intensidade de 64 mm h-1 e duração de 1,5 h, usando o aparelho simulador de braços rotativos. Avaliaram-se a massa de raízes mortas das plantas, o diâmetro médio ponderado de agregados do solo, a taxa constante de infiltração de água no solo e a perda total de água e de solo por erosão. A infiltração de água no solo foi maior e, inversamente, a perda de água menor no solo recém-mobilizado (superfície solta e rugosa) do que no solo não-mobilizado (superfície firme e praticamente lisa), mesmo o primeiro estando descoberto e o segundo tanto coberto quanto descoberto, com diferenças entre as seqüências culturais. No solo não-mobilizado e coberto, a perda foi pequena em todas as seqüências culturais, enquanto no solo descoberto, tanto não-mobilizado quanto recém-mobilizado, ela foi pequena somente naquelas seqüências culturais que propiciaram altos valores de massa de raízes mortas das plantas e de diâmetro médio ponderado de agregados do solo. No solo recém-mobilizado e descoberto, a diminuição da perda de solo também se deveu à rugosidade superficial criada pelo preparo. As relações da perda total de água e da perda total de solo, com a massa de raízes mortas das plantas e com o diâmetro médio ponderado de agregados do solo, foram significativas a 5 %.Increasing underground plant biomass and soil aggregate stability by application of adequate management practices enhances the quality in terms of water infiltration and erosion resistance. Based on this premise, an erosion study using simulated rainfall was carried out in the field, at an experimental station of the Universidade Federal do Rio Grande do Sul - EEA/UFRGS), in Eldorado do Sul, Rio Grande do Sul State, Brazil, in the summer of 2003/2004, in a 7.5 year soil management experiment. The purpose of the research was to investigate relationships between management and erosion variables, related to a given history of soil use and management and to the momentary, surface physical conditions created by tillage and residue-cover treatments, applied immediately before erosion tests. A sandy clay loam Ultisol with 0.115 m m-1 average slope steepness was used. Four crop sequences were studied in no-till, under tillage (disking) and under mulch-cover (crop residue). Three erosion tests of simulated rainfall were performed with a rotating-boom rainfall simulator, each of them at a rainfall intensity of 64 mm h-1 during 1.5 h. The root mass of dead plants, soil aggregate mean-weight diameter, soil and water loss were determined. In the freshly-tilled soil (loose and rough surface) water infiltration in the soil was higher, contrasting with the lower water loss than in the untilled soil (firm and smooth surface), even though the former was bare and the later was either bare or mulched. There were also differences among the crop sequences. Soil loss was small in all crop sequences in the untilled, mulch-covered soil, while in the bare, untilled or freshly-tilled soil it was only small in the crop sequences that produced high amounts of dead plant root mass and where the soil aggregate mean-weight diameter was high. In the freshly-tilled, bare soil with high values of these two latter variables, the decrease in soil loss was due to the surface roughness created by tillage. The relationships of total water loss (declining) and total soil loss with dead plant root mass and with soil aggregate mean-weight diameter were significant at 5 %.

As diferentes práticas agrícolas realizam controles distintos na dinâmica do C e N microbiano. Com o objetivo de elucidar a dinâmica do C e N microbianos em solos sob sistema plantio direto (SPD), foram avaliados - nas seqüências milho/trigo/soja e soja/trigo/soja cultivadas em solos com diferentes classes texturais - áreas e tempos de adoção do sistema na Fazenda Santa Branca, Tibagi, PR. O experimento foi instalado em quatro áreas, sendo três delas com histórico de 12 anos sob SPD, com as seguintes classes texturais: muito argilosa (PD12-TmuA); argilosa (PD12-TA) e média (PD12-TmeA); e uma com histórico de 22 anos sob SPD com classe textural argilosa (PD22-TA). No período de 18 meses foram realizadas nove amostragens de solo em quatro camadas (0-2,5; 2,5-5; 5-10; 10-20 cm). Em função do tempo de adoção do SPD, ocorreram diferenças no C microbiano entre a PD12-TA e a PD22-TA nas camadas mais profundas do solo. A PD22-TA apresentou em média 30,8 kg ha-1 de Nmic a mais que a PD12-TA e menores variações nas quantidades de N microbiano na camada de 0-20 cm. No que se refere à textura do solo, a PD12-TmuA apresentou as maiores médias de C e N microbianos na camada de 0-20 cm, exceto nos 20 dias após o plantio do trigo (jun./01). A PD12-TA e a PD12-TmeA não apresentaram diferenças significativas nas quantidades de C microbiano em qualquer dos meses analisados, na camada de 0-5 cm. Entretanto, foram encontradas diferenças quanto a esta última propriedade nas camadas de 5-10 e 10-20 cm. Os resultados indicam que o tempo de adoção do sistema plantio direto e o aumento dos teores de argila do solo favorecem os aumentos de C e N microbianos.Different agricultural practices accomplish distinct controls on microbial C an N dynamics. The dynamics of microbial C and N in soils under no-tillage system (NT) were evaluated in the crop sequences corn/wheat/soybean and soybean/wheat/soybean in soils with different texture, areas and periods under NT at the "Santa Branca" farm, Tibagi, Paraná State, Brazil (50 ° 23 ' W, 24 ° 36 ' N). The experiment was installed at four sites, three of which had been NT cultivated in the previous 12 years, with the following textures: clay (PD12-TmuA); sandy-clay (PD12-TmeA), and sandy-clay-loam (PD12-TA); and one site 22 years under NT with texture class sandy-clay-loam (PD22-TA). During an 18 months period soils were sampled nine times in four layers (0-2.5; 2.5-5; 5-10 and 10-20 cm). Microbial C was different in PD12-TA and PD22-TA in the deepest soil layers, due to the time of NT implantation. The microbial N level in the PD22-TA averaged 30.8 kg ha-1 higher than in PD12-TA, while the variations in microbial N in the 0-20 cm layer were smaller. No significant differences were observed in the amounts of microbial C and N among the crop sequences. Regarding soil texture, the averages of microbial C and N in the 0-20 cm layer were higher for PD12-TmuA, except 20 days after wheat sowing (Jun/01). Contrasting to the 5-10 and 10-20 cm layers, in PD12-TA and PD12-TmeA the differences between microbial C levels were not significant in the 0-5 cm layer. Our results indicate that the amount of microbial C and N is favored by long-term NT and the clayey soil texture.

Row croppers in the Southeast United States (SE US) are interested in diversifying their cropping systems and increasing revenue by growing a winter cash crop between summer crops, especially cotton (Gossypium hirsutum L.) and peanut (Arachis hypogaea L.). Double-cropping carinata (Brassica carinata A. Braun) between summer crops has potential to boost grower revenue and increase land use efficiency in the region. Given that this winter crop is fairly new in the SE US, its successful establishment in the region depends on its rotational fit into current cropping systems. Since incorporating carinata into the existing cropping systems in the region could influence the productivity of those systems, it is crucial to determine what changes row croppers should expect. To resolve this, research was conducted to quantify the effects of summer cropping history on the performance of carinata as part of diversified crop rotations in the SE US. A randomized complete block design with eight replications was implemented in Jay, Florida, over three years. Summer cropping history treatments were peanut, cotton, and summer fallow. Data was collected on carinata aboveground biomass and stover [including carbon (C) and nitrogen (N)]; yield (including yield components); and seed chemical composition (glucosinolates concentration, protein and oil contents, and oil composition). Carinata biomass, biomass C and N, stover residue, stover residue C and N, and stover residue C:N ratio were not affected by summer cropping history across years. Likewise, yield and seed chemical composition were not affected by summer cropping history. In terms of combined productivity of summer crops and carinata, cotton-carinata was the most productive system while fallow-carinata was the least productive. Overall, results from this study show that the insensitivity of carinata yield or seed quality to previous summer crops allows for flexibility in integrating carinata into existing rotations in the SE US. This simplifies the agronomic management of carinata as a biofuel crop since growers can concentrate on meeting yield goals without the risk of affecting yield or seed quality with different summer cropping histories. • Carinata was evaluated for yield and seed quality following cotton, peanut, and fallow cropping histories. • Carinata can be grown after cotton or peanut without compromising yield or seed quality. • Carinata has potential to be a fallow replacement winter crop for producing jet fuel in the Southeast US. [ABSTRACT FROM AUTHOR]

Neste estudo foram avaliados atributos qualitativos e quantitativos da microbiota do solo, visando monitorar alterações por diferentes manejos do solo e das culturas. As avaliações foram feitas em um ensaio a campo, conduzido há 14 anos em Londrina, PR, sob plantio convencional (PC) ou plantio direto (PD) e com sucessão (S) (soja/trigo) ou rotação (R) (tremoço/milho/aveia-preta/soja/trigo/soja/trigo/soja) de culturas, quando todos os sistemas estavam com soja no estádio de florescimento pleno. Os incrementos no C e N da biomassa microbiana (CBM e NBM) no PD foram de 114 e 157 %, respectivamente, em comparação ao PC; além disso, o quociente metabólico (qCO2) foi inferior em 37 % no PD, indicando maior eficiência metabólica da microbiota do solo. Não foram detectadas diferenças nesses atributos em função dos sistemas de rotação e sucessão de culturas. A diversidade genética da comunidade bacteriana total do solo foi superior no PD e inferior no PC com sucessão de culturas. Em relação à fixação biológica do N2, a massa, o N total e a fração de N-ureídos acumulados na parte aérea e a eficiência dos nódulos em fixar N2 foram superiores no PD. A diversidade genética dos rizóbios foi afetada, principalmente, pelo manejo das culturas, sendo superior com a rotação, provavelmente pelo maior número de espécies de plantas. Contudo, com a rotação ocorreu decréscimo na eficiência do processo de fixação biológica do N2, o que pode estar relacionado com os teores mais elevados de N no solo, ou com a menor pressão de seleção por bactérias eficientes. Desse modo, para microrganismos do solo com função específica, como os rizóbios, a diversidade genética pode ser distinta da funcionalidade.In this study, quantitative and qualitative microbiological parameters were evaluated to detect differences related to soil and crop management. The study was carried out in a field experiment installed 14 years ago on a Rhodic Eutrudox, in Londrina, PR, Brazil. Treatments were a combination of a crop sequence (S) (soybean/wheat) and a crop rotation (R) (lupin/maize/black oat/soybean/wheat/soybean/wheat/soybean), either under conventional tillage (CT) or no-tillage (NT). Evaluations were performed when all systems were under the soybean cropping season, at full flowering. Amounts of microbial biomass carbon and nitrogen (MB-C and MB-N, respectively) were 114 and 157 % higher in NT than in CT. Furthermore, the metabolic quotient (qCO2) was lower under NT, indicating higher metabolic efficiency of the soil microbes. These parameters were not affected by the crop sequence/rotation. Genetic diversity of the total soil bacterial community was higher under NT and lower in the CT system with crop sequence. Regarding the biological N2 fixation, it was found that plant biomass, total N and fraction of N-ureides in shoots, as well as nodule efficiency, were higher under NT. Genetic diversity of rhizobia was affected mainly by crop management and was higher under crop rotation, probably due to the greater number of plant species. However, crop rotation decreased the efficiency of the biological N2 fixation process, which may be related to more abundant N in the soil or to a lower selection pressure for efficient rhizobia. For soil microbes with specific functions, e.g., rhizobia, genetic diversity may therefore differ from functionality.

Agronomical and agro-environmental diagnosis of crop sequences in Wallonia (Belgium). Crop sequence, recognized as a fundamental concept providing a balance both agronomic at parcel level and agro-environmental at the agro-ecosystem level, is analyzed on the scale of the Walloon agricultural regions (Belgium). This study aims to make a diagnosis of the qualitative performances of crop sequences, through the individual analysis of some of their explanatory components such as the effect of the previous crop on the next one, the observed return time of the re-occuring crops, the number of crops observed during the sequence and finally the duration of intercrop period. These four components are analyzed at parcel level, the results being aggregated at regional level. Study concerns both a spatial analysis based on a period of 7 years, and a temporal analysis aiming to observe a possible evolution, region by region, during two successive and equivalent periods. The drawn up appraisal reveals spatial differences in terms of practices linked to crop sequences, on the other hand, one quasi temporal stability of the analyzed parameters emerges from obtained results. Besides, these results constituting a contribution to an appraisal of the agriculture in Wallonia may serve as reference values for an evolution of regional agricultural practices global follow-up.

The aim of the present investigation was to improve the productivity of calcareous sandy soil of Arab El-Awammer Experimental Station, Assiut governorate, Egypt. For this purpose a field experiment under minimum soil tillage conditions in summer season of 2010 was conducted in split split plot design with three replicates to detect the production of maize and soil fertility as influenced by previous and immediately some soil cultural treatments in main plot, levels of powder elemental S (zero and 300 kg S/fed) in the sub plots and mineral nitrogen fertilization levels (120 and 180 kg N/fed) in the sub sub plots. The four soil cultural treatments in main plots were two different crop sequences with crop residues completely removed (-CR) or with crop residues incorporated in soil surface layer 0-25 cm (+CR). The different two crop sequences (depend on it's inclusions from legume crop) were:- Year 2009 2010 legume crop% Sequence 1 = wheat - maize - wheat - maize (0%) Sequence 2 = wheat - maize - clover - maize (25%) The obtained results from the maize crop cultivated in season four of this study show that, crop residues applied in legume cereal cropping systems (25% legume crops) resulted in higher maize growth, yields, yields components, NP uptake by maize plants and improved soil fertility (soil organic matter content, soil total N, soil available P and soil pH). Powdered elemental S applied seasonally at a level of 300 kg S/fed and N-fertilizer at the high levels (180 kg N/fed) were also efficient in improving maize productivity and improving fertility status of calcareous sandy soil.The study recommends that seasonally application of crop residues in legume cereal cropping systems with seasonally application of powdered elemental S at a level of 300 kg S/fed and N-fertilizer at the height levels (180 kg N/fed) is the best treatment for producing high production of maize crop and improving fertility status of calcareous sandy soil. [ABSTRACT FROM AUTHOR]

Organic producers would like to include no-till practices in their farming systems, but they are concerned about managing weeds without tillage. We are seeking to develop a continuous no-till system for organic farming, based on a complex rotation that includes a 3-yr sequence of alfalfa. In this study, we evaluated impact of preceding crop on weed infestation in alfalfa. Alfalfa was established with no-till following spring wheat, corn or soybean. The study involved a 4-yr interval, with weed dynamics measured in the fourth year. Alfalfa established after soybean suppressed weeds more than alfalfa established after spring wheat or corn. Weed biomass in alfalfa following spring wheat was 18% of the plant community, but only 1% when alfalfa followed soybean and 6% when alfalfa followed corn. Weed biomass increased because alfalfa density following spring wheat was only 71% of alfalfa following soybean. Weeds such as downy brome (Bromus tectorum L.) and dandelion (Taraxacum officinale Weber) were able to establish and produce biomass where alfalfa stand was sparse. Alfalfa forage yield across 3 yr was also higher following soybean than either spring wheat or corn. Alfalfa competitiveness with weeds can be improved by choice of preceding crop. [ABSTRACT FROM PUBLISHER]

Nitrogen (N) mineralization during a short anaerobic incubation (NAN) could be used as a soil health indicator. To adjust its use, it is necessary to characterize and understand how it is affected by different management practices. For soils of the Southeast of the Buenos Aires Province we hypothesized that i) higher carbon (C) inputs through crop residues lead to lower NAN variations in the arable soil layer without difference between conventional tillage (CT) and no tillage (NT), and ii) the amount and quality of the preceding crop residue affects the NAN content. The aims of this work were: i) to evaluate the change in time of NAN at 0-20 cm under different crop sequences, CT and NT, and with and without N fertilization (NF), and ii) to analyze the effect of different crop residues on NAN at 0-20 cm. We determined NAN in stored soil samples taken from the 0-5 and 5-20 cm soil layers in two long term tillage system (TS) experiments (CT and NT): Experiment 1 with two levels of NF (with and without N), and Experiment 2: with three crop sequences (corn-corn-wheat, corn-soybean-wheat, soybean-soybean-wheat). Anaerobic N decreased along years under cropping at 0-5, 5-20 y 0-20 cm, under both TL and levels of NF. Only at 0-5 cm decreases were significantly different between TS (CT>NT). At 0-20 cm there were no differences in NAN decreases neither between levels of NF nor among crop sequences. Hence, different C inputs of different biomass productions did not lead to differential changes in NAN along cropping years. Different preceding crops did neither affect NAN contents. Nitrogen fertilization could have produced higher soil organic C mineralization since it decreases the soil system C/N ratio, masking the expected effects of crop residue characteristics on NAN. However, our results contribute to confirm the feasibility of using NAN as a soil health indicator. [ABSTRACT FROM AUTHOR]