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Legumes can be integrated into cereal crop systems as a service crop to fix nitrogen, support cereal grain quality, and provide fodder for animals. However, competitive effects on cereal crop yields need to be avoided as much as possible. Here, we study the effect of seven legume species on yield, yield components and grain quality of rice, in dependence of the relative sowing time of the legume and the spatial configuration of the intercrop. In the first year, legume species were sown simultaneously with rice as well as at 25 days after rice emergence (DARE). Based on the first year, legume species were only sown at 25 DARE in the second year, but in two spatial configurations: alternate and double row design. Rice grain yield and total dry mass were negatively associated, showing the difficulty in obtaining an increased biomass production without giving in on rice grain yield. There are legumes species (Crotalaria spectabilis, jack bean and dwarf pigeon pea) that compete more with upland rice than others and legumes sowing at 25 DARE and in double rows reduces this competitive effect. Overall, upland rice intercropped with C. breviflora presented a higher total dry mass production than sole rice, without affecting grain yield. The crude protein content of rice grains was higher in intercrops in which grain yield was reduced by legumes due to the dilution effect. The adjustments in sowing time and spatial arrangement increased the range of legume species that can be used to promote ecological benefits without negatively affecting rice yield and quality, enabling diversification of species and biomass in the same area, associating food production with the benefits of the legume ecosystem services. [ABSTRACT FROM AUTHOR]

Rice residue burning poses a significant challenge in the rice-wheat cropping system of India, leading to environmental pollution, health issues, and substantial nutrient loss. To combat this menace, a three-year study (2020-21 to 2022-23) was conducted, investigating the effects of rice residue retention (RRR) and rice residue incorporation (RRI) at graded N levels (0, 50, 100, 150, and 200 kg/ha) alongside farmers' practices. The primary objective was to enhance wheat productivity, profitability, and soil fertility within this system. Pooled analysis revealed that RRR outperformed RRI at lower nitrogen doses, while RRI excelled with 7.5%, 7.4%, and 10.0% higher biological yields at higher nitrogen doses (100, 150, and 200 kg/ha). The success of RRR and RRI was attributed to 10.5% and 5.0% higher effective tiller/m2, respectively, compared to farmers' practices at 150 kg N/ha. Notably, RRR exhibited superior NDVI values at the flag leaf stage (0.76) over farmers' practices (0.73). At the 150 kg N/ha, RRR displayed a 9.6% lower cost of cultivation compared to farmers' practices, with 19.6% higher net returns at lower N levels (50 kg/ha), suggesting its greater benefits under low-input conditions. Furthermore, RRR showed the highest benefit-cost ratio (2.75) at 150 kg N/ha, followed by RRI (2.59) and farmers' practices (2.55). Over the three-year period, RRR significantly increased organic carbon content (0.49–0.54%) compared to the initial value (0.38%), affirming its long-term benefits. Consequently, the adoption of RRR by farmers is a preferable eco-friendly option over RRI and present practices for enhancing wheat productivity within the rice-wheat system. Due to 60–65% saving of fuel with the practice of zero tillage along with rice residue retention, it can reduce CO2 emission by 120 kg/ha, therefore, its implementation can reduce CO2 release by 1.62 MT in South Asia per year. Ultimately, it can meet the target of Paris Agreement of limiting global warming to 1.5 °C above pre-industrial levels and reaching net-zero CO2 emissions globally by 2050. [ABSTRACT FROM AUTHOR]

Cover cropping plays an important role in Integrated Weed Management (IWM). Weed suppression of cover crops occurs by competition, physical barrier on the soil and allelopathy. Under favourable growing conditions, cover crops can provide similar weed suppression in the autumn‐to‐spring period as repeated stubble tillage and non‐selective herbicides. The objective of this study was to test if cover crop species with higher allelopathic potential can suppress weeds in the field with less shoot biomass than cover crop species with lower allelopathic effects. Data of cover crop shoot biomass, percentage of weed suppression in the field and reduction of weed seed germination in petri‐dish bioassays treated with cover crop extracts were analysed from 11 experiments. Weed suppression in relation to cover crop biomass was better predicted by a Weibul three‐parameter model than with the Cousens model. Raphanus sativus var. oleiferus, Sinapis alba, Fagopyrum esculentum and Phacelia tanacetifolia needed at least three‐fold more biomass than Avena strigosa for 80% weed suppression. Vicia sativa had the lowest weed reduction of only 62%. Aqueous extracts of A. strigosa had the highest inhibiting effect on weed seed germination followed by R. sativus. The lowest effect was observed for P. tanacetifolia. It is assumed that for A. strigosa allelopathy strongly contributes to weed suppression whereas for P. tanacetifolia and other cover crops, competition plays the major role for weed suppression. The model can help growers and consultants to mix cover crop species for the autumn‐to‐spring period. Under dry conditions, species such as A. strigosa can provide high weed suppression with low biomass. Under moist conditions, rapidly growing cover crops such as S. alba suppress most weeds and deliver high biomass. [ABSTRACT FROM AUTHOR]

Winter cereal rye (Secale cereale L.) (WCR) is often double cropped with maize for silage (Zea mays L.) to increase farm forage supply and profit. Spring nitrogen (N) fertilization to WCR could influence its production and quality at different harvesting times. Therefore, two on‐farm trials were conducted in the 2019–2020 and 2020–2021 growing seasons to evaluate the effect of harvesting time (late‐March to end‐of‐April considering the growth stage) and spring N fertilization (0, 23, 47, and 71 kg N ha−1) on WCR morphology, forage yield, nutrient removal, quality, and farm profit. Only two N treatments (0 and 47 kg N ha−1) were evaluated for each harvesting time in trial 1. A quadratic model best explained an increase in WCR dry matter (DM) yield in response to growing degree days (GDD) accumulation (R2 = 0.81). An increase in GDD linearly decreased WCR relative forage quality (RFQ). Benchmarking RFQ at 150 for dairy milk production indicates WCR should be harvested at a GDD of 543, at which WCR plant height was 31.8 cm and DM yield was 0.77 Mg ha−1. This resulted in loss of profit in both study years compared to later harvesting dates at higher GDDs. Benchmarking RFQ at 125 for heifer production indicated that harvest should occur at a GDD of 668, at which the WCR was 71 cm tall, and its DM yield was 2.25 Mg ha−1. Nitrogen balances were negative at the N0 treatment (0 kg N ha−1), indicating a need for some N to maximize WCR yield. We found that a rate between 21 and 47 kg N ha−1 maximizes yields reflecting slightly positive balances, in which the highest profits occur. Our results suggest that the harvesting time can be predicted by GDD and should be adjusted for RFQ. We conclude that less than 47 kg N ha−1 N fertilizer is required for WCR production in soils with manure history and high soil organic matter (>30 g kg−1). [ABSTRACT FROM AUTHOR]

Dairy farms in the United States have changed in many ways over the past 50 yr. Milk production efficiency has increased greatly, with ∼30% fewer cows producing about twice the amount of milk today. Other improvements include increases in crop yields, fuel efficiency of farm equipment, and efficiency in producing most resources used on farms (e.g. electricity, fuel, fertilizer). These improvements have led to changes in the environmental impact of farms. Through simulation of representative dairy farms in 1971 and 2020, changes in nutrient losses and farmgate life cycle assessments of greenhouse gas (GHG) emissions, fossil energy use, and blue (ground and surface) water use were determined for 6 regions and the United States. For all environmental metrics studied, intensities expressed per unit of fat- and protein-corrected milk produced were reduced, but the total effects over all farms or milk produced increased for 5 of the 13 environmental metrics. Reductions in the impacts of dairy farms in the eastern United States were offset by large increases in western regions because of a major increase in cow numbers in the West. The national average intensity of GHG emissions decreased by 42%, which gave just a 14% increase in the total GHG emissions of all dairy farms over the 50-yr period. The intensity of fossil energy use decreased by 54%, with the total for all farms decreasing by 9%. Water use related to milk production decreased in intensity by 28%, but due to the large increase in dairy production in the dry western regions that have a greater dependence on irrigated feed crops, total blue water use increased by 42%. Major pathways of nitrogen loss included ammonia volatilization, leaching, and denitrification, where total ammonia emissions related to US dairy farms increased by 29%, while leaching losses decreased by 39%, with little change in nitrous oxide emissions. Simulated nitrogen and phosphorus runoff losses totaled for all dairy farms decreased by 27% to 51% through more efficient fertilizer use, reduced tillage, and greater use of cover crops. Emissions of methane and reactive non-methane volatile organic compounds increased by 32% and 53%, respectively, due to greater use of long-term manure storage and silage stored in bunkers and piles. Although much progress has been made in improving production efficiency, continued improvements with new strategies and technologies are needed to meet the demand for dairy products and mitigate total environmental impacts, particularly in view of projected climate variability. [ABSTRACT FROM AUTHOR]

Termination methods and the timing of the termination of the cover crops are critical factors determining the efficacy of cover crops in improving soil fertility and quality. We hypothesized that different termination methods will produce varying quantities of organic residue which will affect microbial diversity and thereby nutrient cycling and availability. The objective of this study was to compare termination methods (roller-crimper, flail mowing, rotary mowing, sickle bar mowing, and occultation using black tarps) for fall-grown cover crop combination (hairy vetch-cereal rye) under organic vegetable production. Field experiments were carried out in three consecutive years (2018–2021) and soil samples were collected from 0 to 15 cm and processed for analysis. Soil organic matter content, nutrients, health parameters, enzymes, and microbial diversity were measured. Flail mowing significantly enhanced the potentially mineralizable nitrogen, available phosphorus, and active carbon. Total Phospholipid Fatty Acid (PLFA) analysis showed a 24% increase for flail mowed, 17% for rotary mowed, and 15% for sickle bar mowed termination methods. There was a significant increase in active carbon content which ranged from 38.9% (rotary mowed), 25.4% (sickle bar mowed), 23.5% (flail mowed), 16.4% for crimper rolled method, and with 2.8% (occultation) respectively. Individual termination methods had varying effects on select enzyme activities. Results indicated that integrating cover crops has the potential to modify soil microbial community structure and increase soil enzyme activities. In this study, flail mowing appeared to be a good method for managing cover crops of choice in terms of soil microbial functionality and fertility. [ABSTRACT FROM AUTHOR]

Cover crops have the potential to mitigate climate change by reducing negative impacts of agriculture on ecosystems. This study is first to quantify the net climate change mitigation impact of cover crops including land-use effects. A systematic literature and data review was conducted to identify major drivers for climate benefits and costs of cover crops in maize (Zea maize L.) production systems. The results indicate that cover crops lead to a net climate change mitigation impact (NCCMI) of 3.30 Mg CO2e ha-1 a-1. We created four scenarios with different impact weights of the drivers and all of them showing a positive NCCMI. Carbon land benefit, the carbon opportunity costs based on maize yield gains following cover crops, is the major contributor to the NCCMI (34.5% of all benefits). Carbon sequestration is the second largest contributor (33.8%). The climate costs of cover crops are mainly dominated by emissions from their seed production and foregone benefits due to land use for cover crops seeds. However, these two costs account for only 15.8% of the benefits. Extrapolating these results, planting cover crops before all maize acreage in the EU results in a climate change mitigation of 49.80 million Mg CO2e a-1, which is equivalent to 13.0% of the EU's agricultural emissions. This study highlights the importance of incorporating cover crops into sustainable cropping systems to minimize the agricultural impact to climate change. [ABSTRACT FROM AUTHOR]

Crop-specific cultivation practices including crop rotation, cover cropping, and fertilisation are key measures for sustainable farming, for which soil microorganisms are important components. This study aims at identifying links between agronomic practices, potato yield and quality as well as soil microorganisms. We analysed the roles of cover crops and of the soil prokaryotic, fungal, and protistan communities in a long-term trial, differing in crop rotation, i.e. winter wheat or silage maize as pre-crop, presence and positioning of oil radish within the rotation, and fertilisation, i.e. mineral fertiliser, straw, manure, or slurry. Up to 16% higher yields were observed when oil radish grew directly before potatoes. Losses of potato quality due to infection with Rhizoctonia solani-induced diseases and common scab was 43–63% lower when wheat + oil radish was pre-crop under manure or straw + slurry fertilisation than for maize as pre-crop. This contrast was also reflected by 42% higher fungal abundance and differences in β-diversity of prokaryotes, fungi, and protists. Those amplicon sequence variants, which were found in the treatments with highest potato qualities and differed in their abundances from other treatments, belonged to Firmicutes (2.4% of the sequences) and Mortierellaceae (28%), which both comprise potential antagonists of phytopathogens. Among protists, Lobosa, especially Copromyxa, was 62% more abundant in the high potato quality plots compared to all others, suggesting that specific higher trophic organisms can improve crop performance. Our findings suggest that successful potato cultivation is related (1) to planting of oil radish before potatoes for increasing yield and (2) to fertilisation with manure or straw + slurry for enriching the microbiome with crop-beneficial taxa. [ABSTRACT FROM AUTHOR]

Crop N decision support tools are typically based on either empirical relationships that lack mechanistic underpinnings or simulation models that are too complex to use on farms with limited input data. We developed an N mineralization model for corn that lies between these endpoints; it includes a mechanistic model structure reflecting microbial and texture controls on N mineralization but requires just a few simple inputs: soil texture soil C and N concentration and cover crop N content and carbon to nitgrogen ratio (C/N). We evaluated a previous version of the model with an independent dataset to determine the accuracy in predictions of unfertilized corn (Zea mays L.) yield across a wider range of soil texture, cover crop, and growing season precipitation conditions. We tested three assumptions used in the original model: (1) soil C/N is equal to 10, (2) yield does not need to be adjusted for growing season precipitation, and (3) sand content controls humification efficiency (ε). The best new model used measured values for soil C/N, had a summertime precipitation adjustment, and included both sand and clay content as predictors of ε (root mean square error [RMSE] = 1.43 Mg ha−1; r2 = 0.69). In the new model, clay has a stronger influence than sand on ε, corresponding to lower predicted mineralization rates on fine‐textured soils. The new model had a reasonable validation fit (RMSE = 1.71 Mg ha−1; r2 = 0.56) using an independent dataset. Our results indicate the new model is an improvement over the previous version because it predicts unfertilized corn yield for a wider range of conditions. Core Ideas: An improved N mineralization model predicts unfertilized corn yield for a wide variety of conditions.The new model provides realistic estimates of microbial humification efficiency across a range of soil textures.Humification efficiency is affected more by soil clay content than sand content.The updated coefficients account for the influence of precipitation on corn yield.The improved model provides a foundation for site‐specific N fertilizer recommendations. [ABSTRACT FROM AUTHOR]

Wind erosion and variable weather challenge crop production in the northern Great Plains. Management that increases residue cover might mitigate wind erosion during the cash crop growing season. We evaluated horizontal sediment flux (modified Wilson and Cooke samplers) and cash crop yield across a single rotation of corn (Zea mays L.)–soybean (Glycine max (L.) Merr.)–spring wheat (Triticum aestivum L.) in paired fields with contrasting management. One field included cover crops and retained spring wheat straw (aspirational), while the other excluded both conservation practices over the 3‐year rotation (business‐as‐usual). Horizontal sediment flux rapidly decreased with days after cash crop planting (increasing crop canopy), regardless of management treatment. In 2 years (2020 corn and 2022 spring wheat), there was greater horizontal sediment flux, lower cash crop grain yield, and lower cash crop aboveground biomass in the aspirational versus business‐as‐usual field. In 2021 soybean, there was lower horizontal sediment flux, greater cash crop yield, and greater cash crop aboveground biomass in the aspirational versus business‐as‐usual field. Higher yield and lower horizontal sediment flux responses corresponded with the management treatment that produced the higher cash crop aboveground biomass. Additionally, our short‐term study indicated that in drought years, cover crops worsened the adverse effects of abnormally low precipitation on yield and biomass of 2020 corn but not 2021 soybean. Core Ideas: Sediment mass flux and grain yield were measured in response to cover cropping and wheat straw management.Horizontal sediment flux rapidly decreased with canopy development, regardless of management treatment.During drought, cover crops decreased yield and biomass of corn but not soybean.Conservation practices treatment had lower horizontal sediment flux in 2021 soybean, but not in 2020 or 2022. [ABSTRACT FROM AUTHOR]

Soil hydraulic and physical properties can be influenced by various land management practices, and they determine water movement and storage within the vadose zone, with both agronomic and environmental effects. The objective of this study was to evaluate the effects of two such practices (no‐till [NT] and cover crops [CCs]) on soil hydraulic (e.g., saturated hydraulic conductivity [Ksat], and water retention) and physical (e.g., bulk density [BD], pore size distribution, air‐filled pore spaces [AFPSs], and water‐filled pore spaces [WFPSs]) properties. The CCs used included crimson clover (Trifolium incarnatum L.), hairy vetch (Vicia villosa Roth.), winter peas (Lathyrus hirsutus L.), oats (Avena sativa), winter wheat (Triticum aestivum L.), triticale (Triticale hexaploide Lart.), flax (Linum usitassimum L.), and barley (Hordeum vulgare L.). Soil samples were collected and analyzed during 2021 and 2022 right before CC termination at 0‐ to 10‐cm, 10‐ to 20‐cm, and 20‐ to 30‐cm depths. Results showed that, during 2021 and 2022, BD was 18% and 14% higher, respectively, under NC compared with CC management, while Ksat was 2.2 and 1.9 times higher, respectively, under CC compared with NC management. Further, the non‐capillary pores were significantly (p ≥ 0.05) higher under CC compared with NC management during both years of study. As a result, the majority of the total pores under CCs were filled with air, while the majority of total pores under NC management were filled with water. Therefore, this CC mix may be useful in lengthening the growing period during wet seasons by increasing air‐filled pore spaces. Core Ideas: NT cover crops (CCs) significantly lowered BD and increased saturated hydraulic conductivity compared with no cover crop management.During 2 years, the van Genuchten α and n parameters were higher under CC management.CCs improved the proportion of capillary and non‐capillary pores.CCs increased the proportion of total pores filled with air.Under CC management alone, most soil properties were similar during 2 years. [ABSTRACT FROM AUTHOR]

The document provides information about the recipients of the 2023 awards from the Soil Science Society of America (SSSA). The recipients come from diverse backgrounds and are pursuing degrees and conducting research in various areas of soil science and agronomy. Their research focuses on topics such as crop science, soil health, plant pathogen interactions, and water resources. These individuals have demonstrated leadership, academic excellence, and a commitment to advancing sustainable agriculture practices. The document also includes profiles of individuals involved in the field of agronomy and plant science, as well as highlighting the recipients of the SSSA Presidential Award, specifically recognizing the SSSA Diversity Trailblazers who have made important contributions as women, people of color, indigenous individuals, and LGBTQ+ scientists in leadership roles within the society. [Extracted from the article]

The understanding of how solitary and combined use of covercrop species and seeding rates influences soilborne diseases is lacking. Cover crops (crimson clover, triticale and crimson clover + triticale) were seeded in the field plots in September 2019 (Trial 1) and September 2021 (Trial 2) at two seeding rates (low and high) and a no cover cropped fallow served as a control. The soil was collected from all the plots in the following June. Red maple rooted cuttings were planted in nursery containers filled with those soils and plant health was evaluated with and without inoculation with Phytophthora nicotianae, Phytopythium vexans and Rhizoctonia solani. Plant height and fresh weight were measured, and plant roots were assessed for root rot severity (0–100% roots affected) and pathogen recovery. The number of fluorescent Pseudomonads present in soil samples was counted. Root rot severity and pathogen recovery were less with plants grown in cover cropped soil compared to non-cover cropped soil. Root rot severity caused by all three pathogens was least with the plants grown in the crimson clover and mixed cover cropped soil with the mixture being better than crimson clover. Moreover, plants grown in the high rate of cover cropped soil had less root rot severity compared to plants grown in low seeding rate cover cropped soil. Plant fresh weight was greater for plants grown in the high rate of crimson clover cover cropped soil and, in the mixture, compared to the non-cover cropped soil, whereas height was least affected. The Pseudomonad population was greatest in mixed cover cropped as well as in the high rate of cover cropped soil. Our findings suggest that a mixture of cover crop species and high seeding rate provides better service in suppressing root rot diseases likely associated with biological processes and nutrient availability. [ABSTRACT FROM AUTHOR]

Diversification of agricultural practices, including changes in crop rotation, intercropping or cover cropping, influence the soil microbiome. Here the impact of tillage and crop diversification on the soil microbiome is reported, being one of the few boreal studies. The field experiment consisted of four treatments with four replications all having a short cereal rotation practice namely an oat (Avena sativa) – spring barley (Hordeum vulgare) – wheat (Triticum aestivum) rotation for the past 10 years until spring 2018. During that period two of the treatments were conventionally tilled with moldboard ploughing whereas the other two were no-tillage treatments. From the growing season 2018 until fall 2020 the main crop in all treatments was spring barley. The first conventional tillage treatment was diversified with English ryegrass (Lolium perenne) as an undersown cover crop for the next three growing seasons. The first no-tillage treatment continued with spring barley only. The second conventional tillage and no-tillage treatment had winter rapeseed in rotation in 2019. Bulk soils were sampled in May 2018 before diversification and then in October 2018, 2019, and 2020. The results showed a clear effect of tillage on the beta-diversity of the soil microbiome and an increase in fungal richness. Barley monoculture interrupted with winter rapeseed resulted in a minor change of the fungal and bacterial community composition. Other fungal and bacterial alpha diversity measures did not react to tillage or diversification nor did the gene copy abundances involved in the N cycle. In conclusion tillage had a profound effect on the soil microbiome hindering impact of the diversification. [ABSTRACT FROM AUTHOR]

Winter cover crops are planted during the fall to reduce nitrogen losses and soil erosion and improve soil health. Accurate estimations of winter cover crop performance and biophysical traits including biomass and fractional vegetative groundcover support accurate assessment of environmental benefits. We examined the comparability of measurements between ground-based and spaceborne sensors as well as between processing levels (e.g., surface vs. top-of-atmosphere reflectance) in estimating cover crop biophysical traits. This research examined the relationships between SPOT 5, Landsat 7, and WorldView-2 same-day paired satellite imagery and handheld multispectral proximal sensors on two days during the 2012–2013 winter cover crop season. We compared two processing levels from three satellites with spatially aggregated proximal data for red and green spectral bands as well as the normalized difference vegetation index (NDVI). We then compared NDVI estimated fractional green cover to in-situ photographs, and we derived cover crop biomass estimates from NDVI using existing calibration equations. We used slope and intercept contrasts to test whether estimates of biomass and fractional green cover differed statistically between sensors and processing levels. Compared to top-of-atmosphere imagery, surface reflectance imagery were more closely correlated with proximal sensors, with intercepts closer to zero, regression slopes nearer to the 1:1 line, and less variance between measured values. Additionally, surface reflectance NDVI derived from satellites showed strong agreement with passive handheld multispectral proximal sensor-sensor estimated fractional green cover and biomass (adj. R2 = 0.96 and 0.95; RMSE = 4.76% and 259 kg ha−1, respectively). Although active handheld multispectral proximal sensor-sensor derived fractional green cover and biomass estimates showed high accuracies (R2 = 0.96 and 0.96, respectively), they also demonstrated large intercept offsets (−25.5 and 4.51, respectively). Our results suggest that many passive multispectral remote sensing platforms may be used interchangeably to assess cover crop biophysical traits whereas SPOT 5 required an adjustment in NDVI intercept. Active sensors may require separate calibrations or intercept correction prior to combination with passive sensor data. Although surface reflectance products were highly correlated with proximal sensors, the standardized cloud mask failed to completely capture cloud shadows in Landsat 7, which dampened the signal of NIR and red bands in shadowed pixels. [ABSTRACT FROM AUTHOR]

In modern agriculture, more and more attention is being paid to the use of microorganisms that can increase crop productivity and quality even under adverse weather conditions. Due to the declining biodiversity of crops and the occurrence of soil erosion and nutrient losses, the introduction of cover crops (CC) can be a positive crop management technique. In the field study presented here, the effect of growing spring barley with CCs applied simultaneously with bacterial consortia on the ratio of the total number of bacteria to actinobacteria (B/A) and the number of fungi in the soil was evaluated. The biomass yield of CCs and the subsequent effect on the yield of spelt wheat grown with the application of bacterial consortia were also evaluated. The bacterial consortia applied included consortium 1, comprising Bacillus subtilis, Bacillus amyloliquefaciens, and Pseudomonas fluorescens, and consortium 2, comprising Bacillus subtilis, Bacillus amyloliquefaciens, Pseudomonas fluorescens, and Azotobacter chroococcum. The CCs were red clover, red clover + Italian ryegrass, and Italian ryegrass. The most favorable B/A ratio and the highest number of fungi were obtained after growing spring barley with a CC consisting of a mixture of red clover and Italian ryegrass when using bacterial consortium 2. These conditions additionally had the most favorable influence on spelt wheat. The combination of such a forecrop with the application of bacterial consortium 2 resulted in the highest yields of spelt wheat. [ABSTRACT FROM AUTHOR]

The application of remote sensing, which is non-destructive and cost-efficient, has been widely used in crop monitoring and management. This study used a built-in multispectral imager on a small unmanned aerial vehicle (UAV) to capture multispectral images in five different spectral bands (blue, green, red, red edge, and near-infrared), instead of satellite-captured data, to monitor soybean growth in a field. The field experiment was conducted in a soybean field at the Mississippi State University Experiment Station near Pontotoc, MS, USA. The experiment consisted of five cover crops (Cereal Rye, Vetch, Wheat, Mustard plus Cereal Rye, and native vegetation) planted in the winter and three fertilizer treatments (Fertilizer, Poultry Liter, and None) applied before planting the soybean. During the soybean growing season in 2022, eight UAV imaging flyovers were conducted, spread across the growth season. UAV image-derived vegetation indices (VIs) coupled with machine learning (ML) models were computed for characterizing soybean growth at different stages across the season. The aim of this study focuses on monitoring soybean growth to predict yield, using 14 VIs including CC (Canopy Cover), NDVI (Normalized Difference Vegetation Index), GNDVI (Green Normalized Difference Vegetation Index), EVI2 (Enhanced Vegetation Index 2), and others. Different machine learning algorithms including Linear Regression (LR), Support Vector Machine (SVM), and Random Forest (RF) are used for this purpose. The stage of the initial pod development was shown as having the best predictability for earliest soybean yield prediction. CC, NDVI, and NAVI (Normalized area vegetation index) were shown as the best VIs for yield prediction. The RMSE was found to be about 134.5 to 511.11 kg ha−1 in the different yield models, whereas it was 605.26 to 685.96 kg ha−1 in the cross-validated models. Due to the limited number of training and testing samples in the K-fold cross-validation, the models' results changed to some extent. Nevertheless, the results of this study will be useful for the application of UAV remote sensing to provide information for soybean production and management. This study demonstrates that VIs coupled with ML models can be used in multistage soybean yield prediction at a farm scale, even with a limited number of training samples. [ABSTRACT FROM AUTHOR]

The Hessian fly (HF), Mayetiola destructor (Diptera: Cecidomyiidae), is one of the most devastating insect pests of cereals including wheat, barley, and rye. Although wheat is the preferred host for HF, this continuously evolving pest has been emerging as a threat to barley production. However, characterization and identification of genetic resistance to HF has not been conducted in barley. In the present study, we used a genome-wide association study (GWAS) to identify barley resistance loci to HF using a geographically diverse set of 234 barley accessions. The results showed that around 90% of barley lines were highly susceptible, indicating a significant vulnerability to HF in barley, and a total of 29 accessions were resistant, serving as potential resistance resources. GWAS with a mixed linear model revealed two marker-trait associations, both on chromosome 4H. The resistance loci and associated markers will facilitate barley improvement and development for breeders. In addition, our results are fundamental for genetic studies to understand the HF resistance mechanism in barley. [ABSTRACT FROM AUTHOR]

Food systems are responsible for one-third of global greenhouse gas emissions, which in turn are changing the climate and disrupting the food supply. The UN's Food and Agriculture Organization recently unveiled a "food systems roadmap" to align food production with global climate goals. The delay in recognizing the connection between food and climate change may be due to a lack of imagery. Solutions to creating more sustainable food systems include using genetic editing tools to develop crops with increased yields and resilience, as well as reviving traditional indigenous food sources. Another approach is regenerative agriculture, which focuses on enriching the soil and environment through practices like cover cropping and integrated pest management. Despite the challenges, there are various approaches available to transform the food system in the face of climate change. [Extracted from the article]

Dryland wheat farming commonly uses a rotation of wheat to fallow between years but growers have begun to diversify crop rotations for a variety of environmental and economic reasons. Ethiopian mustard (Brassica carinata A.) and camelina (Camelina sativa L.), two oil seed crops, can be successfully grown in the Northern Great Plains (NGP) and could be a suitable fallow replacement. Native bees have declined in abundance and richness primarily due to conversion of natural habitat to row crops and honey bees have become increasingly difficult to manage in recent years. Thus, it is important to determine how flower visiting insects utilize novel crops. We collected flower visiting insects via weekly sweep netting events during two growing seasons to determine abundance and richness of bees and other insect pollinators on B. carinata, C. sativa, and a ten species cover crop. Overall, numerous native bees and other flower visiting insects were collected off all three potential fallow replacements. These crops may provide important floral resources for bees and other pollinators and could be used to improve pollinator resources within cropping systems of the NGP. [ABSTRACT FROM AUTHOR]

In soils, pH stands as the main factor modulating bacterial communities' composition. However, most studies address its effects in bulk soils in natural systems, with few focusing on its effects in the rhizosphere of plants. Predicting pH effects in the rhizosphere is an important step towards successful microbiome manipulation, aiming to increase crop production. Here, we modulated an acidic soil's pH to four different ranges (4.7, 5.2, 7.5 and 8.2), while correcting for fertility differences among ranges, thus isolating pH effects from other physicochemical characteristics. Then, two crops with distinct metabolisms (maize and bean) were cultivated in a greenhouse experiment and the effects of pH and cover crops on the rhizosphere bacteriome after 90 days explored through 16S rRNA gene sequencing, aiming to characterize pH effects on the rhizosphere of two different plants across this gradient. Alpha diversity indexes (OTU richness and Shannon index) were statistically different with pH but not crop species, with an interaction among factors. For beta diversity, both pH and crop species were significant modulators of community composition, without an interaction, but pH effects were 2.5 times bigger than those of plant species. Additionally, strong and significant positive correlations were observed between pH and Bacteroidetes and Deltaproteobacteria, while Actinobacteria, Planctomycetes and Acidobacteria were negatively correlated with pH. Regarding OTUs, 27 and 46 were correlated with pH in maize and bean's rhizosphere, respectively, while 11 were shared between them. Altogether, these results provide valuable information on the isolated effect of pH in the rhizosphere of important crop plants, aiding future microbiome manipulation studies. [ABSTRACT FROM AUTHOR]

In the no-tillage system in Brazil, grasses are commonly grown for grain production or soil cover in the soybean off-season with no or low nitrogen (N) fertilization rates. The soybean sowing in soil containing high amounts of grass straw can lead to mineral N temporary immobilization at the beginning of the crop cycle. Some farmers apply N fertilizers at soybean sowing, often combined with seed inoculation with Bradyrhizobium spp. to circumvent that limitation. The objective of this work was to evaluate the effects of N fertilization at soybean sowing cultivated after different off-season crops or after fallow on soybean yield and grain protein and oil concentrations. The field experiment installed in Londrina, Paraná, Brazil, lasted seven years. The treatments were plots unfertilized or fertilized with 30 kg ha−1 N at soybean sowing with five land uses in the off-season: (i) corn for grain production with N (80 kg ha−1) broadcasted, (ii) corn for grain production without N fertilization, (iii) wheat for grain production without N fertilization, (iv) ruzigrass (Urochoa ruziziensis) as a cover crop, and (v) unplanted fallow. Results showed no interaction between soybean N fertilization and off-season crops on any variable. Soybean N fertilization did not affect grain yield (mean of 4064 kg ha−1 without N and 4136 kg ha−1 with N fertilization) in any of the seven seasons, including when the yield average was higher than 4500 kg ha−1, which implies a high N demand for grain production. N applied at soybean sowing did not influence grain protein or oil concentration. Off-season cultivation of ruzigrass and wheat resulted in higher soybean yields (4354 and 4304 kg ha−1, respectively) than off-season cultivation of corn with or without N and fallow (4058, 3942, and 3843 kg ha−1, respectively). Soybean protein concentration (367 g kg−1) was highest after ruzigrass and lowest (354 g kg−1) after fallow. Soybean cultivated after N-fertilized corn yielded the maximum oil concentration (222 g kg−1) and rendered the minimum (216 g kg−1) after wheat. The results indicate that the mineral N application at soybean sowing was unnecessary, even in plots with high amounts of grass straw produced during the off-season. [ABSTRACT FROM AUTHOR]

Sustainable agricultural soil management practices are key to restore, maintain and improve soil health. The European Joint Programme for SOIL (EJP SOIL) has identified twelve main soil challenges in Europe. To assess the potential and eventually increase the adoption of soil‐improving management practices, it is necessary to know (i) the current levels of adoption of the practices, (ii) socio‐technical barriers influencing their adoption, and (iii) their bio‐physical limits. This study compiled an inventory of soil‐improving management practices relevant to European conditions, and used a survey among soil scientists to assess the levels of adoption of these practices in Europe. In total, 53 soil management practices were identified that address one or several of the soil challenges. The adoption of most practices was low or spatially heterogeneous across Europe, highlighting region‐specific limitations to sustainable soil management. Qualitative interviews were conducted to explore the importance of socio‐technical aspects of adoption. Using conservation agriculture as an example, factors that can hinder adoption included the availability of knowledge and adequate machinery, financial risks, and farming traditions. Through a modelling approach, 54% of arable land in Europe was found to be suitable for cover cropping, indicating that the adoption of soil management practices is frequently limited by climatic constraints. We propose a region‐specific approach that recognizes the importance of identifying and overcoming socio‐technical barriers, and by acknowledging bio‐physical limits that may be expanded by innovation. [ABSTRACT FROM AUTHOR]

Cover crops (CC) offer numerous benefits to agroecosystems, particularly in the realm of soil organic carbon (SOC) accrual and loss mitigation. However, uncertainties persist regarding the extent to which CCs, in co‐occurrence with environmental factors, influence SOC responses and associated C pools. We therefore performed a weighted meta‐analysis on the effects of CCs on the mineral‐associated organic carbon (MAOC), the particulate organic carbon (POC) and the microbial biomass carbon (MBC) pool compared to no CC cultivation in arable cropland. Our study summarized global research of comparable management, with a focus on climatic zones representative of Europe, such as arid, temperate and boreal climates. In this meta‐analysis, we included 71 independent studies from 61 articles published between 1990 and June 2023 in several scientific and grey literature databases. Sensitivity analysis was conducted and did not identify any significant publication bias. The results revealed that CCs had an overall statistically significant positive effect on SOC pools, increasing MAOC by 4.8% (95% CI: 0.6%–9.4%, n = 16), POC by 23.2% (95% CI: 13.9%–34.4%, n = 39) and MBC by 20.2% (95% CI: 11.7%–30.7%, n = 30) in the top soil, compared to no CC cultivation. Thereby, CCs feed into the stable as well as the more labile C pools. The effect of CCs on MAOC was dependent on soil clay content and initial SOC concentration, whereas POC was influenced by moderators such as CC peak biomass and experiment duration. For MBC, for example, clay content, crop rotation duration and tillage depth were identified as important drivers. Based on our results on the effects of CCs on SOC pools and significant moderators, we identified several research needs. A pressing need for additional experiments exploring the effects of CCs on SOC pools was found, with a particular focus on MAOC and POC. Further, we emphasize the necessity for conducting European studies spanning the north–south gradient. In conclusion, our results show that CC cultivation is a key strategy to promote C accrual in different SOC pools. Additionally, this meta‐analysis provides new insights into the state of knowledge regarding SOC pool changes influenced by CCs, offering quantitative summary results and shedding light on the sources of heterogeneity affecting these findings. [ABSTRACT FROM AUTHOR]

Conservation alternatives that include no-tillage (NT) and cover crops (CCs) reduce soil erosion in row-crop agroecosystems. However, little information is available about how these alternatives affect soil textural properties responsible for soil fertility. This study evaluated the soil particle size distribution and volumetric water content after three years of consistent management in a raised bed system. There were four treatment systems in a dryland maize/soybean rotation on a silt loam soil (Oxyaquic Fraglossudalfs) that included: NT + CCs, conventional tillage (CT) + CCs, CT + winter weeds, and CT + bare soil in winter in northwest Mississippi. The NT + CC system retained 62% more coarse sand in the furrow than the other systems (2.1% compared to 1.3%; p = 0.02). Regardless of the location, the NT + CC system (2.5%) retained 39% more fine sand than the CT + CC system (1.8%; p = 0.01), suggesting that coarse and fine sands were being trapped in furrows combining NT + CC systems, minimizing their off-site transport. In furrows, CCs increased soil volumetric water content by 47% compared to other winter covers. In beds, NT + CCs increased bed water contents by 20% compared to CT + CCs (17.1 to 14.3%; p < 0.01). Implementing conservation alternatives may promote the retention of sand fractions in silty loam soils that are important in supporting soil fertility and crop sustainability. [ABSTRACT FROM AUTHOR]

The composition of a soil microbial community that is associated with novel rotation crops could contribute to an increased yield of subsequent crops and is an important factor influencing the composition of the rhizosphere microbiome. However, the effect of alternative dryland crops on soil microbial community composition is not clear in the northern Great Plains (NGP). The objective of this study, therefore, was to evaluate the effects of the oilseed crops Ethiopian mustard (Brassica carinata A.) or camelina (Camelina sativa L.) or a 10-species forage/cover crop (CC) mix and fallow on soil biological health. Phospholipid fatty acid (PLFA) analysis was used to characterize the microbial community structure. The results showed that the total bacterial PLFA proportion was significantly higher in camelina and fallow compared to CCs and carinata, whereas the total fungal proportion was significantly higher under a CC mix compared to camelina and fallow. The fungal-to-bacterial ratio was significantly higher in CCs (0.130) and carinata (0.113) compared to fallow (0.088). Fungi are often considered a good indicator of soil health, while bacteria are crucial in soil functions. The changes in specific microbial communities due to crop-related alterations might play a key role in the yield of subsequent crops. This study provides valuable insights into the effect of oilseeds, CCs, and fallow on microbial communities. [ABSTRACT FROM AUTHOR]

Background and aims: Cover crops can increase nitrogen (N) retention in agroecosystems by taking up soil soluble N when the grain crop is absent. We examined how the combination of cover crops and variability in winter conditions can affect soil N retention and N transfer to the subsequent crop. Methods: We used 15N tracer to quantify how the presence of cover crops (both winter-hardy and winter-killed) modifies the recovery by a corn crop of soil soluble N added the previous fall, and we used snow removal to assess how increased freezing would alter 15N recovery. We predicted snow removal would decrease 15N recovery in corn, and this decrease would be highest for plots with winter-hardy cover crops, given they remain vulnerable to increased frost over winter. Results: Cover crops approximately doubled corn grain 15N recovery (up to 8% of the added 15N) relative to the treatment that lacked cover crops (4% of the added 15N). Snow removal reduced 15N recovery in corn grain, but this effect did not differ among cover crop treatments. 15N recovery in soil at the time of corn harvest was increased by cover crops, with retention as high as 40% of the added 15N tracer, compared to only 20% for soil in the control plots. Soil 15N recovery was not significantly reduced by snow removal. Conclusion: Although increased soil freezing reduced grain N recovery, cover crops increased soil N retention, which indicates decreased N losses to the surrounding environment, and the potential for increased contributions to grain N in future years. [ABSTRACT FROM AUTHOR]

Cover crops play a pivotal role in mitigating climate change by bolstering carbon sequestration through biomass production and soil integration. However, current methods for quantifying cover crop biomass lack spatial precision and objectivity. Thus, our research aimed to devise a remote-sensing-based approach to estimate cover crop biomass across various species and mixtures during fallow periods in France. Leveraging Sentinel-2 optical data and machine learning algorithms, we modeled biomass across 50 fields representative of France's diverse cropping practices and climate types. Initial tests using traditional empirical relationships between vegetation indices/spectral bands and dry biomass revealed challenges in accurately estimating biomass for mixed cover crop categories due to spectral interference from grasses and weeds, underscoring the complexity of modeling diverse agricultural conditions. To address this challenge, we compared several machine learning algorithms (Support Vector Machine, Random Forest, and eXtreme Gradient Boosting) using spectral bands and vegetation indices from the latest available image before sampling as input. Additionally, we developed an approach that incorporates dense optical time series of Sentinel-2 data, generated using a Radial Basis Function for interpolation. Our findings demonstrated that a Random Forest model trained with dense time series data during the cover crop development period yielded promising results, with an average R-squared (r2) value of 0.75 and root mean square error (RMSE) of 0.73 t·ha−1, surpassing results obtained from methods using single-image snapshots (r2 of 0.55). Moreover, our approach exhibited robustness in accounting for factors such as crop species diversity, varied climatic conditions, and the presence of weed vegetation—essential for approximating real-world conditions. Importantly, its applicability extends beyond France, holding potential for global scalability. The availability of data for model calibration across diverse regions and timeframes could facilitate broader application. [ABSTRACT FROM AUTHOR]

Excessive tillage reduces soil water storage and increases surface runoff. Cover crops can modify the effect of tillage on soil water dynamics, but limited information is available for the Mississippi River Alluvial Basin. This study was conducted to determine whether soil–water dynamics could be manipulated through conservation production systems affecting surface residue management. Effects of tillage (conventional tillage [CT] vs. no‐tillage [NT]) and cover cropping (no cover crop and Austrian pea [Pisum sativum L.] cover crop [CC]) on soil water balance during the CC season in sorghum (Sorghum bicolor L.) and cotton (Gossypium hirsutum L.) crops were modeled using the root zone water quality model for a site near Stoneville, MS, on "Commerce" silty‐loam soil. Capacitance sensors measured soil volumetric water content to 120 cm during CC growth in 2019 and 2020. Field calibration of sensors reduced root mean square error from 0.05 to 0.03 m3 m−3. Pooled across years, NT increased volumetric water content in the 0–40 and 40–120 soil layers by 8.5% and 6.8%, respectively, compared to CT. Regardless of the CC treatment and cropping system, NT reduced surface runoff by 24.5% over its conventional counterpart, while soil water storage increased from 2.35 to 5.23 cm within the 1.2‐m profile, resulting in a 17% increase in consumptive use of water (evapotranspiration). CC treatments did not impact soil water storage and consumptive water use. The results demonstrate that NT systems can affect water dynamics by increasing infiltration and soil water storage in the humid subtropical region of the United States. Core Ideas: No‐tillage reduced surface runoff and increased soil water storage in alluvial soil.Cover crop reduced runoff from no‐till plots but not from conventional tillage.Cover crop produced substantial biomass with minimal risk of depleting soil water.No‐tillage with cover cropping would improve soil water storage in the Mississippi River Basin. [ABSTRACT FROM AUTHOR]

Information on corn (Zea mays L.) residue removal and organic amendment additions to ameliorate removal effects on soil properties is limited. Thus, we compared impacts of corn residue removal at 59% and organic amendments (winter rye [Secale cereale L.]) cover crop and manure every other year at 24 Mg ha−1 on soil organic carbon (SOC) and physical properties after 10 years under irrigated no‐till continuous corn on a silt loam in the western US Corn Belt. We collected soil property data after 10 years and then compared it with earlier results from this experiment (3 and 6 years). Cover crop and manure amendments maintained SOC concentration, but no amelioration practice reduced SOC concentration (−15%) from 3 to 10 years when residues were annually removed in 0‐ to 5‐cm depth. Under residue retention, SOC concentration increased with time with largest increase (+41%) occurring under manure amelioration practice in the 0‐ to 5‐cm depth. Residue removal reduced soil wet aggregate stability by 34%, soil dry aggregate stability by 73%, bulk density by 6%, water content at −33 kPa matric potential by 14%, and plant available water by 17% after 10 years in the 0‐ to 5‐cm soil depth but did not affect infiltration rate. Cover crops increased wet aggregate stability (32%), but manure and cover crops had limited effects on other soil properties. Residue removal increased the susceptibility of the soil to erosion and reduced water retention and SOC after 3 years, but such effects were not fully offset by amendments. Core Ideas: Corn residue removal at 59% reduced soil wet and dry aggregate stability and water content at field capacity.Residue removal did not negatively affect soil bulk density, infiltration rate, and saturated hydraulic conductivity.Cover crops partially offset residue removal effects on soil organic carbon and soil wet aggregate stability.Manure partially offsets the negative effects of residue removal on soil organic carbon after 3 and 10 years. [ABSTRACT FROM AUTHOR]

Conservation agriculture and associated soil health practices potentially enhance soil resilience by improving the soil's physical, chemical, and biological properties and processes. This study assessed the impact of tillage (conventional tillage [CT] and no‐till [NT]); crop rotation: 2‐year corn (Zea mays L.)–soybean (Glycine max L.), 3‐year corn–soybean–oat (Avena sativa L.), and 4‐year corn–soybean–oat–wheat (Triticum aestivum L.)]; cover crops (cover crop [CC] and no cover crop [NC]); and drainage (tile drainage [TD] and without drainage [ND]) on soil organic matter (SOM), bulk density, wet aggregate stability (WAS), and field‐saturated hydraulic conductivity (Kfs). Soil samples were collected over 2 years apart from five depths (0–10, 10–20, 20–30, 30–60, and 60–90 cm) and analyzed for SOM, bulk density, and WAS. In‐situ infiltration tests were conducted in each plot to determine field‐saturated hydraulic conductivity. This study showed that NT practice significantly increased SOM by 5.4%, WAS by 7.7%, and bulk density by 6.7% within 0–10 cm soil profile but decreased Kfs by 47.6% compared to CT through increased bulk density in the topsoil. NT increased SOM for every soil depth and, similarly, increased WAS for every depth but only statistically significant increases occurred at 0–10 cm and 60–90 cm. Further, higher crop diversity decreased bulk density and increased WAS. Nine years of CC and six years of tile drainage practices had no significant effect on SOM, bulk density, WAS, and Kfs. Core Ideas: Long‐term no‐till (NT) has a significant impact on soil physical and hydraulic properties.NT increased soil bulk density, soil organic matter (SOM), and wet aggregate stability (WAS) by 6.7%, 5.4%, and 7.7%, respectively, for 0‐ to 10‐cm depth but decreased Kfs by 47.6% within profile than conventional tillage (CT).Compaction decreased at 0–10 cm in CT but increased within the 10–60 cm soil profile.NT with more diverse rotation and cover crop (CC) practices showed limited or no positive impact on Kfs for silt clay loam.CC and tile drainage(TD) had minimal impact on SOM, bulk density, WAS, and Kfs under silt clay loam in southeastern South Dakota. [ABSTRACT FROM AUTHOR]

Weeds have a significant impact on vegetable production worldwide. These intensive cropping systems feature frequent tillage, fertilization and irrigation, providing ideal growing conditions for crops as well as certain weeds. Integrated weed management (IWM) can reduce reliance on herbicides by encouraging a systems approach to weed management. Using insights from global research and industry literature, we investigated the effectiveness of prevailing weed control methods, and evaluated emerging management practices and technologies for ongoing research and adoption. Weed control relies primarily on a relatively narrow range of herbicides as well as frequent tillage. Herbicides have negative impacts on soil, water and human health, while tillage impacts soil quality and function. Intensive cropping on smaller plots facilitates IWM, relying on multiple strategies including hand weeding, mulches, cover crops and cultural methods (e.g., crop rotations, timing). New herbicide options are suggested as an industry priority but are constrained by the lack of new chemistry and potential herbicide resistance. Refinement and adoption of non‐herbicide and emerging precision control methods into farm IWM in vegetables is more likely to be sustainable. This review is relevant to advanced vegetable production systems globally, but also to smallholder vegetable production in developing economies. [ABSTRACT FROM AUTHOR]

Winter cover crops have been shown to promote the accumulation of microbial biomass carbon and nitrogen, enhance nutrient cycling, reduce erosion, improve ecosystem stability, etc. In the black soil area of Northeast China, Triticum aestivum L., Medicago sativa L., Vicia villosa Roth., Triticum aestivum L. and Medicago sativa L. mixed planting, Triticum aestivum L. and Vicia villosa Roth. mixed planting, and winter fallow fields (CK) were selected to investigate the effects of winter cover crops on soil total carbon and nitrogen and microbial biomass carbon and nitrogen. The results showed that (1) after seasonal freeze-thaw, the rate of change in SOC (−2.49~6.50%), TN (−1.54~5.44%), and C/N (−1.18~1.16%) was less than that in SMBC (−80.91~−58.33%), SMBN (−65.03~332.22%), and SMBC/SMBN (−45.52~−90.03%); (2) winter cover crops not only alleviated the negative effects of seasonal freeze-thaw, which reduces SMBC and qMBC, but also increased SMBN and qMBN; (3) there was an extremely significant (p < 0.01) positive correlation between SOC and TN, a significant (p < 0.05) negative correlation between SMBC and SMBN, and there was no significant correlation between SOC and SMBC or between TN and SMBN; (4) alkali-hydrolysable nitrogen had the greatest impact on SOC and TN, while the soil's saturation degree had the greatest impact on SMBC and SMBN; and (5) the Triticum aestivum L. monoculture was the most effective in conserving soil microbial carbon and nitrogen. In conclusion, winter cover crops can mitigate the reduction in soil microbial biomass carbon caused by seasonal freeze-thaw and also increase the soil microbial nitrogen content in the black soil region of Northeast China, of which Triticum aestivum L. monoculture showed the best performance. [ABSTRACT FROM AUTHOR]

Understanding the stoichiometry of extracellular enzymes in soil, particularly in relation to nutrient acquisition (e.g., carbon, nitrogen, phosphorus), provides valuable insights into microorganisms' resource requirements. This study investigates the metabolic constraints of soil microorganisms in response to different growth stages of apple trees under various soil management practices. A 14-year long-term experiment with a split-plot design was conducted, where the main plots received different cover crop treatments (bare vs. cover crop), and subplots were subjected to four fertilizer treatments (CK, M, NPK, MNPK). The significant main and interactive effects of cover crops, fertilizer treatment, and growth period on soil nutrients were observed (p < 0.001). Both cover crop and fertilizer treatments significantly increased the soil organic matter content, with implications for orchard resilience to drought. However, the cover factor alone did not notably influence soil carbon–nitrogen ratios or microbial communities. Microbial carbon limitations were driven by soil water dynamics and microbial biomass, while microbial phosphorus limitations were closely linked to total nitrogen levels. The results underscore the combination of cover crops and MNPK fertilizer-enhanced soil nutrient levels and enzyme activities, mitigating microbial carbon and phosphorus limitations. These findings suggest practical strategies for optimizing fertilization practices to improve soil fertility and address nutrient constraints in orchard ecosystems. [ABSTRACT FROM AUTHOR]

Traditional rice production is often reliant on the unsustainable practice of utilizing intensive inputs in monoculture cropping systems. Alternatives fallow cover cropping and rice–fish coculture (RFC) offer promising solutions. However, the potential of fallow cover cropping in RFC remains underexplored, and its impact on soil microbes is poorly understood. In this study, assessments of soil–plant–microbe interactions were conducted across three cover cropping systems: Chinese milk vetch (Astragalus sinicus L.) single cropping (CM), Rapeseed (Brassica napus L.) single cropping (RP), and a combination of Chinese milk vetch and rapeseed intercropping (CM_RP). These systems were evaluated with and without nitrogen (N) addition, encompassing both the RFC and rice monoculture (RMC) systems. The findings indicate a notable increase in soil microbial biomass nitrogen (MBN) with CM. Soil microbial biomass carbon (MBC), influenced more by N-fertilizer than crop species, decreased with N addition. In the RFC system, the soil bacterial co-occurrence network exhibited more connections, yet negative links increased. CM_RP displayed similarities to CM without N but shifted closer to RP with N addition. N addition in intercropping significantly increased the root–shoot ratio (R/S) of A. sinicus, associated with decreased aboveground biomass and total root length. Compared to RMC, RFC with N addition reduced the relative abundance of Anaerolineaceae in CM while increasing Bacillus and Pontibacter across cover cropping systems. Overall, with N addition, both RFC and RMC showed decreased soil bacterial diversity indices. Changes in soil bacterial diversity correlated significantly with soil MBC, MBN, and plant R/S. Continuous fallow cover cropping altered soil microbial biomass and affected cover crop biomass distribution, impacting bacterial composition in paddy soil. These results shed light on how bacterial communities respond to N addition and fallow cover cropping in RFC and RMC systems, offering insights for sustainable nutrient management in paddy systems. [ABSTRACT FROM AUTHOR]

Nitrous oxide (N2O) exacerbates the greenhouse effect and thus global warming. Agricultural management practices, especially the use of nitrogen (N) fertilizers and irrigation, increase soil N2O emissions. As a vital sector of global agriculture, specialty crop systems usually require intensive input and management. However, soil N2O emissions from global specialty crop systems have not been comprehensively evaluated. Here, we synthesized 1137 observations from 114 published studies, conducted a meta‐analysis to evaluate the effects of agricultural management and environmental factors on soil N2O emissions, and estimated global soil N2O emissions from specialty crop systems. The estimated global N2O emission from specialty crop soils was 1.5 Tg N2O‐N year−1, ranging from 0.5 to 4.5 Tg N2O‐N year−1. Globally, soil N2O emissions exponentially increased with N fertilizer rates. The effect size of N fertilizer on soil N2O emissions generally increased with mean annual temperature, mean annual precipitation, and soil organic carbon concentration but decreased with soil pH. Global climate change will further intensify the effect of N fertilizer on soil N2O emissions. Drip irrigation, fertigation, and reduced tillage can be used as essential strategies to reduce soil N2O emissions and increase crop yields. Deficit irrigation and non‐legume cover crop can reduce soil N2O emissions but may also lower crop yields. Biochar may have a relatively limited effect on reducing soil N2O emissions but be effective in increasing crop yields. Our study points toward effective management strategies that have substantial potential for reducing N2O emissions from global agricultural soils. [ABSTRACT FROM AUTHOR]

Cultivated peatland (Histosol) in Southern Québec (Canada) is a rapidly declining non‐renewable resource used to grow most Canadian lettuce (Lactuca sativa L., Asteraceae). Rolled‐rye (Secale cereale L., Poaceae) cover crop is one of the conservation practices proposed to reach a more sustainable lettuce production, but the overall impact on the agroecosystem remains poorly studied in Histosols. We assessed multiple effects of rolled‐rye cover crop on the trophic chain associated with the lettuce aphid, Nasonovia ribisnigri (Mosley) (Hemiptera: Aphididae), a major pest of lettuce. During one growing season and through two consecutive lettuce crops, we monitored in situ the impacts of rolled‐rye cover crop on insect fauna and lettuce quality. We used visual scouting and yellow pan traps to assess plant colonization by N. ribisnigri, its natural enemies, and alternative prey. Exclusion cage experiments were also conducted to measure aphid fitness and population growth. Under greenhouse conditions, following cover crop removal, we examined potential lingering effects of rye within the soil on lettuce plants and N. ribisnigri. In situ experiments showed that rolled‐rye cover crop has the potential to inhibit N. ribisnigri field colonization and recruit natural enemies and alternative prey in the first lettuce crop. Rye also reduced aphid fitness as well as lettuce foliar amino acid concentration and weight. For the second lettuce crop, an almost 50% reduction in N. ribisnigri abundance was observed with the use of rolled‐rye cover crop. In greenhouse experiments, no persistent effect of rye was observed on the quality of lettuce grown with soil collected under a cover crop, nor on the fitness of aphids inoculated on these lettuces. This study highlights the diversity of trophic effects rolled‐rye cover crop may have on lettuce production in Histosols and the potential of rolled‐rye cover crop as a cultural practice to reduce aphid populations. Mechanisms at play while underlining agronomic challenges regarding proper rye termination must be further explored to maintain high‐performing lettuce yields. [ABSTRACT FROM AUTHOR]

U.S. agricultural producers are increasingly able to participate in private voluntary carbon initiatives that compensate their efforts to sequester CO2, reduce GHG emissions, and provide ecosystem services through eligible conservation practices. This study examines the potential effects of alternative private payment regimes (per practice vs. per output), prices paid to farmers relative to out-of-pocket costs (low vs. high), and the availability of information on CO2 sequestration (limited vs. full), on the adoption of cover crops and no-till in the United States, the resulting CO2 sequestration, and changes in farmers' net returns. The analysis relies on a highly stylized model of heterogeneous farms calibrated with county-level agronomic data, and simulated for current estimates of GHG impacts of cover crop planting and no-till under different scenarios. Our results indicate that agricultural carbon markets can be profitable for U.S. farmers, although with substantial geographic variability, and that annual carbon sequestration could range between 17 and 75 million mtCO2e. Payments per output would incentivize higher carbon sequestration than payments per practice, but the former regime would be less favored by farmers as a unified group than the latter (due to lower aggregate net returns). However, if operators of farms with high carbon sequestration potential could decide the payment regime to be implemented, they would choose the payment per output regime (due to higher net returns per enrolled hectare). Total projected net changes in GHGs under payments per practice, based solely on county-average net GHG effects of cover crops and no-till, over-estimate actual total GHG sequestration (based on the entire distribution of net effects by county) by 2.1 and 14.2 million mtCO2e, or 18% and 21%, respectively. [ABSTRACT FROM AUTHOR]

Background: Rye (Secale cereale L.) is a cereal crop highly tolerant to environmental stresses, including abiotic and biotic stresses (e.g., fungal diseases). Among these fungal diseases, leaf rust (LR) is a major threat to rye production. Despite extensive research, the genetic basis of the rye immune response to LR remains unclear. Results: An RNA-seq analysis was conducted to examine the immune response of three unrelated rye inbred lines (D33, D39, and L318) infected with compatible and incompatible Puccinia recondita f. sp. secalis (Prs) isolates. In total, 877 unique differentially expressed genes (DEGs) were identified at 20 and 36 h post-treatment (hpt). Most of the DEGs were up-regulated. Two lines (D39 and L318) had more up-regulated genes than down-regulated genes, whereas the opposite trend was observed for line D33. The functional classification of the DEGs helped identify the largest gene groups regulated by LR. Notably, these groups included several DEGs encoding cytochrome P450, receptor-like kinases, methylesterases, pathogenesis-related protein-1, xyloglucan endotransglucosylases/hydrolases, and peroxidases. The metabolomic response was highly conserved among the genotypes, with line D33 displaying the most genotype-specific changes in secondary metabolites. The effect of pathogen compatibility on metabolomic changes was less than the effects of the time-points and genotypes. Accordingly, the secondary metabolome of rye is altered by the recognition of the pathogen rather than by a successful infection. The results of the enrichment analysis of the DEGs and differentially accumulated metabolites (DAMs) reflected the involvement of phenylpropanoid and diterpenoid biosynthesis as well as thiamine metabolism in the rye immune response. Conclusion: Our work provides novel insights into the genetic and metabolic responses of rye to LR. Numerous immune response-related DEGs and DAMs were identified, thereby clarifying the mechanisms underlying the rye response to compatible and incompatible Prs isolates during the early stages of LR development. The integration of transcriptomic and metabolomic analyses elucidated the contributions of phenylpropanoid biosynthesis and flavonoid pathways to the rye immune response to Prs. This combined analysis of omics data provides valuable insights relevant for future research conducted to enhance rye resistance to LR. [ABSTRACT FROM AUTHOR]

Purpose: Cover crops (CC) may increase root growth of the following main crop by improving the soil structure, however, the extent of this effect might depend on the CC species. This study aims at quantifying the effects of different CCs on sugar beet (SB; Beta vulgaris L.) fibrous roots and plant growth. Methods: Two field trials were conducted near Göttingen, Central Germany, with SB after four CC treatments: fallow, oil radish, saia oat, and spring vetch, differing in biomass. SB root length density and biomass was analyzed to 60 cm soil depth in July, around 100 days after sowing. From June on, plants were sampled monthly to determine leaf and taproot biomass. CC biomass and SB residues were further analyzed for carbon content. Results: SB root length density in 0–20 cm soil depth was increased by the CCs, particularly radish and oat, while in lower depths only non-significant differences were found. Differences between the CC treatments regarding SB leaf and taproot biomass were site-specific with increases in SB biomass after CCs at a site with high N supply, yet no effects on sugar yield were found for either site. Carbon input into the soil was significantly increased through CC cultivation by 47 to 85%. Conclusion: CCs with different properties improved fibrous root and overall plant growth of SB to a different extent at sites with contrasting conditions. Future studies under diverse environmental conditions are needed to fully assess the potential benefits of CCs on following SB growth. [ABSTRACT FROM AUTHOR]

Rationale and Purpose: Adding multispecies cover crop (CC) mixtures could diversify the current simplified crop rotations and enhance soil health more than monoculture CCs. Further, CC mixtures with diverse plant species could adapt better to changing climatic and environmental conditions than monoculture CCs. However, our current understanding of the soil benefits of CC mixtures is still limited. This review discussed whether CC mixtures are better than monoculture CCs to improve soil physical health. Methods: All studies published up to May 25, 2023 comparing soil physical properties between CC mixtures and their constituents grown as monocultures were searched in the available databases. To avoid potential sampling bias, only studies that compared mixtures against all its constituents grown alone were discussed. Results: Cover crop mixture studies on soil physical properties were relatively few. Mixtures did not reduce soil bulk density in 83% of cases, penetration resistance in 75%, wet aggregate stability in 67%, and dry aggregate stability and saturated hydraulic conductivity in 100% compared with monoculture CCs. Mixtures had inconsistent effects on water infiltration and plant available water. The number of CC species in the mixture and management duration do not differently affect mixture impacts. The limited or no differences in soil physical properties between mixtures and monocultures could be due to the similarities in CC biomass production and soil C between these two systems. Conclusion: Cover crop mixtures do not enhance soil physical properties relative to monoculture CCs in most cases. However, the few cases where mixtures outperformed monocultures suggest soil benefits of mixtures should be evaluated on a site-specific basis. More long-term (> 10 yr) data are needed for more definitive conclusions. Highlight: Cover crop mixtures do not generally improve soil physical health more than monoculture CCs. [ABSTRACT FROM AUTHOR]

The development of civilization is related to an increase in energy demand, while its production is still based mainly on fossil fuels. The release of carbon into the environment, which disturbs the balance of the global system, is the consequence of using these fuels. One possible way to reduce the carbon footprint of the energy sector is the widespread use of cover crops' biomass for energy production. The aim of this paper is to critically review the knowledge on the dissemination of catch and cover crops' cultivation in different regions of the world, and the yield, chemical composition and biomethane potential of their biomass. Additionally, the environmental benefits, as well as the challenges and opportunities associated with this biomass use in the energy sector, are considered. The review showed that the aboveground biomass of cover and catch crops is a valuable source for the production of bioenergy in biogas plants. However, the key role of these crops is to prevent soil degradation. Therefore, changes in biomass target use must be preceded by a multi-aspect analysis that allows their impact on the environment to be assessed. [ABSTRACT FROM AUTHOR]

Simple Summary: Interest is increasing in grazing winter canola as an alternative crop in winter wheat rotations in the Southern High Plains of the USA and similar environments. In this study, winter cereal rye and winter canola pastures (forage) were compared for two winter growing seasons to determine the relative effect of pasture type on beef cattle performance, along with the effect of grazing on canola grain production. Canola grain yields were reduced by 25% when canola was grazed for approximately one month after grazing was initiated, but before the onset of rapid regrowth in spring. No differences existed for forage mass, nutritive value, or animal performance, although forage mineral composition of canola could be a concern. Grazing winter canola as a dual-purpose crop in semiarid environments is feasible when proper grazing management is applied; a 20–25% reduction in grain yield should be anticipated, but expect animal gains to offset that loss. Interest is increasing in grazing winter canola (Brassica napus) as an alternative crop in winter wheat (Triticum aestivum) rotations in the Southern High Plains (SHP) of the USA and similar environments. In this stidy, winter cereal rye (Secale cereale) and winter canola pastures (forage) were compared for two winter growing seasons at New Mexico State University's Rex E. Kirksey Agricultural Science Center at Tucumcari, NM, USA, to determine the relative effect of pasture type on late-gestation beef cows and growing yearling cattle, along with the effect of grazing on canola grain production. Canola grain yields were reduced by 25% when canola was grazed until removal approximately one month after grazing was initiated, but before the onset of rapid regrowth after winter (641 vs. 486 kg grain ha−1 for never grazed or grazed canola, respectively, p < 0.0256). No differences existed for forage mass, nutritive value, or animal performance, although forage mineral composition of canola could be a concern. Grazing winter canola as a dual-purpose crop in the SHP and similar environments is feasible when proper grazing management is applied; producers should anticipate a 20–25% reduction in grain yield, but expect animal gains to offset that loss. [ABSTRACT FROM AUTHOR]

Summary: The use of non-host cover crops can be a viable strategy for managing soybean cyst nematode (SCN) Heterodera glycines. Cover crops may affect SCN biology and reduce populations by acting as trap crops that promote the hatching and/or penetration by second-stage juveniles (J2) without supporting their development. Two growth chamber experiments were conducted to assess ten cover crops for their impacts on SCN hatching and penetration into the roots. For each experiment, with four replications per treatment, crops were planted in naturally-infested soil in two separate sets to be harvested 15 and 30 days after planting (DAP). SCN susceptible soybean 'Barnes' and non-planted natural soil (fallow) were used as controls. Faba bean 'Petite', a non-host of SCN, induced the greatest hatching among the cover crops and was statistically similar to soybean. Winter rye 'ND Dylan' also induced significant hatching compared to fallow. Root staining revealed that the highest number of J2 penetrated the faba bean roots at 15 DAP, followed by soybean and winter rye. While J2 penetrated all tested crops, they completed their development to become adult females only in soybean and turnip. Soybean cyst nematode development to adult females did not occur in faba bean, and the number of SCN inside the faba bean roots 30 DAP was significantly lower than at 15 DAP and also lower than in soybean. These results suggest that the faba bean affects SCN biology and has the greatest potential to act as a trap crop for managing SCN. [ABSTRACT FROM AUTHOR]

The use of cover crops can improve the environmental sustainability of intensive cropping systems. A five-year field trial was undertaken to evaluate the effect of multi-season cover cropping on weed suppression within a no-till spring-planted maize system in the Waikato region in New Zealand. Five cover crop treatments were compared: gland clover (Trifolium glanduliferum Boiss.); faba bean (Vicia faba L); oats (Avena sativa L.); and Italian ryegrass (Lolium multiflorum Lam.), and winter fallow. The results demonstrated that in this system, herbicide treatments can be reduced to one application to terminate the winter cover crop and a single maize post-emergence application, thus reducing selection pressure for herbicide-resistance, without any loss in silage or grain production. Furthermore, a legume-based cover crop gave higher yields than the grass cover-crops and reduced the damage by the maize and grass pest cosmopolitan armyworm (Mythimna separata Walker). The build-up of crop residue over time was detrimental to the establishment of the small-seeded clover and ryegrass cover crops but good weed suppression and grain yields were achieved in the final season by replacing them respectively with the larger seeded woolly pod vetch (Vicia eriocarpa (Hausskn.) Halácsy) and a blue lupin (Lupinus angustifolius L.)/ mustard (Sinapis alba L.) mix. [ABSTRACT FROM AUTHOR]

While cover crop residue (CR) incorporation offsets soil organic C (SOC) losses caused by plastic-film mulching (PFM), the microbial modulators and mechanisms of SOC accumulation remain poorly understood. Using functional gene microarray, soil enzyme activities, and soil density fractionation approaches, we investigated the mechanism, by incorporating CR (13.0 and 9 Mg ha−1 on a dry weight basis) under PFM in organic maize cropping systems, spanning 2 consecutive years. Compared to no-mulching, PFM without CR amendment significantly decreased SOC stock by 23%, corresponding to an increase in CO2 efflux by 74%, a decrease in light fraction C (LFOC) and heavy fraction C (HFOC) by 13 and 11%, respectively, and an increase in relative abundances of labile as well as recalcitrant C-degrading genes and related soil enzyme activities. However, PFM with CR amendment reduced the SOC stock loss to 11%, corresponding to 36% increase in CO2 efflux, 22% decrease in LFOC but 12% increase in HFOC, and an increase in relative abundances of labile C-degrading genes and related soil enzyme activities but a decrease in relative abundances of recalcitrant C-degrading genes and related soil enzyme activities. Our results, based on microbial functional genes, suggest that reduced degradation of recalcitrant C was responsible for increased mineral-associated C and thus SOC accumulation under PFM in organically cultivated maize. [ABSTRACT FROM AUTHOR]

Different soybean cultivars (Williams 82, Union, Jindou 21, Long Huang 1, Long Huang 2) were exposed to drying soil, to investigate whether endogenous abscisic acid (ABA) concentrations and leaf water relations regulated stomatal behaviour. We measured ABA concentrations in xylem and tissue of the first and second trifoliate leaves respectively; stomatal conductance (gs) and leaf water potential (Ψleaf) in both leaves; and water content in soil. Cultivar variation in leaf area and gs caused different rates of soil drying, but gs and Ψleaf declined similarly with soil drying in all cultivars. Variation in leaf xylem ABA concentration better explained stomatal responses than foliar ABA concentration in some cultivars, and was highly correlated with stomatal conductance. Xylem ABA concentration in well-watered soil was highest in Union, and in drying soil was lowest in Jindou 21 and Long Huang 2, although the latter had the highest foliar ABA concentrations. Jindou 21 accumulated lower xylem ABA concentrations than other cultivars as soil moisture or Ψleaf decreased, but its stomatal sensitivity to xylem ABA was greater. Because cultivars varied in both ABA accumulation and stomatal sensitivity to ABA, but had similar stomatal sensitivity to Ψleaf, leaf water relations seem more important in regulating stomatal closure of soybean. [ABSTRACT FROM AUTHOR]