Winter Cover Crops Research Articles

Legume Cover Crop Alleviates the Negative Impact of No-Till on Tomato Productivity in a Mediterranean Organic Cropping System

The ecosystem services a cover crop (CC) provides depend enormously on species choice and tillage system. Here, we evaluated the impact of (a) three winter CCs—rye (Secale cereale L.) and squarrose clover (Trifolium squarrosum L.) monocultures and their mixture, and (b) two tillage systems—roller-crimping of CC residue as dead mulch for no-till (NT) systems and incorporating CC residue into the soil as green manure for conventional tillage (CT) systems—on the performance of organic processing tomato, i.e., plant growth, nutrient accumulation, fruit yield, and weed biomass. The assessments took place over two years in field experiments conducted under Mediterranean conditions. At the termination time, rye and mixture were the most productive and the best weed-suppressive CCs. During tomato growing season, squarrose clover regardless of tillage system stimulated tomato growth, Nitrogen content and uptake, and the yield relative to the other cover crops. Nevertheless, NT generally impaired the tomato nutritional status and increased weed biomass compared to CT despite some potential weed control by cover crops. These two aspects caused a significant drop in tomato yield in all NT systems. The results suggested that, despite the multiple benefits the compared CCs can offer in Mediterranean agroecosystems, legume CCs could be the key to developing feasible organic vegetable no-till systems.

Residual biomass quality index: a tool for conservation agriculture

ABSTRACTOne of the pillars of a no-tillage system is the addition of adequate amounts of residue to keep the soil continuously covered. Cover crops are a tool for supplying the demand for the permanence of residues on the soil surface and releasing nutrients to the soil. However, there is no index that relates these two factors and can reconcile the maximum permanence of crop residues in the soil with the maximum N supply via N mineralization of such residues. This study aimed to assess the effect of different cover crops on the decomposition rate of residues and N release, using the residual biomass quality index (RBQI) to evaluate cover crop systems. The study was conducted in a long-term experiment in a Latossolo Vermelho (Ferralsol, Oxisol) under no-tillage in the two agricultural years 2017/18 and 2018/19. The experiment was in a split-plot factorial scheme with eight winter cover crops and three N rates in randomized blocks with three replications. The cover crop systems were black oat (O), common vetch (V), forage radish (R), white lupine, rye, annual ryegrass, oat + vetch (O+V), and oat + vetch + radish (O+V+R). The N rates applied to the corn in succession were 0, 90, and 180 kg ha-1. The decomposition rate, remaining dry mass (RDM) on the soil surface, N release rate, and N accumulated release (NAR) were assessed using litterbags. Considering NAR and RDM evaluated for up to 105 days, the N release index (NRI) and remaining dry mass index (RDMI) were determined, and the residual biomass quality index (RBQI) was obtained using the product of these variables. The consortia O+V+R and O+V resulted in a decomposition rate and N release rate closer to the rates observed for oats and rye. The NAR was similar to that observed for Fabaceae species, and the RDM was similar or superior to that found for black oat. With these characteristics, the systems in the O+V+R and O+V consortia presented the highest values of RBQI, ranging from 0.61 to 0.90, indicating that RBQI is a potential indicator for choosing cover crop systems that promote greater sustainability of the no-tillage system. The use of N fertilizer in corn did not change the rates of decomposition and N release from the residues of cover crops.

Managing cover crop C:N ratio and subsurface‐banded poultry litter rate for optimal corn yields

AbstractCover crops can be used to provide some of the nitrogen (N) needs of a cash crop to complement mineral fertilizers or manure, but there has yet been limited work to describe corn (Zea mays L.) yield as a function of cover crop quality and N inputs. We investigated the response of corn yield to gradients of both preceding cover crop C:N ratio and poultry litter (PL) application rates in Beltsville, MD during 2012–2014. To achieve different C:N ratios of the cover crops, hairy vetch (Vicia villosa Roth. "Groff") and cereal rye (Secale cereale L. "Aroostook") were seeded in a replacement series of six seeding rate proportions, resulting in shoot C:N ratios of 9.2:1 to 152:1 across years. For each hairy vetch/cereal rye sown proportions, PL was side‐dressed at corn V5–V8 stage in subsurface bands (SSB) at four targeted rates: Zero, P‐based (67 kg plant available nitrogen [PAN] ha−1), N‐based (135 kg PAN ha−1), and excess N and P (269 kg PAN ha−1). We found that corn yield followed a linear‐plateau relationship across these two dimensions. Within the linear region, each unit increase in log‐scaled cover crop C:N ratio resulted in a yield decrease of 2.56 ± 0.26 Mg ha−1 at a given rate of SSB PL. To optimize corn yields, we describe a model where each unit increase in log‐scaled cover crop C:N ratio required an additional 45.9 ± 6.22 kg PAN ha−1 from SSB PL. Yields following winter fallow were typically intermediate to the range of yields observed following the gradient of cover crop C:N ratios. We did not find significant differences in corn yield responses when comparing SSB PL to at‐planting incorporated or broadcast PL; we also found no significant differences between SSB PL and surface‐banded urea ammonium nitrate. Taken together, our approach of modeling yield response across two dimensions can be widely used to guide adaptive N management in subsequent cash crops following winter cover crops, thereby balancing both economic and environmental objectives in cover crop‐based cropping systems.

Winter Rye Cover Crop Seeding Rate and Termination Timing Effects on Cover Crop Biomass and Quality

ABSTRACT Winter rye (Secale cereale L.) biomass and chemical composition influences decomposition rates, nutrient cycling and effects on cash crop growth. Management that maintains rye biomass while lowering carbon (C) to nitrogen (N) ratios and concentrations of structural carbohydrates including hemicellulose, cellulose, and lignin could maintain some ecosystem services while accelerating nutrient cycling. Two independent studies examined (1) five rye seeding rates ranging from 0 to 90 kg ha−1 and (2) five termination dates ranging from April 19 to May 31 (585 to 1084 growing degree days) to understand management induced relationships between rye biomass, nutrient concentrations, and composition of hemicellulose, cellulose, and lignin. Rye biomass increased at seeding rates of 90 kg ha−1 as compared to the 22–67 kg ha−1 seeding rates while trends toward higher plant structural components were observed as seeding rate increased. Rye biomass accumulated rapidly beyond 819 (May 13) growing degree days while increasing rye C:N ratio and concentrations of hemicellulose and cellulose. Rye C:N ratio was strongly correlated to rye biomass (R2 = 0.80, p < .001) with a C:N ratio of 25 associated with 2000 kg ha−1 of rye biomass. Changes in rye residue quality were strongly influenced by biomass accumulation with delaying termination most significantly driving biomass changes. Trends toward lower C:N ratios and concentrations of structural carbohydrates were seen at the 22–67 kg ha−1 seeding rates even without differences in biomass suggesting lower seeding rates could cycle nutrients quicker without limiting biomass production potential.

An integrated weed management approach in tomato using soil steaming, mulching, and winter cover crops

One of the most significant yield losses in tomato (Solanum lycopersicum L.) is due to weeds. Yellow and purple nutsedge, large crabgrass, and Palmer amaranth are the most troublesome weed species in tomato production throughout the southeastern United States. This study aimed to determine the impact of soil steaming, plastic mulching, and cover crops on weed suppression, tomato height, and fruit yield. The cover crops used were hairy vetch (Vicia villosa), crimson clover (Trifolium incarnatum), and cereal rye (Secale cereale). The study was conducted at the Mississippi State University Truck Crops Experiment Station in Crystal Springs, Mississippi, USA. The experiment used a completely randomized block design with three fall cover crop treatments, including fallow, and each was replicated three times and repeated in two years. Each plot was broadcasted with a mixture of yellow nutsedge (Cyperus esculentus L.), large crabgrass (Digitaria sanguinalis L.), barnyardgrass (Echinochloa crus-galli), and Palmer amaranth [Amaranthus palmeri (S.) Watson] at a density of 20 plants m-2 for each weed species. Two days after sowing the weed seeds, the soil surface was steamed according to its assigned treatment until it reached 61°C for either 0, 5, or 20 min. After steaming, drip irrigation tubing was laid on each row, and covered by black, 0.0254-mm plastic mulch. Data were recorded in both years, including weed cover, plant height, and fruit yield. The lowest weed cover was observed at 5 min of soil steaming in mulched treatment, and the highest cover was noted at 0 min of soil steaming in the absence of mulching. Yellow nutsedge was the dominant weed species, even under steam and mulch treatments. The use of cover crops did not show a difference compared to fallow treatments. However, hairy vetch showed the lowest weed cover, followed by crimson clover. Tomato plants in steamed soil were up to 13 cm taller than those in unsteamed soils. Additionally, steaming at 5 or 20 min in combination with plastic mulch increased the marketable and cull yield. Soil steaming and mulching increased tomato plant height and yield while decreasing weed population and can, therefore, be effectively incorporated into an integrated weed management program in tomato.

Featured collection introduction: Water resources planning and management under changing conditions—Experience of Illinois

Pioneering work by John Stall on hydraulic geometries of streams and rivers was completed in the 1960s Water and Atmospheric Research Monitoring (WARM) program at the ISWS expanded data collection to define the environmental and socio-economic impacts of weather and climate impacts, including: The ISWS, along with the Illinois Natural History Survey (est. 1861) and Illinois State Geological Survey (est. 1905), were transferred out of the University of Illinois in 1917 to be administered by the Illinois Department of Registration and Education, eventually being transferred to the Illinois Department of Energy and Natural Resources and then to a new Illinois Department of Natural Resources. In 2008, the Scientific Surveys came home to where it all started, the University of Illinois, under the umbrella of the Prairie Research Institute with the addition of the Illinois Sustainability and Technology Center and Illinois State Archeological Survey. Together, the Prairie Research Institute has over 800 scientists, technicians, post-docs, research affiliates, visiting scholars, students, and administrative support staff, conducting transformative science that benefits the people, economy, and environment of Illinois, the nation, and the world. From their inception, the Scientific Surveys have always been located on the University of Illinois campus and continues to capitalize on the mutual benefits of collaboration with faculty and staff. The papers presented in this special issue marking the 125th anniversary founding of the ISWS are but a representation of the current contributions and research being conducted by ISWS scientists and colleagues, aiming to demonstrate what Illinois experiences in water resources planning and management under changing conditions, especially changing climate. They build on water supply planning legacy by incorporating future demands and climate uncertainties in Illinois, including the major updating of Illinois precipitation frequency standards. The theme of understanding uncertainties and bias continues in evaluating groundwater static head measurements to understand water-level variability. Of course, projecting climate change impacts is paramount to many water resource issues and authors discuss which climate ensemble approaches produce less uncertain climate model outputs. Nutrient losses in US agricultural lands are an issue not only for loss of crop production but downstream impacts. Winter cover crops have much promise for reducing nitrate, phosphorus, and sediment loads. Authors present possible detrimental impacts on storage volumes for downstream reservoirs in drought years. An Illinois River watershed analysis presents evidence that spatial and temporal shift in phosphorus loading affects recent increases in phosphorus despite point and nonpoint source efforts. The ISWS has long-term datasets which contributed to improved model calibration to capture chloride accumulation in shallow aquifers. Reservoirs serve populations and industry so understanding outflows from them is important for water resource planning and management. Comparing performance of three machine learning models shows promise for simulating reservoir outflow. Finally, colleagues in Illinois and China test a theoretical framework to better understand bivariate return periods of hydrological events, which is important for design criteria of hydraulic structures. The ISWS continues to evolve and adjust research needs, as demonstrated by the first 125 years, and look forward to providing science-based information to societies in the next 125 years. For further reading on ISWS history, the following publications are recommended:

Towards efficient N cycling in intensive maize: role of cover crops and application methods of digestate liquid fraction

AbstractDigestate, a by‐product of biogas production, is widely recognized as a promising renewable nitrogen (N) source with high potential to replace synthetic fertilizers. Yet, inefficient digestate use can lead to pollutant N losses as ammonia (NH3) volatilization, nitrous oxide (N2O) emissions and nitrate () leaching. Cover crops (CCs) may reduce some of these losses and recycle the N back into the soil after incorporation, but the effect on the N balance depends on the CC species. In a one‐year field study, we tested two application methods (i.e., surface broadcasting, BDC; and shallow injection, INJ) of the liquid fraction of separated co‐digested cattle slurry (digestate liquid fraction [DLF]), combined with different winter cover crop (CC) options (i.e., rye, white mustard or bare fallow), as starter fertilizer for maize. Later, side‐dressing with urea was required to fulfil maize N‐requirements. We tested treatment effects on yield, N‐uptake, N‐use efficiency parameters, and N‐losses in the form of N2O emissions and leaching. CC development and biomass production were strongly affected by their contrasting frost tolerance, with spring‐regrowth for rye, while mustard was winter killed. After the CCs, injection of DLF increased N2O emissions significantly compared with BDC (emission factor of 2.69% vs. 1.66%). Nitrous oxide emissions accounted for a small part (11%–13%) of the overall yield‐scaled N losses (0.46–0.97 kg N Mg grain−1). The adoption of CCs reduced fall leaching, being 51% and 64% lower for mustard and rye than under bare soil. In addition, rye reduced leaching during spring and summer after termination by promoting N immobilization, thus leading to −57% lower annual leaching losses compared with mustard. DLF application method modified N‐loss pathways, but not the cumulative yield‐scaled N losses. Overall, these insights contribute to inform an evidence‐based design of cropping systems in which nutrients are recycled more efficiently.

Balancing Tradeoffs in Climate-Smart Agriculture: Will Selling Carbon Credits Offset Potential Losses in the Net Yield Income of Small-Scale Soybean (Glycine max L.) Producers in the Mid-Southern United States?

There is a need to achieve sustainable agricultural production to secure food, fiber, and fuel for a growing global population. Climate-smart (CS) actions (no-till and cover crops) can reduce carbon emissions and promote soil organic carbon (SOC) storage. Contemporary voluntary carbon markets provide producers with a monetary incentive to adopt CS actions. However, SOC–yield dynamics under CS actions are not well known, making it difficult for producers to judge whether additional income from carbon credits will offset potential losses to yield income. We designed a SOC–yield framework that captures SOC–yield–income dynamics under traditional (reduced tillage, no cover crops) and CS actions. Using a modified structured decision-making approach, we applied the framework to a case study in which producers aim to increase income by selling carbon credits after adopting CS actions. Specifically, we demonstrated how to balance tradeoffs between yield and carbon credit income that arise from tillage and winter cover crop actions (cereal rye, Secale cereale L. and crimson clover, Trifolium incarnatum L.) in a soybean (Glycine max L.) production system in Mississippi. Results indicated that a producer could minimize losses to net yield income by adopting no-till if already using cover crops. There was also evidence that carbon credit income could offset losses to yield income when adopting CS in place of traditional actions. Identifying risks to yield income and SOC storage can help design carbon neutrality policies that have minimum impact on a producer’s income. History: This paper has been accepted for the Decision Analysis Special Issue on Decision Analysis to Advance Environmental Sustainability. Funding: This work was supported by the USDA-ARS [Grants 58-0200-0-002 (Advancing Agricultural Research) and 58-6001-8-003] and the USDA National Institute of Food and Agriculture [McIntire Stennis Project 1020959]. Supplemental Material: The online appendix is available at https://doi.org/10.1287/deca.2023.0478 .

Evaluation of winter cover crop methods for management of flatheaded appletree borer (Coleoptera: Buprestidae).

Winter cover crops grown at the base of red maples (Acer rubrum L.) can reduce flatheaded appletree borer (Chrysobothris femorata Olivier; Coleoptera: Buprestidae; FAB) damage by both physically blocking preferred oviposition sites and altering the environment around them. However, cover crop competition negatively affects tree growth. To investigate long-term cover crop effects, trees grown with cover crop for 2 yr were transitioned to a standard herbicide practice. After 4 yr, trees in the initial 2 yr cover crop plots were 1 yr behind in growth compared to trees grown in bare rows for all 4 yr. Most growth reduction occurred in the first year following transplant. Additional borer losses of 1-2% per year were observed in production years 3 and 4. A second experiment answered 2 questions: Can killing the cover crop once it reaches maximal height protect trees from borers while also reducing competition and thereby increase tree growth? and Do herbicide applications increase borer attacks? In this experiment, red maples were grown with (i) a standard herbicide program, (ii) a mulch mat, (iii) a cover crop that was killed early, or (iv) a cover crop allowed to senesce naturally. Evaluations after 2 yr indicated early kill of the cover crop was not enough to improve tree growth. Further, trees in the early kill cover crop treatment had the most FAB attacks. Cover crops allowed to senesce naturally reduced FAB attacks in both studies; however, more work is needed to minimize disparities in tree growth during the initial year post-transplant and determine the causal relationship between herbicide use and borer attacks.

Effects of winter cover crops from different functional groups on soil-plant nitrogen dynamics and silage maize yield

Cover crops (CCs) are known for their multiple benefits in agro-ecosystems. This is especially true in intensive cropping systems with high nitrogen (N) inputs and considerable post-harvest residual N. Furthermore, research has shown that CCs have the potential to reduce nitrate N leaching losses. The efficacy of ecosystem services by implementing CCs is related to site-specific management optimisation as well as species individual traits. In this study, four winter CCs from different functional groups (oil radish, saia oat, spring vetch, winter rye) were compared to a bare fallow which served as control. Furthermore, the CCs were evaluated in terms of the effects on N immobilisation, mineralisation dynamics, N uptake and biomass accumulation of silage maize used as a subsequent cash crop. Field trials were conducted at two locations, during two consecutive establishment years, with silage maize fertilised with two different N levels (no/sufficient fertiliser). Successful CC growth accumulated between 0.89 (volunteer oilseed rape (OSR)/vetch mixture) and 3.50 Mg dry matter ha−1 (rye). The CCs accumulated between 39 (rye) and 79 kg N ha−1 (radish) in aboveground biomass and significantly reduced soil mineral nitrogen (SMN) by 12 kg N ha−1 during the winter growth period. In the subsequent maize growing season all CCs increased SMN by 45 kg N ha−1 on average compared to the fallow. The C/N ratios in the aboveground biomass of CCs varied between 10.5 and 27.0 in the order: OSR/vetch < radish < rye < oat. Nitrogen uptake of the subsequent silage maize was significantly increased by 53 and 54 kg N ha−1 compared to the fallow without and with added N, respectively. Net N mineralisation indicated periods with net SMN immobilisation under sufficient N fertilisation and was more pronounced after CCs than fallow. Effective N mineralisation during maize growth was significantly higher following CCs without N fertilisation (51 kg N ha−1); however, the increase was lower with added N (43 kg N ha−1). Cover crops increased apparent fertiliser N immobilisation rates during the maize cropping period by 28 % (maize following bare fallow) to 34 % (OSR/vetch > radish, no effect for rye). Maize dry matter yield (15.58/17.33 Mg ha−1 without/with N) did not significantly differ between CCs and bare fallow treatments. Overall, there was a trade-off between N buffering during winter (CC biomass as main driver for N uptake), N supply and utilisation of the subsequent cash crop (C/N ratio of CC residues as main driver for mineralisation) where radish indicated the greatest net benefits for silage maize cropping systems without yield effects.

Winter Cover Crops Improve Soil Health in Texas Cotton

CSA NewsEarly View SOCIETY SCIENCE Winter Cover Crops Improve Soil Health in Texas Cotton First published: 15 May 2023 https://doi.org/10.1002/csan.21029Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Early ViewOnline Version of Record before inclusion in an issue RelatedInformation

Increasing potato profitability through rotation systems and winter cover, nitrogen fertilizer, and supplemental irrigation in Atlantic Canada

AbstractAverage potato yield in Prince Edward Island, Canada, has been stagnant since 2006. Two field studies were conducted on Charlottetown fine sandy loam soil to address this concern. In the first experiment, two alternative crop rotations, grain corn (Zea mays L.)–sorghum sudan grass (Sorghum × drummondii)–potato (C–SS–P) and soybean (Glycine max (L.) Merr.)–mustard (Brassica juncea (L.) Czern.)–potato (Soy–M–P), were compared to a conventional barley (Hordeum jubatum L.) (under seeded with red clover)–red clover (Trifolium pratense L.)–potato (Solanum tuberosum L.) (B–RedCl–P) rotation. This experiment was conducted for two 3‐year cycles comparing the effects of potato rotation, nitrogen fertilizer, and supplemental irrigation. The second experiment evaluated the inclusion of winter cover crops in a 3‐year potato crop rotation. The profitability of potatoes in each rotation was assessed using a stochastic budget of yields and fertilizer and crop prices. The effects of supplemental irrigation were not significant; however, nitrogen fertilization increased potato yields by 48%. Potato yields and net revenues in C–SS–P increased by 10.5% and 32.6% and in Soy–M–P by 6.7% and 20.5%, respectively, compared to potato in B–RedCl–P rotation. The use of winter rape cover increased potato yields by 18.6% compared to a system without winter covers, although some of these increases could be due to the use of sudan grass instead of red clover in B–RedCl–P rotation. It is recommended that potato producers implement the alternative rotation with additional fertilization and winter cover crops to increase yields and profits.

Cover crop forage potential and subsequent sorghum silage yield and nutritive value

AbstractAchieving high forage production—quantity and quality—could be challenging, specifically in water‐limited areas. Intensifying cropping systems with cover crops can provide agronomic and ecosystem service benefits. However, the impacts of cover crops on forage production have not been well studied. This study evaluated the effects of cover crops (grasses + brassicas + legumes [GBL], grasses + brassicas [GB], grasses + legumes [GL], and no cover crop [NCC] control) on sorghum silage [Sorghum bicolor (L.) Moench] yield and nutritive value over 3 years in a semiarid irrigated condition. Cover crops produced 2.1–6.0 Mg ha−1 of annual average harvestable biomass with similar forage nutritive value among treatments. In 2018–2019, sorghum silage yield was 38%–43% greater with all cover crops than with NCC. However, in 2019–2020, only GB had a 23% greater sorghum silage yield than NCC. The neutral detergent fiber content in sorghum silage was 4.8%–5.1% greater with all cover crops, and crude protein was 3%–8% lower with GL and GBL compared to NCC. Therefore, total digestible nutrients, relative forage quality, and milk production potential of sorghum silage were 5%–8%, 11%–19%, and 8%–16% greater, respectively, with NCC than with cover crops. This study demonstrates that replacing fallow with winter cover crops in irrigated silage production systems could provide good quality forage from cover crops without a decrease in subsequent sorghum silage yield. Sorghum silage quality slightly decreased with cover cropping. Nevertheless, cover crop integrated systems could be an alternative for farmers facing declining water availability for irrigated crop production.

Ecological restoration of sloping land using straw checkerboard barriers seeded with winter cover crops

In order to know, if Straw checkerboard barriers (SCB) technology could support the soil capabilities to grow plants and recovery ecological services via alleviate drought stress or amendment of soil attributes, an experiment was carried out in 2018. Checkerboards were setup in a 1 × 1 m pattern with rice residues. Seeds of sainfoin (Onobrychis sativa), rye (Secale montanum) and tall wheatgrass (Agropyron sp) were sown at different microenvironments of checkerboards include in borders and centers of the straw barrier and bare soil as the control. Growth analysis showed that rye plants in the border of the barriers showed on average 22, 100 and 60% higher plant height, shoot fresh weight, and shoot dry weigh than the bare soil respectively. Higher amounts of chlorophylls and carotenoids were also recorded for rye plants and the border of the SCB led to significant increase in these pigments. Rye plants maintained the highest RWC and lowest electrolyte leakage value among the crops. Higher RWC (18%) and lower electrolyte leakage (13%) was recorded in the border of the barriers as compare to the bare soil. Sainfoin and rye recorded higher malondialdehyde content while plants grown in the borders recorded lower amounts of malondialdehyde against plants in the bare soil. Soil water storage dynamics showed that during the growing season the barriers retained higher soil moisture. In the case of NPK, higher soil total nitrogen, available phosphorus and potassium, and soil organic matter content were observed in SCB. Principal component analysis (PCA) of morphophysiological characteristics of cover crops indicated that rye had higher shoot fresh weight, shoot dry weight, chlorophyll a and carotenoids compare to sainfoin. For soil characteristics the PC1 represents the changes between the border of barriers, center of barriers and bare soil. Redundancy Analysis (RDA) showed that in first axe available phosphorus and soil organic matter are the most important variables that cause the greatest impact on the changes related to the morphophysiological characteristics of rye plants. Finally SCB could be deemed as an effective management strategy in semi-arid areas, as an important method for conserving natural resources and sustaining productivity and rye had better ability to survive and benefit in such dry conditions.

Long-term reduced tillage and winter cover crops can improve soil quality without depleting moisture

California farmers who use reduced-disturbance tillage and winter cover cropping can boost production and improve soil health. However, some farmers are hesitant to try these conservation practices due to uncertainty about whether planting winter cover crops will deplete soil moisture in already drought-stricken regions. Our study addresses these concerns by looking at how long-term reduced-disturbance tillage and winter cover cropping, compared to fallowed soils with standard tillage, affected soil moisture. Although we found a statistical difference in total soil water content, the difference was only about 0.3 inches of water per foot of soil. On average, the soil water content of the top 0–96 inches was highest for the reduced-disturbance fields with winter cover crops. This was especially evident during our driest field season, from November 1, 2017, to March 15, 2018, when cumulative rainfall was only 1.9 inches. Our findings show that winter cover cropping and reduced-disturbance tillage can improve soil without depleting soil water levels in row crops.

Integrating weed-suppressive cultivar and cover crops for weed management in organic sweetpotato production

AbstractField studies were conducted in 2021 in Kibler and Augusta, AR, to determine the effect of winter cover crops and cultivar selection on weed suppression and sweetpotato [Ipomoea batatas (L.) Lam.] yield. The split-split-plot studies evaluated three cover crops [cereal rye (Secale cereale L.) + crimson clover (Trifolium incarnatum L.)], [winter wheat (Triticum aestivum L.) + crimson clover], and fallow; weeding (with or without); and four sweetpotato cultivars (‘Heartogold’, ‘Bayou-Belle-6’, ‘Beauregard-14’, and ‘Orleans’). Heartogold had the tallest canopy, while Beauregard-14 and Bayou Belle-6 had the longest vines at 5 and 8 wk after sweetpotato transplanting. Sweetpotato canopy was about 20% taller in weedy plots compared with the hand-weeded treatment, and vines were shorter under weed interference. Canopy height and vine length of sweetpotato cultivars were not related to weed biomass suppression. However, vine length was positively correlated to all yield grades (r &gt; 0.5). Weed biomass decreased 1-fold in plots with cover crops compared with bare soil at Augusta. Cover crop biomass was positively correlated with jumbo (r = 0.29), no. 1 (r = 0.33), and total sweetpotato yield (r = 0.34). Jumbo yield was affected the most by weed pressure. On average, sweetpotato total yield was reduced by 80% and 60% with weed interference in Augusta and Kibler, respectively. Bayou Belle-6 was the high-yielding cultivar without weed interference in both locations. Bayou Belle-6 and Heartogold were less affected by weed interference than Beauregard-14 and Orleans.

Sustainability of cover cropping practice with changing climate in Illinois

Climate change could adversely impact the best management practices (BMPs) designed to build a sustainable agro-ecological environment. Cover cropping is a conservation practice capable of reducing nitrate-nitrogen (NO3–N) loadings by consuming water and nitrate from the soil. The objective of this study was to investigate how climate change would impact the proven water quality benefits of cereal rye as a winter cover crop (CC) over the climate divisions of Illinois using the DSSAT model. Moreover, this study explores the sustainability of the CC with the changing climate conditions by using five regional climate models (RCMs) projections of two warming scenarios-rcp45 (a medium emission scenario - radiative forcing of 4.5 W/m2) and rcp85 (a high emission scenario - radiative forcing of 8.5 W/m2)). The CC impact simulated in the warming scenarios for the near-term (2021–2040) and the far-term future (2041–2060) were compared with the baseline scenario (2001–2020). Our results conclude that the climate change may negatively impact [average of CC and no CC (NCC)] maize yield (−6.6%) while positively affecting soybean yield (17.6%) and CC biomass (73.0%) by the mid-century. Increased mineralization caused by rising temperature could increase the nitrate loss via tile flow (NLoss) and nitrate leached (NLeached) up to 26.3% and 7.6% on average by the mid-century in Illinois. Increasing CC biomass could reduce the NLoss more considerably in all the scenarios compared to the baselines. Nevertheless, the NLoss level in the CC treatment can increase from the near-term to far-term future and could get closer to the baseline levels in the NCC treatment. These results suggest that CC alone may not address nitrate loss goals via subsurface drainage (caused by increasing N mineralization) in future. Therefore, more robust and cost-effective BMPs are needed to aid the CC benefits in preventing nutrient loss from the agricultural fields.

Influence of cover crops on soybean yield and partial returns as an alternative to double‐crop soybean in Arkansas

AbstractThe number of hectares dedicated to winter wheat (Triticum aestivum L.) in the southern United States has been trending downward for almost a decade, presenting an opportunity for producers to utilize alternatives in their soybean [Glycine max (L.) Merr.] rotations, such as winter cover crops. A study was established to compare the cover crops to traditional cropping systems by determining the effect each had on a successive soybean crop and to examine partial economic returns. Cropping systems implemented were winter fallow, winter wheat, and seven cover crop treatments, including cereal rye (Secale cereale L.), black‐seeded oat (Avena sativa L.), barley (Hordeum vulgare L.), Austrian winter pea (Pisum sativum L.), blue lupin (Lupinus angustifolius L.), Blend 1 (cereal rye, crimson clover [Trifolium incarnatum L.], seven‐top turnip [Brassica rapa L.]). and Blend 2 (black‐seeded oats and Austrian winter pea). The winter cropping system did not affect the soybean plant population (p = 0.32). Soybean grain yield varied among the different winter cropping systems (p &lt; 0.01) with yields ranging from 3346 to 3906 kg ha−1. The soybean double‐crop system ($1383.02 ha−1) and soybean following winter cover crops ($1239–1380 ha−1) produced similar partial returns but both were greater than soybean following winter fallow ($1217.81 ha−1) (p &lt; 0.01). Soybean yields and partial returns were the highest when following Blend 2. Results of this study showed that winter cover crops can provide an adequate alternative to both winter fallow and traditional winter wheat soybean double‐crop systems in the mid‐southern United States.

Mitigation of greenhouse gases emission affected by no-tillage and winter cover crops in a subtropical paddy rice ecosystem

Paddy rice production based on traditional soil management emits large amounts of methane (CH 4 ) into the atmosphere. This study assessed the potential of no-tillage (NT) and winter cover crops (WCC) to mitigate net greenhouse gas (GHG) emissions in a subtropical paddy rice ecosystem. A long-term (20-yrs) experiment was evaluated regarding the effect of NT combined with winter fallow or three WCC (ryegrass, white oat, and birdsfoot trefoil) on seasonal CH 4 -C and nitrous oxide (N 2 [...]

Winter cover crops to reduce herbicide inputs into spring-planted maize pastoral systems in New Zealand

ABSTRACT 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.