Winter Rye Cover Crop Research Articles

N supply and yield of sugar beet after cover cropping: effects of cover crop species and management

Despite long-time practice, the effect of cover crop (CC) cultivation on N supply and yield of subsequent sugar beet (SB) is not clear for the temperate climate of Central Europe. To elucidate, four field trials with oil radish, spring vetch, saia oat, and winter rye CCs were conducted on typical loessial soil in Germany. Mineral fertilizer N dose was varied as second factor: zero (N0) and optimum dose (Nopt). Biomass characteristics before winter, soil mineral nitrogen content in spring (SMN), and sugar yield and total plant N content of SB were measured. The CC N effect (Neff), calculated as the difference in SB N uptake after CC minus bare fallow, was computed for the periods sowing-summer (July/August) and summer-harvest. On average, sugar yield was decreased after rye and increased after vetch CC compared to bare fallow which was more pronounced under N0 than Nopt. In the period sowing-summer, characterized by a high SB N demand, Neff was close to 0 kg N ha–1 after rye and up to +30 kg N ha–1 after vetch. In contrast, Neff in summer-harvest was negative, amounting up to –80 kg N ha–1 after radish and rye. Regression analysis revealed a significant relationship between Neff in the period sowing-summer and the sugar yield difference between the cover crop treatments and bare fallow (R2 = 0.29). A multiple regression analysis (R2 = 0.68) indicated that high CC biomass combined with a large negative spring SMN difference between CC treatment and fallow caused a large yield penalty, which can be compensated for by elevated N fertilization. Moreover, CC management ensuring either a limited CC biomass or low SMN difference of CCs compared to fallow by e.g., later sowing, less vital CC species or early CC termination, will likely secure higher SB yield after CCs than fallow.

Cover crops and deep‐soil C accumulation: What does research show after 10 years?

AbstractThe extent to which cover crops (CCs) accumulate soil organic carbon (SOC) in the entire soil profile is still unclear. We measured SOC, permanganate oxidizable C (POX‐C), and particulate organic matter (POM) concentrations down to 60‐cm soil depth in early [2–3 week before corn (Zea mays L.) planting]‐ and late‐terminated (at corn planting) winter rye (Secale cereale L.) CCs in rainfed and irrigated no‐till continuous corn systems in the U.S. Corn Belt after 10 years. CCs increased SOC stock and SOC, POX‐C, and POM concentrations but only in the irrigated system in the upper 5‐cm depth. Late‐terminated CC increased SOC concentration by 4.710 ± 3.501 g kg−1 and accumulated SOC at 0.207 ± 0.145 Mg C ha−1 year−1. It increased POX‐C and POM concentrations, on average, by 1.194 times. CCs likely increased SOC in the irrigated system by producing more biomass (2.247 ± 0.370 Mg ha−1) than in the rainfed system (0.949 ± 0.338 Mg ha−1). At least 2 Mg ha−1 of CC biomass may be needed to increase SOC. Because winter CCs often produce <1 Mg ha−1 of biomass when typically planted late and terminated early, extending the CC growing window by terminating CCs at or after crop planting (planting green) may boost CC biomass and SOC accumulation, although high‐C soils or Mollisols, such as our study soils (>22 g C kg−1), may limit SOC gains. We submit CCs would sequester more SOC in low‐C, eroded, and low‐fertility soils. Overall, winter rye CCs minimally alter soil C in the soil profile in no‐till continuous corn systems after 10 years.

Winter Rye Cover Crops Shelter Competent Squash Phyllosphere Bacteria to Reduce Pseudomonas syringae pv. lachrymans Growth and Angular Leaf Spot Symptoms.

Cover crops, a soil conservation practice, can contribute to reducing disease pressure caused by Pseudomonas syringae, considered one of the most important bacterial plant pathogens. We recently demonstrated that the phyllosphere (leaf surface) bacterial community structure changed when squash (Cucurbita pepo) was grown with a rye (Secale cereale) cover crop treatment, followed by a decrease of angular leaf spot disease symptoms on squash caused by P. syringae pv.lachrymans. Application of biocontrol agents is a known agricultural practice to mitigate crop losses due to microbial disease. In this study, we tested the hypothesis that some phyllosphere bacteria promoted when squash is grown on cover crops could be isolated and used as a biocontrol agent to decrease angular leaf spot symptoms. We grew squash during a 2-year field experiment using four agricultural practices: bare soil, cover crops, chemically terminated cover crops, and plastic cover. We sampled squash leaves at three different dates each year and constructed a collection of cultivable bacterial strains isolated from squash leaves and rye cover crop material. Each isolated strain was identified by 16S rRNA gene sequencing and used in in vitro (Petri dish) pathogen growth and in vivo (greenhouse) symptom control assays. Four bacterial isolates belonging to the genera Pseudarthrobacter, Pseudomonas, Delftia, and Rhizobium were shown to inhibit P. syringae pv. lachrymans growth and angular leaf spot symptom development. Strikingly, the symptom control efficacy of all strains was stronger on older leaves. This study sheds light on the importance of bacterial isolation from cover crop sources to promote disease control. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Early‐season biomass and weather enable robust cereal rye cover crop biomass predictions

AbstractFarmers need accurate estimates of winter cover crop biomass to make informed decisions on termination timing or to estimate potential release of nitrogen from cover crop residues to subsequent cash crops. Utilizing data from an extensive experiment across 11 states from 2016 to 2020, this study explores the most reliable predictors for determining cereal rye cover crop biomass at the time of termination. Our findings demonstrate a strong relationship between early‐season and late‐season cover crop biomass. Employing a random forest model, we predicted late‐season cereal rye biomass with a margin of error of approximately 1,000 kg ha−1 based on early‐season biomass, growing degree days, cereal rye planting and termination dates, photosynthetically active radiation, precipitation, and site coordinates as predictors. Our results suggest that similar modeling approaches could be combined with remotely sensed early‐season biomass estimations to improve the accuracy of predicting winter cover crop biomass at termination for decision support tools.Core Ideas Cereal rye winter cover crop biomass modeled on data from 35 site‐years. We found a strong relationship between early and late‐season biomass. Random forest model with early‐season biomass and weather data performed well. Similar approach could improve decision support tools for cover crop management.

U.S. cereal rye winter cover crop growth database

Winter cover crop performance metrics (i.e., vegetative biomass quantity and quality) affect ecosystem services provisions, but they vary widely due to differences in agronomic practices, soil properties, and climate. Cereal rye (Secale cereale) is the most common winter cover crop in the United States due to its winter hardiness, low seed cost, and high biomass production. We compiled data on cereal rye winter cover crop performance metrics, agronomic practices, and soil properties across the eastern half of the United States. The dataset includes a total of 5,695 cereal rye biomass observations across 208 site-years between 2001–2022 and encompasses a wide range of agronomic, soils, and climate conditions. Cereal rye biomass values had a mean of 3,428 kg ha−1, a median of 2,458 kg ha−1, and a standard deviation of 3,163 kg ha−1. The data can be used for empirical analyses, to calibrate, validate, and evaluate process-based models, and to develop decision support tools for management and policy decisions.

Effects of Different Cover Crops and Amendments on Soil and Crop Properties in Organic Vegetable Production

The impacts of two different cover crop (CC) strategies, as well as compost, silicon (Si), and biocontrol (BC) soil amendments were evaluated on soil chemical and biological properties, crop development and yield, and disease and pest issues in organic vegetable production, as represented by legume (green snap bean), cucurbit (green zucchini squash), and solanaceous (sweet pepper) vegetable crops, in a three-year field trial in Maine, USA. A multi-species CC mixture (6 crops, including legumes, grasses, and brassicas) was compared with a standard winter rye CC for potential benefits on soil properties and biomass production. Soil amendments included a commercial organic fertilizer alone, composted dairy manure, compost plus BC (commercial formulations of Trichoderma and Streptomyces spp.), and compost plus Wollastonite, a natural source of Si. Poor stand establishment of some components of the multi-species CC mixture resulted in lower biomass and ground cover relative to winter rye, but had no effect on crop development or yield. Compost amendments increased soil pH, organic matter, and nutrient contents, as well as yields of bean, zucchini, and peppers relative to a fertilizer-only treatment. Additions of Si increased Si content in plant leaves and reduced powdery mildew on squash and leaf necrosis of beans. In the absence of substantial soilborne disease, BC provided only marginal reductions in powdery mildew and leaf necrosis and no effects on yield. These results help define specific management practices to improve organic vegetable production and provide useful information and options for growers.

Did cover crop or animal manure ameliorate corn residue removal effects on soil mechanical properties after 10 years?

Crop residue removal may negatively affect soil mechanical properties, which are key components of soil quality. To evaluate potential long-term effects, we assessed the 10-yr impact of corn (Zea mays L.) residue removal (59 % of non-grain biomass annually) on surface soil mechanical properties (0–20 cm). We also evaluated whether adding carbon (C) amendments, such as using a winter rye (Secale cereale L.) cover crop or surface-applying cattle manure (24 Mg ha−1 biannually) can ameliorate the effects of crop residue removal. This long-term study was under irrigated no-till continuous corn on a silt loam soil in south-central Nebraska, USA. Measurements included soil penetration resistance, field bulk density, aggregate strength, Atterberg limits (liquid limit, plastic limit, and plasticity index), Proctor maximum bulk density, and the water content at which the Proctor maximum bulk density (critical water content) occurs. Reduction in soil organic carbon (SOC) concentration explained most of the changes in soil mechanical properties. Long-term corn residue removal increased penetration resistance (+40 %) for the 0–20 cm depth, and reduced aggregate strength (−44 %), plasticity index (−22 %), and critical water content (−13 %) in the 0–5 cm depth. Residue removal also reduced field bulk density (−5%), liquid limit (−12 %), and plastic limit (−10 %) in the 0–10 cm depth, but increased Proctor maximum bulk density (+8 %) in the 0–5 cm depth. Winter rye cover crop reduced field bulk density (−5%, 0–15 cm depth) and increased penetration resistance (+52 %, 0–20 cm depth). Surface-applied manure amendments increased the near-surface soil liquid limit (+8 %) and plastic limit (+8 %) in the 0–5 cm depth. Given the high rate of residue removal used in this experiment, our findings support that excessive corn residue removal over the long-term (∼10 years) negatively affects near-surface soil mechanical properties, but that use of winter rye cover crop or surface-applied manure can minimally to partially ameliorate these effects.

Cover crops and soil health in rainfed and irrigated corn: What did we learn after 8 years?

AbstractDuration of cover crop (CC) management, CC biomass production, and other factors could impact how CC affects soil health. We studied the 8‐year cumulative impacts of winter rye (Secale cereale L.) CC on soil physical, chemical, and biological properties in rainfed and irrigated no‐till corn (Zea mays L.)‐based systems in the western US Corn Belt. Average annual CC biomass production was 0.56 ± 0.51 Mg ha−1 at the rainfed site and 0.98 ± 0.95 Mg ha−1 at the irrigated site. After 8 years, CC improved particulate organic matter (POM) and mean weight diameter of water‐stable aggregates (MWD) compared with no CC in the 0–5 cm soil depth at both sites. Cover crop increased total POM concentration by 2.8 mg g−1 at the rainfed site and by 13.4 mg g−1 at the irrigated site, while it increased MWD by 0.39 mm at the rainfed site and by 0.79 mm at the irrigated site. Also, CC increased soil C at a rate of 0.125 Mg ha−1 year−1 in the 0–5 cm depth but only at the rainfed site. Cover crop affected neither water infiltration nor available water but improved microbial biomass. Changes in other properties were site‐dependent. Cover crop improved many soil properties after 8 years even though measurement taken after 4 years showed no significant effect of CC, which indicates CC slowly impacts properties in this environment. Low CC biomass production and high biomass input from corn‐based systems may explain the slow soil response. In general, winter rye CC enhances near‐surface soil properties in the long term.

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.

Poorly drained depressions can be hotspots of nutrient leaching from agricultural soils.

Much of the US Corn Belt has been drained with subsurface tile to improve crop production, yet poorly drained depressions often still flood intermittently, suppressing crop growth. Impacts of depressions on field-scale nutrient leaching are unclear. Poor drainage might promote denitrification and physicochemical retention of phosphorus (P), but ample availability of water and nutrients might exacerbate nutrient leaching from cropped depressions. We monitored nitrate, ammonium, and reactive P leaching across multiple depression-to-upland transects in north-central Iowa, using resin lysimeters buried and retrieved on an annual basis. Crops included conventional corn/soybean (Zea mays/Glycine max) rotations measured at fields with and without a winter rye (Secale cereale) cover crop, as well as juvenile miscanthus (Miscanthus × giganteus), a perennial grass. Leaching of nitrogen (N) and P was greater in depressions than in uplands for most transects and years. The median difference in nutrient leaching between paired depressions and uplands was 56kg N ha-1 year-1 for nitrate (p=0.0008), 0.6kg N ha-1 year-1 for ammonium (p=0.03), and 2.4kg P ha-1 year-1 for reactive P (p=0.006). Transects managed with a cover crop or miscanthus tended to have a smaller median difference in nitrate (but not ammonium or P) leaching between depressions and uplands. Cropped depressions may be disproportionate sources of N and P to downstream waters despite their generally poor drainage characteristics, and targeted management with cover crops or perennials might partially mitigate these impacts for N, but not necessarily for P.

Simulated impacts of winter rye cover crop on continuous corn yield and soil parameters

AbstractCover crops (CC) provide numerous ecosystem services such as improving soil health, reducing nutrient loss, increasing productivity, and mitigating greenhouse gas emission. However, adoption of CC has been hindered by perceived negative impacts on main crop productivity and additional production costs. This is partly attributed to the gap in current state of knowledge in CC and its interaction with main crop production under different biophysical conditions. In this study, Decision Support System for Agrotechnology Transfer model was used to evaluate the long‐term impact of cereal rye (Secale cereale L.) on corn (Zea mays L.) yield, soil organic carbon (SOC), nitrate leaching, soil water, and drainage for a range of climate, soil, and irrigation management in Eastern and Central Nebraska. A 30‐year (1991–2020) simulation showed no difference in corn yield and SOC between CC and no‐cover crop treatments at both sites under irrigated and rainfed conditions. However, CC resulted in reduction of N loss by up to 48% at the Eastern Nebraska Research and Extension Center and 24% at South Central Agricultural Laboratory under irrigation. Cereal rye has no significant effect on total soil water but, a significant reduction in cumulative subsurface drainage of 44% was determined at both sites. This study has shown the possible effect of cover crop on corn crop yield and soil properties over different regions in Nebraska. Future research extending the scope and geographic area is needed to test and quantify possible impacts of multiple CC species under diverse management and biophysical conditions.

Long term influence of alternative corn cropping practices and corn-hay rotations on soil health, yields and forage quality

Modifications to continuous corn production systems can reduce environmental impacts and soil degradation, yet the social viability of these modifications is linked to the degree to which they also influence yields and crop quality. In this study, we focus on forage production systems and evaluate how yields, crop quality, soil health indicators, and associated ecosystem services are influenced by corn-hay rotation treatments, cover cropping, and tillage reduction in silage production using a unique 10-year dataset from Borderview Research Farm in Vermont, United States. Physical, chemical, and biological soil health indicators were monitored annually alongside yields and crop quality in a randomized complete block design experiment. We use a mixed model analysis of variance approach to demonstrate significant influences of time and treatments on yields, crop quality and soil health parameters (at p &amp;lt; 0.05). The winter rye cover crop treatment had no significant influence in this study. No-till significantly increased aggregate stability and had no significant effect on other metrics. When cover crop and no-till were combined, they significantly increased soil organic matter content, respiration and aggregate stability. The cover crop, no-till, and no-till cover crop combination treatments had no significant effect on yields or forage quality, suggesting these conservation practices can be adopted without sacrificing yields. Our study also found that corn-hay rotations can significantly increase soil organic matter, respiration, aggregate stability, and crude protein content compared to continuous corn, but they can negatively influence active carbon, total dry matter yield and digestibility. The length of rotation influences the degree to which corn-hay rotations maintain or reduce yields when compared to continuous corn. Shorter rotations of perennial forages (4 years of hay, 6 years of corn) can sustain dry matter yields that are not significantly different from continuous corn, but longer perennial forage rotations (8 years of hay, 2 years of corn) will significantly reduce overall dry matter yields. Among the treatments, no-till in combination with cover cropping in corn silage fields, and a rotation of 4 years of hay to 6 years of corn are likely to achieve the greatest overall benefits in forage production systems.

Winter rye cover crop biomass, nutrient uptake, and quality in response to fall and spring N fertilization

Growers in Illinois often apply manure or add starter fertilizers that contain nitrogen (n) in the fall to save time for other farming operations in the spring. Fall manured fields sometimes receive a starter n in spring as part of the operation. We hypothesized that winter rye (Secale cereale) (wr) cover crop could capture the applied n which in turn changes wr dry matter (dm) biomass, nutrient uptake, and c accumulation capacity, and wr quality (ash, lignin, and c concentrations along with c:n, and lignin:n ratios). Two separate trials with randomized complete block design at two separate locations in Southern Illinois were conducted in 2020 and 2021. Trial one had two rates of fall-applied n (0 vs. 56 kg n ha−1), and trial two had initial fall manure to all plots plus four rates of n fertilizer in spring (0, 23, 47, and 71 kg ha−1). Results for trial one indicated that fall n fertilization had no effect on wr biomass, nutrient uptake, and quality parameters due to loss of applied n in the fall. Spring n application did not affect wr dm biomass but linearly increased n, phosphorus (p), and potassium (k) concentrations, their uptake, c concentration, and decreased c:n and lignin:n ratios. We concluded that spring n fertilization could facilitate n decomposition of wr by decreasing its c:n and lignin:n ratio and help increasing the wr nutrient uptake capacity, but fall n application should be avoided to prevent n loss to the environment and decrease the cost of operation.

Rye-soybean double-crop: planting method and N fertilization effects in the North Central US

AbstractDouble-cropping winter rye cover crops (CC) with soybean in the North Central US could help with the global effort to sustainably intensify agriculture. Studies addressing the management of these systems are limited. Therefore, a field study was conducted from 2017 to 2019 in Central Iowa, US to evaluate winter rye CC biomass production, aboveground N accumulation, estimated economics, estimated within-field energy balance and estimated greenhouse gas (GHG) emissions under three N application rates (0, 60, 120 kg N ha−1) and three planting methods (pre- and post-harvest broadcast and post-harvest drilling). Averaged over N rates, all planting methods resulted in &gt;5.0 Mg ha−1 year−1 rye aboveground biomass dry matter. Averaged over the 2-year study and compared with unfertilized treatments, applying 60 kg N ha−1 produced 1.1 Mg ha−1 more aboveground biomass (6.1 vs 5.0 Mg ha−1), accumulated 30 kg ha−1 more N in aboveground biomass (88 vs 58 kg N ha−1), and led to 20 GJ ha−1 more net energy. Biomass production was not significantly higher with 120 kg N ha−1 compared with the 60 kg N ha−1 rate. Even when accounting for an estimated 0.75 Mg ha−1 of above ground rye biomass left in the field after harvesting, more N was removed than applied at the 60 kg N ha−1 rate. The minimum rye prices over the 2-year study needed for double-cropping winter rye CC to be profitable (breakeven prices) averaged $117 and $104 Mg−1 for the 0 and 60 kg N ha−1 rates, which factors in estimated soybean yield reductions in 2019 compared with local averages but not off-site transportation. GHG emissions were estimated to increase approximately threefold between the unfertilized and 60 kg N ha−1 rates without considering bioenergy offsets. While environmental tradeoffs need further study, results suggest harvesting fertilized rye CC biomass before planting soybean is a promising practice for the North Central US to maximize total crop and net energy production.

Field Studies on the Effect of Rye Cover Crop on Soybean Root Disease and Productivity

Cover crops improve soil and water quality in annual cropping systems, but knowledge of their impact on soybean ( Glycine max L.) seedling and root diseases is limited. The effects of winter rye cover crops ( Secale cereale L.) on soybean population, biomass, root morphology, seedling and root diseases, pathogen incidence, canopy reflectance, and yield were assessed over 2 years in Iowa and Missouri, U.S.A. Plots without a rye cover crop were compared with plots with early-kill rye and late-kill rye cover crops, which were terminated 34 to 49 days or 5 to 17 days before soybean planting, respectively. Soybean shoot dry weight, root rot severity, and incidence of Fusarium spp. and Pythium spp. on roots were not influenced by the treatments. Soybean grain yield and plant population were reduced in the presence of rye in 2 site years, increased in 1 site year, and unchanged in the remaining site years. Soybean canopy reflectance was measured at 810 nm, and measurements were first made at 70 to 80 days after planting (DAP). At least five measurements were obtained at 7- to 15-day intervals, ending at 120 to 125 DAP. Measurements at approximately 120 to 125 DAP differed by treatments but were not consistently associated with the presence or absence of a rye cover crop. Our field studies suggest that Iowa and Missouri soybean farmers can use winter rye as a cover crop in soybean fields with low seedling disease pressure without increasing the risk of seedling and root diseases or suppressing yield. [Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Cereal rye (Secale cereale L.) cover crop improves soil physico-chemical properties with no influence on soybean (Glycine max L.) root growth parameters

Planting winter cover crops (CC) in soybean cropping systems is expected to offer various environmental benefits including soil health and fertility besides enhanced cash crop productivity. In a three-year study (2018–2021) conducted on a Dundee silt loam, we assessed the impact of introducing rye (Secale cereale L.) CC during the winter fallow period on soil organic carbon (SOC), soil organic matter (SOM), soil total nitrogen (STN), bulk density (BD), saturated hydraulic conductivity (Kfs), soil penetration resistance (SPR), and water-stable aggregates (WSA). Three treatments evaluated were: i) no cover crop (NC), ii) winter rye as CC rolled when green and desiccated after soybean planting (GR), and iii) winter rye CC desiccated and rolled before planting soybean (BR) in a randomized complete block design with six replications. The depth of the soil sampling in 2019 was 0-15 and 15-30 cm while 0-10, 10-20 and 20-30 cm depth soil sampling was done in 2020 and 2021. Effects of BR and GR on soybean root growth characteristics (number of roots, root length and root angle) were measured using a CID 600 root scanner. The results showed that CC (both BR and GR) improved SOC by 7 to 12.5%, soil organic matter by 9 to 15%, STN by 13 to 29%, WSA by 26 to 68%, Kfs by 5 to 9% and reduced BD by 8% and SPR by 14 to 18% compared to NC (P&amp;lt;0.05). However, there were no differences between BR and GR treatments. Root characteristics of soybean in the NC, BR and GR treatments were similar. Rye CC fits into the existing soybean production system in the Lower Mississippi Delta with a potential to augment soil-physico chemical properties, thus offering agro-ecosystem services which may not necessarily lead to an impact on soybean root growth traits.

Effect of Rye cover crop on weed control, soybean (Glycine max L.) yield and profitability

Considerable variations in farm productivity were reported across soils and climates when winter cover crops (CC) were rotated with summer main cash crops. Hence, a three-year field study (2019-2021) was conducted on Dundee silt loam in a humid climate to assess soybean growth and yield, weed control, and profitability under no-till conditions in response to (i) no CC (NC), (ii) winter rye CC rolled when green, followed by soybean planting and desiccation by paraquat (GR) and iii) winter rye CC desiccated using paraquat and rolled followed by soybean planting (BR). No differences in phenological growth stages of soybean were observed among the treatments. Measured leaf area index was comparable among the treatments across the three seasons. The rate of rye CC biomass decay estimated eight weeks after planting (WAP) was much higher than at four WAP. In 2019, at eight WAP plant residue ranged from 29.3% under NC to 52.9% under GR, indicating the paraquat desiccated natural winter vegetation decays faster than the desiccated rye CC biomass. The weed biomass was 72% higher at eight WAP (0.29 Mg ha-1) than that of four WAP (0.17 Mg ha-1) and NC plots had higher weed biomass at both four WAP and eight WAP over CC plots. Field established soybean stand in the GR plots were consistently higher than the NC plots by 8%, 30%, and 22% in 2019, 2020, and 2021, respectively. Soybean yield in NC plot was 13% higher than GR and 15% higher than BR plots in 2019. However, in 2020 and 2021, soybean yield from BR and GR plots was significantly higher than NC plots (10% and 13%, respectively). In the three-year study, net returns from soybean with rye CC (regardless of GR or BR) in the first year was negative. In the second and third year, net returns in GR and BR were positive and comparable to NC. There were no differences in soybean yield and net returns between rye CC rolled green (GR) and rye CC desiccated (BR) prior to planting. These results show that a rye CC–based soybean conservation production system could be an economically a viable choice after the first year with an invaluable potential for carbon sequestration, weed suppression and positive impact on summer soybean productivity.

Gypsum and cereal rye cover crops affect soil chemistry: Trace metals and plant nutrients

AbstractWorldwide food security is a pressing concern as population increases. Thus, there is a need to increase food production on existing farmland while improving soil health and water quality. We report the effect of two conservation practices, flue‐gas desulfurization (FGD) gypsum (hereafter “gypsum”) soil amendment and cereal rye (Secale cereale L.) cover crop, on soil chemistry. Emphasis was placed on extractability of trace metals (Cd, Cr, Cu, Ni, and Zn) and plant nutrients (Ca, K, Mg, Mn, Mo, P, and S). Research was conducted under no‐till management for 5 yr at four sites. Treatments consisted of annual gypsum soil surface application (0, 1.1, and 2.2 Mg ha–1), with and without cover crops, and two crop rotations [corn (Zea mays L.)–soybean [Glycine max (L.) Merr.], and continuous soybean]. Soils collected at 0‐to‐15‐ and 15‐to‐30‐cm depths from each treatment at the end of the 5‐yr study were microwave‐digested with 3:1 HNO3/HCl and analyzed for trace metals and nutrients. Gypsum chemical analysis indicated it did not provide trace metals that impair soil/water quality. However, it did provide Ca, S, and other nutrients supporting plant growth. Furthermore, gypsum and cereal rye winter cover crop, relative to the control and under the conditions of this study, did not increase extractability of most trace metals from soils. The cover crop, relative to the control, also significantly decreased P extractability, suggesting cereal rye immobilizes P, potentially decreasing off‐site transport to water bodies. Under the conditions of this study, gypsum and winter cover cereal rye did not increase extractable trace metals.

Site‐specific effects of winter cover crops on soil water storage

AbstractAddition of an overwintering cereal rye (Secale cereale L.) cover crop (CC) to midwestern maize (Zea mays L.)‐based systems offers several environmental benefits, but the long‐term effects of this practice on soil hydrological properties are not well understood. We utilized four long‐term (10+ yr) trials (two commercial fields, two research plots) in Iowa that included a replicated winter rye CC and no‐cover treatment in no‐till maize/soybean [Glycine max (L.) Merr.] systems. We took intact 7.62‐cm diam. soil samples from a 10‐to‐18‐cm depth shortly after cash crop planting in the spring. We measured the soil water retention curve using matric potentials ranging from saturation to –500 cmH2O. In addition, we measured organic matter, textural composition, and bulk densities of the soil samples. At the depth sampled, CCs did not meaningfully affect bulk density, water contents at saturation, or air‐entry potentials at any trial, nor increase the percentage of macropores. At two trials, soil water content at field capacity (–100 cmH2O) in the CC treatments was 2.5 vol% (SE: 1.2%; commercial field) and 2.4 vol% (SE: 1.3%; research plot) higher compared with the no‐cover treatments. This increase could meaningfully reduce the amount of water drained from a field after a saturating rain and should be considered when assessing CC impacts on landscape hydrology. The presence or absence of a CC effect on field capacity was not related to CC aboveground biomass production, previous cash crop, or soil texture at the trial sites. Based on our results, a causal model, and previous literature we hypothesize CC root characteristics are key to understanding variable effects of CCs on soil water storage. Our results indicate it is possible for CCs to meaningfully affect soil water storage, but more research is needed on the mechanisms by which these changes occur.

Influence of Spatial Planting Arrangement of Winter Rye Cover Crop on Corn Seedling Disease and Corn Productivity.

Despite numerous environmental benefits associated with cover crop (CC) use, some farmers are reluctant to include CCs in their production systems because of reported yield declines in corn. There are numerous potential reasons for this yield decline, including seedling disease. A winter rye CC can serve as a "green bridge" for corn seedling pathogens. We hypothesized that proximity of corn seedling roots to decaying rye CC roots contributes to corn seeding disease. An experimental field plot and an on-farm study were conducted over 2 years to evaluate growth, development, and disease severity of corn seedlings planted at various distances from decaying winter rye CC plants. The experimental field plot study was conducted in a no-till corn-soybean rotation with five replications of a winter rye CC treatment seeded as (i) no-CC control, (ii) broadcast, (iii) 19-cm drilled rows, and (iv) 76-cm drilled rows. The on-farm study was no-till corn-soybean rotation with four replications of a winter rye CC seeded as 38-cm drilled rows, 76-cm drilled rows, and no-CC control. The corn was planted on 76-cm rows shortly after rye was terminated. With multiple seeding arrangements of winter rye, corn was planted at different distances from winter rye. Corn radicle root rot severity and incidence, shoot height, shoot dry weight, corn height and chlorophyll at VT (tasseling), ear parameters, and yield were collected. Soil samples were taken in the corn row and the interrow at winter rye termination, corn planting, and corn growth stage V3 (three leaves with fully developed collars) to estimate the abundance of Pythium clade B members present in soil samples. Our results showed that increased distance between winter rye residue and corn reduced seedling disease and Pythium clade B populations in the radicles and soil and increased shoot dry weight, leaf chlorophyll, plant height, and yield. This suggests that physically distancing the corn crop from the winter rye CC is one way to reduce the negative effects of a winter rye CC on corn.