Cereal Cover Crop Research Articles

Impact of using cover crop on predation slug on corn in Pennsylvania

Farmers in Pennsylvania face a significant obstacle in the form of slug insect management. Aims of this study to determine impact of using cover crop against slug attacks in Pennsylvania. This study collaborated with a Pennsylvania regional no-till farming unit to assign three treatments to each farmer: no crop cover (CA), plastic mulch cover (CP), green rye cereal cover (CRH), and dry rye cereal cover (CRK). The experiment was carried out in May – August in 2023. The use of rye cereal cover crops, both in green and dry form, can also have the potential to reduce slug pests. These plants provide shelter and breeding ground for natural enemies of slugs. Plant residue mulching in conservation farming practices provide an effective and sustainable slug pest management strategy. The use of rye cereal can be a reference for farmers in anticipating slug pests in an environmentally friendly manner.

Integrating cover crops and herbicides for weed control in soybean

Abstract In mid-southern, southeastern, and northeastern U.S. soybean production regions, the evolution of herbicide-resistant weeds has become a significant management challenge for growers. The rising herbicide costs for managing herbicide-resistant weeds are also a growing concern, leading to the utilization of cover crops as an integrated weed management strategy for addressing these challenges. Field experiments were conducted at two locations in Alabama in 2022 to evaluate winter cereal cover crops, including a mixture and herbicide system integration in soybean. Treatments included five cover crops: oats, cereal rye, crimson clover, radish, and a cover crop mixture. Cover crops were evaluated for their weed-suppressive characteristics compared to a winter fallow treatment. Additionally, four herbicide treatments were applied: a preemergence (PRE) herbicide, a postemergence (POST) herbicide, PRE plus POST herbicides, and a nontreated (NT) check. The PRE herbicide was S-metolachlor; the POST treatment contained a mixture of dicamba and glyphosate. The PRE plus POST system contained the PRE application followed by POST application. Results show that cereal rye and the cover crop mixture provided weed biomass reduction compared to all cover crop treatments across both locations. Furthermore, we observed greater soybean yield following the cereal rye cover crop than following the winter fallow treatment at one location. POST and PRE plus POST herbicide treatment resulted in greater weed biomass reduction and improved soybean yield than the PRE herbicide treatment alone and the NT check at both locations.

Effect of vegetational diversification on the gene flow of natural enemies in a plum orchard

Plant diversity strategies promote positive effects on the delivery of ecosystem services by establishing winter refuges and other food resources for populations of natural enemies. Cover crops are encouraged as a sustainable practice able to stimulate the early recruitment of natural enemies. However, there is insufficient evidence of the dispersal of natural enemies between added vegetation habitats and targeted crops in orchards. Here we study the genetic diversity and population genetic structure of a plum aphid parasitoid using microsatellite markers developed specifically for Aphidius platensis. We seek to understand whether parasitoid wasps are able to shift between alternative and target aphid hosts (winter vs. spring hosts) developing on winter oat cover crops, spontaneous vegetation, and the target plum trees in an organic orchard system. Our results supported aspects of our hypotheses by providing evidence that added habitat diversity, through a cereal cover crop, can act as banker plants of parasitoid populations for the dispersion of migrants within a fruit orchard, which could favor suppression efficiency of orchard pests, as well as enable population persistence of parasitoids.

156 Winter Hardy Cereal Cover Crops for Spring Grazing in Nebraska

Abstract Soybean harvest leaves little residue, potentially subjecting the soil to negative environmental impacts. Additionally, integrated livestock producers with crops and cattle identified a need to fill early spring forage deficiencies. Planting winter-hardy cereal cover crops after soybean harvest provides ground cover until the next cash crop is planted and has potential for early spring grazing before perennial pastures are ready. A 3-year study was conducted near Mead, Nebraska to evaluate the grazing potential of winter wheat, winter triticale, and cereal rye when planted after soybean harvest. A 7.3-ha field was split into nine 0.81-h paddocks and paddocks were then randomly assigned to a small cereal species (n = 3 paddocks per treatment), then divided further into 2, 0.4 ha paddocks to allow for rotational grazing within the assigned paddock. Growing steers were stratified by body weight (BW) and randomly assigned to paddock with 6 steers per paddock in years 1 and 2, and 5 steers per paddock in year 3. Steers were limit-fed at 2% of BW to equalize gut fill and weighed before and at the conclusion of grazing. Grazing was initiated when a paddock reached 13 cm. The initial BW did not differ among treatments (P > 0.05) with steers weighing 303, 335, and 372 kg in years 1 through 3, respectively. The final BW did not differ among treatments (P > 0.05). There was a treatment by year interaction (P ≤ 0.01) for average daily gain (ADG). There were no differences (P > 0.05) in ADG among treatments in year 1 (1.9 kg/d) or year 3 (1.3 kg/d). However, in year 2, steers grazing rye gained more (P < 0.01) at 1.4 kg than wheat (0.83 kg) and triticale (0.67 kg), which did not differ (P > 0.05). There were no differences (P > 0.05) among treatments for animal unit months (AUM) per hectare. Year 1 provided the most (P < 0.01) grazing at 5.1 AUM/ha, year 2 provided the least (P < 0.01) at 2.4 AUM/ha, and year 3 was intermediate at 3.1 AUM/ha. For gain per hectare (GPH), there were no differences (P > 0.05) among treatments. Steers in year 1 had greater (P < 0.01) GPH (390 kg/ha) than subsequent years, with year 2 (93 kg/ha) being less (P < 0.01) than year 3 (151 kg/ha). For all 3 years, there were no differences among treatments in pre-graze (P > 0.05) or post-graze biomass (P > 0.05). These data suggest that during early spring there are no major differences in the grazing potential and growing cattle performance for wheat, rye, or triticale in eastern Nebraska.

Using structure-from-motion to estimate cover crop biomass and characterize canopy structure

ContextVariability in biomass production poses a challenge for growers when using cover crops for weed control. However, most methods for assessing cover crop biomass are laborious and impractical on a field scale. ObjectiveThe goal of the present study was to determine the feasibility of using Structure-from-Motion (SfM) photogrammetry to estimate biomass in cereal rye (Secale cereale L.) and winter wheat (Triticum aestivum L.) cover crops by correlating biomass with 3-D point cloud pixel density and crop height. MethodsPoint clouds were generated using a SfM algorithm from RGB (red, green, and blue) videos collected by a hand-held GoPro camera over sixteen crop fields in North Carolina, Iowa, and Maryland, USA, throughout two growing seasons (2021–2023). Crop height, leaf area index (LAI), and photosynthetically active radiation (PAR) were also measured. ResultsBiomass was positively correlated with crop height for both cereal rye (R2 = 0.621) and wheat (R2 = 0.55). LAI was positively correlated with biomass accumulation and crop height for both species, increasing linearly in rye and exponentially in wheat. Conversely, PAR penetration below the canopy decreased with biomass accumulation and crop height in both species, with a more rapid extinction in wheat than rye. Point cloud pixel density showed a positive linear relationship with biomass in rye but saturated after 2.5 tonnes ha−1 (2500 kg ha−1). In wheat, point cloud pixel density was weakly and negatively correlated with biomass due to a denser canopy causing faster saturation of tissue detection by SfM point clouds. However, considering crop height and point cloud density integrating them both in the model allowed obtaining a positive relationship with biomass through levels of 8 tonnes ha−1 (8000 kg ha−1) in both species. When models were validated with independent data, predicted and measured biomass were positively correlated for both rye (R2 = 0.86) and wheat (R2 = 0.78). ConclusionsBased on the results, using SfM to generate 3-D point clouds can provide a more accurate estimation of biomass than canopy height alone by capturing species-level differences in canopy architecture. ImplicationsThe results of this study suggest that SfM can potentially be used as a non-destructive tool for growers to monitor biomass production in cereal cover crops other systems such as energy/forage crops, which can help inform management decisions and conserve resources.

Reaction of Winter Cover Crops to Meloidogyne enterolobii and Glasshouse Bioassay for Evaluating Utility in Managing M. enterolobii in Soybeans.

Meloidogyne enterolobii is an invasive and highly aggressive root-knot nematode pathogen impacting the Southeastern United States. Winter cover cropping may be a cost-effective method for reducing populations of M. enterolobii in between summer cash crops, yet a gap in the knowledge remains about the response of these cover crops to M. enterolobii and their utility in suppressing nematode populations prior to a cash crop. A "two-step" glasshouse bioassay was performed to evaluate eight winter cover crops popular in North Carolina for their direct response to M. enterolobii infection, and to quantify their effect in reducing nematode populations for the following soybean plants. Data on cover crop root galling, soybean root galling, soybean shoot fresh weight, soybean root fresh weight, eggs per gram of soybean root, and a modified reproductive factor were collected. Cereal cover crops did not display root galling, and there was significantly less root galling in those soybean plants following cereal winter cover crops when compared to those following broadleaf winter cover crops. Broadleaf winter cover crops resulted in significantly higher eggs per gram of soybean root and modified reproductive factor in the soybean plants, compared to cereal cover crops and non-inoculated controls. Results from this study suggest that cereal winter cover crops may be poor-hosts to M. enterolobii and may significantly reduce M. enterolobii populations before a soybean crop, compared to broadleaf winter cover crops. This study lays the groundwork for management recommendations and future field trials to assess management of M. enterolobii through winter cover cropping.

Predicting cereal cover crop biomass using shoot length in California vegetable systems

AbstractTo better understand cover crop benefits and receive nitrogen scavenging credits for cover cropping, farmers need simple and robust methods of predicting cover crop biomass production. A new regulation focused on improving nitrogen management on over 200,000 ha of irrigated land in the central coast of California motivated us to evaluate if the shoot length of rye (Secale cereale L., ‘Merced’) and triticale (× Triticosecale Wittmack, ‘Pacheco’) could predict shoot biomass. Field samples for rye (n = 162) and triticale (n = 126) were collected at various developmental growth stages from organic and conventional vegetable farms and planting date trials, across multiple soil types, planting times, row spacings, and plant densities. Main shoot length was well‐correlated with oven‐dry shoot biomass for rye (r2 = 0.87) and triticale (r2 = 0.88). This provides farms in California and beyond with a simple, robust method to estimate cover crop shoot biomass.

Remote sensing evaluation of winter cover crop springtime performance and the impact of delayed termination

AbstractIn 2019, the Maryland Department of Agriculture's Winter Cover Crop Program introduced a delayed termination incentive (after May 1) to promote springtime biomass accumulation. We used satellite imagery calibrated with springtime in situ measurements collected from 2006–2021 (n = 722) to derive biomass estimates for Maryland fields planted to cereal cover crop species (286,200 ha total over two seasons). Cover crop C content remained steady throughout the cover crop growing season (42.6% of biomass), whereas N concentration had an inverse relationship with biomass and ranged from 1.7 to 2.9%. Throughout Maryland, delayed termination fields (n = 19,120; average termination of May 18) were, on average, estimated to accumulate an additional 789 kg of biomass, 15 kg of N, and 336 kg of C per hectare when compared to fields associated with standard termination dates (n = 28,811; average termination of April 16). Over two cover crop seasons (2019–2021), the delayed termination incentive yielded an extra 75,660,000 kg biomass, 1,526,000 kg N, and 32,230,000 kg C across 96,040 hectares. Regularly terminated field incentives cost an average of US$0.10 per kg of biomass and $4.09 per kg of N, with variability associated with agronomic management (species, planting method). Delayed termination fields cost of $0.08 per kg of biomass and $3.51 per kg of N. Late‐planted cover crops that were terminated early had minimal environmental benefit, and wheat, which comprised 68% of cover crop area, performed poorly compared with other cereal species. Our findings demonstrate that substantial additional springtime biomass, C, and N accumulation were achieved through the delayed termination incentive.

​Effect of Legume and Cereal Mulches on Weed Dynamics and Potato Yield

Background: Non-chemical management methods, including cover crops, has an essential role in diminishing weed infestations and reducing the use of herbicides. Methods: To evaluate the suppressive effects of four cover crop options on weed populations, a field experiment was conducted in factorial randomized bock design with three replications at Ardabil Agricultural and Natural Resources Research Station, Ardabil, Iran, in 2016. The treatments consisted of legumes and cereal cover crop as one factor (Control, Rye, Common vetch, Grass pea and Hungarian vetch) and crop management strategies as a second factor [forage use (FU) and land cover use (LCU)]. Result: Grass pea sown as fodder use strategy recorded the highest fresh and dry weight of weeds significantly. The greatest potato yield production was observed in Rye and Hungarian vetch plots, approximately 5000 kg ha-1 in both FU and land LCU strategies. Generally, it seems that Rye and Hungarian vetch could be acceptable options to use in potato production as cover crops.

Plant-Derived Carbon Sources for Anaerobic Soil Disinfestation in Southern California

Anaerobic soil disinfestation (ASD) has been optimized and adopted as an organic alternative to chemical fumigation by strawberry growers in California. The ASD process relies on mixing labile carbon sources into the soil to generate chemical, physical, and microbiological changes aiding suppression of the soil-borne pathogens and enhancing fruit production. Continued ASD adoption is hindered by the increasing cost of rice bran, currently the most widely used carbon source. To address this need and to find suitable and economical alternative carbon sources, we conducted field evaluations of locally produced or sourced plant-based products. ASD with incorporated grass-sod clippings spent grain and coffee grounds from one supplier provided a 47% to 83% increase in fruit yields compared to untreated soil, but coffee grounds from a different supplier decreased strawberry yields. Carbon, nitrogen, and their ratios had important impacts on the efficacy of ASD with coffee grounds and grape pomace. ASD with wheat midds at 20 t/ha provided strawberry yields similar to chloropicrin-fumigated soil while substituting 30% of rice bran carbon rate with on-site grown cereal cover crop biomass resulted in yields similar to the full rate of rice bran but at a reduced cost. As we continue exploring cost-effective methods of soil disinfestation, we utilize ASD integrated with other pest management tools, such as the use of resistant cultivars and crop rotation for sustainable production.

Late-Season Nitrogen Applications Increase Soybean Yield and Seed Protein Concentration.

Low seed and meal protein concentration in modern high-yielding soybean [Glycine max L. (Merr.)] cultivars is a major concern but there is limited information on effective cultural practices to address this issue. In the objective of dealing with this problem, this study conducted field experiments in 2019 and 2020 to evaluate the response of seed and meal protein concentrations to the interactive effects of late-season inputs [control, a liquid Bradyrhizobium japonicum inoculation at R3, and 202 kg ha−1 nitrogen (N) fertilizer applied after R5], previous cover crop (fallow or cereal cover crop with residue removed), and short- and full-season maturity group cultivars at three U.S. locations (Fayetteville, Arkansas; Lexington, Kentucky; and St. Paul, Minnesota). The results showed that cover crops had a negative effect on yield in two out of six site-years and decreased seed protein concentration by 8.2 mg g−1 on average in Minnesota. Inoculant applications at R3 did not affect seed protein concentration or yield. The applications of N fertilizer after R5 increased seed protein concentration by 6 to 15 mg g−1, and increased yield in Arkansas by 13% and in Minnesota by 11% relative to the unfertilized control. This study showed that late-season N applications can be an effective cultural practice to increase soybean meal protein concentration in modern high-yielding cultivars above the minimum threshold required by the industry. New research is necessary to investigate sustainable management practices that increase N availability to soybeans late in the season.

78 Winter Hardy Small Cereal Cover Crops for Grazing and Silage in Nebraska

Abstract Cereal rye, winter wheat, and winter triticale are commonly planted cover crops in corn and soybean systems and have the potential to provide early spring grazing. The three cover crops differ in growth pattern. Therefore, a study was conducted to investigate the grazing potential of the three species, including the timing of the start of grazing and nutritive value of forage as measured by growing calf gain. A 7.3 hectare field was divided into 9, 0.81-hectare paddocks. Three paddocks (n = 3 replicates per treatment) were randomly assigned to each treatment: variety not stated cereal rye, Pronghorn winter wheat, or NT11406 triticale. Pastures were seeded in Mid-September following early maturity soybean harvest and received no fertilizer. Fifty-four steers (305 kg SD ± 5 kg) were stratified by weight and assigned to one of nine groups which were then assigned to a paddock. The paddocks were split in half. Steers were turned out when forage reached a 12.7 cm height and rotated to the other half once the occupied half reached 5 cm. Grazing began April 3 for rye pastures and April 9 for triticale and wheat pastures. Two groups of cattle grazing rye were pulled April 29 due to limited forage. All remaining cattle were pulled May 8 to allow for soybean planting. Throughout the grazing period pre and post-graze biomass did not differ (P ≥ 0.36) among treatments. Average daily gain did not differ among treatments (P = 0.88) averaging 1.79, 1.86, 1.84 kg/day for rye, wheat and triticale, respectively. Likewise, gain per hectare did not differ (P = 0.80) among treatments with 378, 399, 394 kg/ha for rye, wheat, and triticale, respectively. Rye offered grazing a full week before triticale and wheat, but all three small grain cereal species resulted in desirable animal performance.

Digital image analysis estimates of biomass, carbon, and nitrogen uptake of winter cereal cover crops

Over-wintering cereal cover crops contribute to greater cropping system sustainability by reducing risk of erosion, adding carbon (C), and sequestering inorganic nitrogen (N) between fall harvest and spring planting of annual crops. Carbon and N pools can be measured by manual sampling and laboratory analysis of roots and shoots. However, this is expensive and unscalable to field levels. This study aimed to (1) determine relationships between shoot biomass and total biomass, C and N uptake of winter wheat (Triticum aestivumL.), cereal rye (Secale cerealeL.), and triticale (XTriticosecaleWittm.); and (2) develop models to estimate shoot biomass using green cover (%) from digital images. Shoot and root biomass, C, and N uptake of cover cropped fields were determined by destructive sampling within rectangular quadrats (97.8 × 20.3 cm) in fall 2011 prior to snowfall (58 fields) and spring 2012 prior to termination (30 fields). In addition, shoot biomass and digital images (top view of crop canopy taken at shoulder height) were collected in fall 2013 and spring 2012–2014 (266 quadrats) using four different cameras (Canon, Nikon, Apple iPhone, Motorola Droid) for a total of 589 images. Four approaches were evaluated to estimate green cover: (i) estimation from “Canopeo” software; (ii) RGB color space with a set cutoff; (iii) the Lab color space with fixed adjustment of the “a” channel per camera; and (iv) the Otsu thresholding method applied to the “a” channel of the Lab color space. Shoot biomass ranged from 37 to 2657 kg DM ha−1 and was linearly correlated with total biomass (R2 = 0.99), total C (R2 = 0.99), and total N (R2 = 0.92), independent of species or season. The Otsu method best estimated shoot biomass from green cover (R2 = 0.66; green cover ranging from 10 to 70%). This method also reduced differences among cameras and the influence of lighting conditions on green cover estimations. Exponential models for shoot biomass estimation from green cover (%) determined with the Otsu method had the highestR2 for cereal rye (R2 = 0.79), followed by triticale (R2 = 0.54), and wheat (R2 = 0.52). We conclude these models, combined with linear equations to predict total biomass, C, and N uptake from shoot biomass can be used to estimate the same from imagery. Additional research is needed to validate models across more locations, different growth stages, and to expand across a larger range of green coverage.

Scavenging and recycling deep soil nitrogen using cover crops on mid-Atlantic, USA farms

In the mid-Atlantic USA region, nitrogen uptake by crops ceases about four weeks prior to harvest maturity, leaving substantial mineral N in the soil profile, which is prone to leach during the winter. Deep-rooted cover crops planted by early-September can potentially take up residual N and recycle some of it for following cash crops. We performed experiments on 19 minimum-tillage, grain farms investigating four unfertilized cover crop systems (forage radish (Raphanus sativus L.), winter cereal or grass, forage radish + winter cereal + crimson clover (Trifolium incarnatum L.), and a no cover crop control). We measured cover crop biomass, N uptake, and inorganic N distribution within the upper 210 cm of soil in late-fall and early-spring, and the following corn (Zea mays L.) crop’s growth and yield. In late-fall, radish reduced soil NO3 in the upper 90 cm by 66 %, while winter cereal or mix cover crops reduced NO3 in the upper 60 cm by 67 % and 56 %, respectively, compared to a no cover crop control. In the spring, the radish and mix cover crops resulted in comparable nitrate levels to the no cover crop control in the topsoil layer (> 30 kg ha−1) and less nitrate than the no cover crop control in subsoil layers. The winter cereal cover crop had low nitrate levels in the topsoil (∼20 kg ha−1) layer and subsoil layers. The biomass and N content of corn seedling (5 leaf) were influenced by the previous cover crop treatment in the order radish (4.0 g biomass plant−1) > mix (3.0 g biomass plant−1) = control (3.5 g biomass plant−1) > winter cereal (2.4 g biomass plant−1). At the farmers’ standard N fertilizer application rate, corn yield following radish was higher than following the winter cereal or mixed species cover crop but corn yield following radish was not different than following no cover crop. Corn yield following the winter cereal cover crop was lower than following no cover crop. Cover crops can be fit within the framework of existing cropping systems to scavenge residual N, therein reducing subsoil inorganic N. Radish and mixed species cover crops can be used prior to corn without reducing the overall short-term N use efficiency of the cropping system.

Assessing synergistic effects of no-tillage and cover crops on soil carbon dynamics in a long-term maize cropping system under climate change

Climate-smart agriculture management practices such as no-tillage (NT) and cover crops (CCs) have been widely applied and are expected to offer multiple environmental benefits (e.g., soil carbon sequestration, yield stability, and climate resilience). However, the long-term effects of these management practices, especially their synergistic interaction, have not been well addressed. This study used an improved agroecosystem model (DLEM-Ag) to explore the synergistic effects of NT and CCs on soil carbon dynamics in a continuous maize system in the middle south of the United States for 1970–2099. Simulation results for 1970–2018 show that NT, relative to conventional tillage (CT), led to carbon gains (0.22 Mg C ha−1 yr−1) in the topsoil in a CC-inclusive continuing maize system; however, NT per se brought minor net carbon gains. This well captures the field observations. Model factorial analyses reveal that soil carbon sequestration was highly correlated with biomass carbon inputs from both the winter cereal CC and the summer maize. Elevated CO2 and warming effects were the main contributors to soil carbon gains, as these promote CC growth. Further model projections suggest that soil organic carbon would increase in the RCP 8.5 future scenarios (2019–2099), with greater gains under NT-CCs than under CT-CCs (0.089 vs. 0.058 Mg C ha−1 yr−1), largely due to enhanced CC biomass production. Moreover, NT-CCs would reduce carbon loss compared to CT-CCs (-0.002 vs. -0.017 Mg C ha−1 yr−1) in the RCP 2.6 scenarios. Our study highlights the importance of CCs in enhancing cropland carbon sequestration and indicates that NT and CCs, taken together, can serve as a viable strategy to ensure crop production through promoting soil health in similar maize cropping systems.

Suitability and Profitability of a Cereal Aphid for the Parasitoid Aphidius platensis in the Context of Conservation Biological Control of Myzus persicae in Orchards.

The use of cover crops can promote the abundance and early arrival of populations of natural enemies. Cereal cover crops between orchards rows could encourage the early arrival of the parasitoid Aphidius platensis, as they offer alternative winter hosts (e.g., Rhopalosiphum padi), enhancing the control of Myzus persicae in spring. However, the preference for and suitability of the alternative host must be addressed beforehand. To evaluate the potential of this strategy, we assessed host preference using behavioural choice tests, as well as no-choice tests measuring fitness traits, when developing on both host species. One source field for each aphid population from the above hosts was chosen. There was a clear choice for R. padi compared to M persicae, independently of the source, probably due to more defensive behaviours of M. persicae (i.e., kicks and escapes). Nevertheless, both aphid species were suitable for parasitoids’ development. The female progeny developed on R. padi were larger in size, irrespective of their origin. According to our results, in peach orchards with cereals sown between peach trees during the autumn, where we expect when R. padi populations will no longer be available during spring, A. platensis should be able to switch to M. persicae.

Annual Cereal Cover Crops Following Winter Wheat Produce High Quality Fall Forage

Core Ideas Forage quality of fall‐grown annual cereal cover crops was high in southern Ontario, Canada.Oat produced more forage than barley when disease pressure was high.Oat–pea forage had higher crude protein with similar yield and nutrient digestibility versus oat.Fertilization (50–67 kg N ha−1) increased yield without affecting quality.Oat seeded at 80 and 120 kg ha−1 had similar forage yield and quality. Fall‐grown cereal cover crops can serve dual purpose as forage in southwestern Ontario, Canada. Four experimental field trials and four on‐farm validation trials were conducted to evaluate yield and quality of late‐summer sown and fall harvested barley (Hordeum vulgare L.), oat (Avena sativa L.), and an oat–pea (Pisum sativum L.) mixture. Barley, oat, and the oat–pea mixture had similar yields where 50 to 67 kg N ha−1 was applied and when barley yields were not limited by Septoria (Septoria passerinii Sacc) leaf spot. Forage yields were increased at three of four experimental field trials by 0.3–0.7 Mg ha−1) when harvest was delayed from late October to mid‐November. Later harvest dates increased nonfiber carbohydrates (NFC) (51–99 g kg−1) and decreased neutral detergent fiber (NDF) (16–54 g kg−1) and crude protein (CP) (19–47 g kg−1) with minimal effect on total digestible nutrients (TDN). Mid‐fall harvested oat forage with 50 to 67 kg N ha−1 produced an average yield of 2.9 Mg ha−1. Oat forage quality was consistently high. Individual trial oat averages for NDF did not exceed 509 g kg−1, in‐vitro neutral detergent fiber digestibility (NDFD) was not less than 690 g kg−1, increased NFC was not less than 285 g kg−1 and TDN always exceeded 720 g kg−1. Addition of peas, increased CP by 28 g kg−1, with minimal impact on other nutritional quality characteristics. Oat or oat–pea mixtures, seeded as cover crops following winter cereal harvest are capable of producing satisfactory forage yields with excellent nutritional quality.

Oat, rye, and ryegrass response to nitrogen fertilizer

A cereal cover crop combined with conservation tillage can enhance soil productivity of degraded Southeastern soils. This experiment, conducted in Headland, AL, was designed to compare cover crop biomass performance across nitrogen rates during the 2009 to 2012 growing seasons. Earn 1 CEU in Nutrient Management by reading this article and taking the quiz at www.certifiedcropadviser.org/education/classroom/classes/694.

Mycorrhiza-mediated interference between cover crop and weed in organic winter cereal agroecosystems: The mycorrhizal colonization intensity indicator.

The mycorrhizal fungi are symbiotic organisms able to provide many benefits to crop production by supplying a set of ecosystem functions. A recent ecological approach based on the ability of the fungi community to influence plant–plant interactions by extraradical mycelium development may be applied to diversified, herbaceous agroecosystems. Our hypothesis is that the introduction of a winter cereal cover crop (CC) as arbuscular mycorrhizal fungi (AMF)–host plant in an organic rotation can boosts the AMF colonization of the other plants, influencing crop–weed interference. In a 4‐years organic rotation, the effect of two winter cereal CC, rye and spelt, on weed density and AMF colonization was evaluated. The AMF extraradical mycelium on CC and weeds roots was observed by scanning electron microscopy analysis. By joining data of plant density and mycorrhization, we built the mycorrhizal colonization intensity of the Agroecosystem indicator (MA%). Both the CC were colonized by soil AMF, being the mycorrhizal colonization intensity (M%) affected by environmental conditions. Under CC, the weed density was reduced, due to the increase of the reciprocal competition in favor of CC, which benefited from mycorrhizal colonization and promoted the development of AMF extraradical mycelium. Even though non‐host plants, some weed species showed an increased mycorrhizal colonization in presence of CC respect to the control. Under intense rainfall, the MA% was less sensitive to the CC introduction. On the opposite, under highly competitive conditions, both the CC boosted significantly the mycorrhization of coexistent plants in the agroecosystem. The proposed indicator measured the agroecological service provided by the considered CCs in promoting or inhibiting the overall AMF colonization of the studied agroecosystems, as affected by weed selection and growth: It informs about agroecosystem resilience and may be profitably applied to indicate the extent of the linkage of specific crop traits to agroecosystem services, contributing to further develop the functional biodiversity theory.

Winter Cereal Cover Crops for Spring Forage in Temperate Climates

Core Ideas Barley is not a suitable cover or forage crop for southern Ontario due to winter‐kill. Flag leaf, boot, and heading of cereal rye are about 1 wk earlier than for wheat or triticale. Forage quality of winter cereals was high from flag leaf to boot stages. Nitrogen fertilization (50–67 kg N ha−1) optimized forage yield without affecting quality. In this study four winter cereals commonly used as cover crops were evaluated for forage yield potential and nutritional quality when harvested in early spring. Wheat (Triticum aestivum L.), triticale (X Triticosecale Wittm.), cereal rye (Secale cereale L.), and barley (Hordeum vulgare L.) were evaluated via experimental plots and on‐farm trials in southern Ontario, Canada, between 2013 and 2015. Barley was the only species that failed to overwinter. The average forage yield of all other winter cereal species was 2.9 Mg ha−1 dry matter (DM) at boot stage with total digestible nutrient (TDN) values above 700 g kg−1 at flag leaf and boot stages of development. At the flag leaf and boot stages of development the fiber content of cereal rye was higher and nonfiber carbohydrates lower than wheat or triticale. However, crude protein (CP) and TDN were indistinguishable among species. Across species and experimental plot site‐years, a spring N application of 50 kg N ha−1 increased forage yield by 0.9 Mg ha−1 DM and CP by 26 g kg−1, but all other quality parameters were unaffected. Additional N fertilization, on‐farm, increased DM yield, but economically optimum N rates remained low, at 42, 50, and 65 kg N ha−1 for cereal rye, triticale, and wheat, respectively. While wheat and triticale may be used as spring forage, the approximately 7d earlier flag leaf or boot stage of cereal rye makes it a better fit for rotations with corn (Zea mays L.) and soybean [Glycine max (L.) Merr].