Cover crop-based, organic rotational no-till (CCORNT) corn and soybean production is becoming a viable strategy for reducing tillage in organic annual grain systems in the mid-Atlantic, United States. This strategy relies on mechanical termination of cover crops with a roller-crimper and no-till planting corn and soybean into cover crop mulches. Here, we report on recent research that focuses on integrated approaches for crop, nutrient and pest management in CCORNT systems that consider system and regional constraints for adoption in the mid-Atlantic. Our research suggests that no-till planting soybean into roller-crimped cereal rye can produce consistent yields. However, constraints to fertility management have produced less consistent no-till corn yields. Our research shows that grass-legume mixtures can improve N-release synchrony with corn demand and also improve weed suppression. Integration of high-residue inter-row cultivation improves weed control consistency and may reduce reliance on optimizing cover crop biomass accumulation for weed suppression. System-specific strategies are needed to address volunteer cover crops in later rotational phases, which result from incomplete cover crop termination with the roller crimper. The paucity of adequate machinery for optimizing establishment of cash crops into thick residue mulch remains a major constraint on CCORNT adoption. Similarly, breeding efforts are needed to improve cover crop germplasm and develop regionally-adapted varieties.

Core Ideas Cover crops were successfully established in corn with a drill interseeder.Cover crop biomass production varied notably across the mid‐Atlantic region.Spring cover crop biomass was often proportional to fall cover crop performance.Interseeding cover crops at corn growth stages V2–V3 decreased corn grain yields.Interseeding cover crops at or after corn V4 did not affect corn grain yield. Cover crop adoption remains low in the mid‐Atlantic United States despite potential conservation and production benefits. The short growing season window after corn (Zea mays L.) is a primary limiting factor. A high‐clearance grain drill was recently developed to allow for cover crop interseeding into standing cash crops. Experiment 1 tested the viability of drill interseeding cover crops into corn at the V5 growth stage across multiple locations. Experiment 2 tested interseeding timing (V2–V6 corn growth stage) on corn yield in Pennsylvania. At 16 locations throughout Maryland, Pennsylvania, and New York, we evaluated cover crop fall and spring biomass and the effect on corn yield. Cover crop treatments included annual ryegrass [Lolium perenne L. ssp. multiflorum (Lam.) Husnot]), a mixture of legume species, and an annual ryegrass–legume mixture. Each cover crop treatment successfully established across locations yet was highly variable. Across locations, annual ryegrass–legume mixture produced the highest mean aboveground biomass in fall and spring. Spring biomass of interseeded cover crops generally increased compared with fall biomass. Interseeded cover crops did not affect grain yields of the host corn crop during the year of establishment across locations. Experiment 2 indicated that cover crops interseeded before the V3 growth stage reduced corn grain yields. We recommend interseeding at or after V4 to prevent competition with corn. Our results highlight the viability of drill‐interseeding as a strategy for increasing cover crop adoption.

EAGESTAD INRACover crops play an important role in agricultural sustainability. Unlike commodity cash crops, however, there has been relatively little cover crop breeding research and development. We conducted an online survey to evaluate: (a) the perspectives of organic and conventional farmers in the USA who use cover crops and (b) the specific cover crop traits that are important to farmers. We recruited participants from both organic and conventional agriculture networks and 69% of respondents reported that they farmed organic land. In addition to demographic data and information on management practices, we quantified farmer perspectives on four winter annual cover crops: (1) Austrian winter pea, (2) crimson clover, (3) hairy vetch and (4) cereal rye. Overall, respondents represented a wide range of states, farm sizes, plant hardiness zones and cash crops produced. Of the 417 full responses received, 87% of respondents reported that they used cover crops. The maximum amount farmers were willing to spend on cover crop seed varied by farmer type: 1% of conventional farmers versus 19% of organic farmers were willing to spend over US$185 ha−1 (US$75 acre−1). Organic and conventional farmers differed in terms of the reasons why they grew cover crops, with organic farmers placing greater value on the ecosystem services from cover crops. More organic (63%) than conventional (51%) farmers agreed that participatory breeding was important for cover crop variety development (P = 0.047). Both groups shared strong support for cover crop research and considered many of the same traits to be important for breeding. For the legume cover crops, nitrogen fixation was considered the most important trait, whereas winter hardiness, early vigor, biomass production and weed suppression were the most important traits for cereal rye. Our results illustrate common interests as well as differences in the perspectives between organic and conventional farmers on cover crops and can be used to inform nascent cover crop breeding efforts

Agroecosystem services from cover crop mixtures are linked to aboveground biomass and total N content (kg ha-1). Reported values in the literature, however, vary for aboveground biomass and total N content of cover crop mixtures compared with monocultures. We conducted a meta-analysis using results from 55 site-years from 21 studies conducted in the United States to examine biomass and N content of hairy vetch (Vicia villosa Roth)-cereal rye (Secale cereale L.) mixtures compared with respective monocultures. Overall, hairy vetch-cereal rye mixtures produced 63 and 21% more biomass compared with hairy vetch and cereal rye monocultures, respectively. The N content of hairy vetch-cereal rye mixtures was 150% greater than that of cereal rye monocultures. When the proportion of hairy vetch seeds (by weight) exceeded 46% of the mixture, the mixtures accumulated equivalent or more N than the greatest yielding monocultures (usually hairy vetch). Compared with monocultures, a more consistent positive response of mixtures on biomass and N content was found on coarse-textured soils and following corn (Zea mays L.) rather than soybean [Glycine max (L.) Merr.] harvest. With increasing growing degree days (GDD), the biomass and N content of mixtures decreased relative to hairy vetch monocultures but increased relative to cereal rye monocultures, suggesting better performance of hairy vetch at higher GDD. We conclude that hairy vetch-cereal rye mixtures can produce equivalent or more biomass than both monocultures and accumulate as much N as hairy vetch, and that the relative productivity of mixtures depends on soil type, previous crop, seeding proportion, and GDD.