Cover Crop-Based, Organic Rotational No-Till Corn and Soybean Production Systems in the Mid-Atlantic United States

Abstract

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.

The Current State and Future Directions of Organic No-Till Farming with Cover Crops in Canada, with Case Study Support

“…Silva et al recommend fertilization to reach 90-110 kg of available nitrogen per hectare [11]. Meanwhile, a high seeding rate of 134 kg/ha of the common cover crop cereal rye is recommended by Wallace et al to reach 8 tonnes/ha [38]. Halde et al cite recommendations for rye seeding rates ranging from 110 kg/ha to 150 kg/ha [34].…”

“…Rye is shown to have more consistent weed suppression capabilities, reaching 95-98% suppression, than vetch, reaching 71-91% [41]. In organic agriculture, leguminous cover crops are needed to fix nitrogen for the following heavy-feeding cash crop, like corn [38]. When combining rye and vetch for a cover crop, Hayden et al state that at least half the biomass should be contributed by rye in order to effectively suppress winter annual weeds [41].…”

“…Meanwhile, Moyer states that the roller-crimper was designed to avoid a faster decomposition of all cover crops as a result of a lower surface area compared to mowing [9] (pp. [38][39].…”

“…Termination should occur late in the spring, when the cover crop reaches maximum height [9] (p. 93). With warming temperatures, the growth rate also increases, making each extra day of cereal and legume cover crop growth an increasingly larger contribution to the final biomass [9,38] (p. 19). Mirsky et al find that the biomass at termination increases from 7599 kg/ha on May 20 to 10,066 kg/ha on May 30, a greater change than that observed for the earlier 10 day increments [42].…”

“…This method was designed collaboratively at Rodale Institute to achieve a number of goals, unavailable through other termination methods like those employing mowers [9] (pp. [35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50]. The roller-crimper lays down a cover crop neatly and evenly and crushes the mature stems without severing them [9] (p. 44).…”