Effects of Interseeding Cover Crops into Corn and Soybean on Biomass Production, Grain Yields and Ecosystem Services: A Review

Abstract

Planting cover crops can improve soil health and help to sustain agricultural crop yields. In northern climates where corn (Zea mays L.) and soybean (Glycine max L.) are grown, cover crop biomass production can be low. This has led to people investigating the potential of interseeding cover crops into the growing main crop. This paper sought to determine biomass production and the benefit to grain yields, weed control and soil properties from interseeding cover crops into corn and soybean. This review included 70 studies published prior to 15 March 2024. Interseeded cover crops that were winter-hardy such as cereal rye (Secale cereale L.) produced more biomass in the spring (1.04 Mg ha−1 average biomass production) than any of the interseeded cover crops did in fall (0.35 Mg ha−1 average biomass production), primarily at crop row spacings of 76 cm. Factors that affected cover crop biomass production were crop stage, planting method, tillage practice, irrigation and row spacing. There was not a consistent widely planted cover crop species that produced the most biomass. Interseeded cover crops reduced weed biomass by 46% compared to weed control and generally did not affect crop grain yields when planted after V4 crop stage. Interseeded cover crops reduced soil nitrate concentration but generally did not affect other soil properties including soil water content. However, most of these studies planted cover crops at the same site for less than three years. Early interseeded cover crops generally did not perform better than interseeded winter-hardy cover crops planted around crop physiological maturity.