Single and Multispecies Cover Crop Effects on Corn Production and Economic Returns

The adoption of cover crops (CCs) has gained popularity in the continuous corn (Zea mays L.) production system due to their multiple benefits including scavenging or fixing nitrogen (N) in the soil. However, a CC's ability to develop early cover, scavenge N, and provide N to the following cash crop is species-dependent and affected by environment. A field study was conducted in three diverse environments to determine growth characteristics of nine CC treatments (i.e., monocultures or mixes of grasses, legumes, and brassica), and their effect on the following corn crop was compared to no cover crop treatment (noCC). Cover crops significantly differed for above-ground biomass, plant tissue carbon (C) and N concentrations, carbon to nitrogen ratio (C/N), and total N uptake (TNU). Among monocultures, grasses had the highest biomass and C/N ratio, and legumes had the highest N concentrations and TNU. Corn grain yield was highest following radish, whereas lowest corn yield was found following cereal rye + crimson clover mix in environment 1. Cover crops varied for C/N ratios in all three environments, but only affected corn plant height (PH) and grain yield in one environment. Cover crops belonging to the same species also exhibit different responses for characteristics measured, depending upon the environment. The expected returns were also variable, especially in CC mixes. The study provides valuable information on the species-specific functionality of CCs in continuous corn under variable environmental conditions. The information will benefit future studies to explore a high diversity mixture of CCs that may outperform across all three environments.