Cover crop and termination date effects on wheat forage biomass, nutrient content, and profitability

Abstract

Cover crops are being encouraged due to benefits to soil health and ecosystem services, but they could negatively affect subsequent forage production and system profitability in regions with limited water availability. The objectives of this study were to determine the effects of cover crop treatment and termination date on wheat ( Triticum aestivum L.) forage biomass, crude protein, and total digestible nutrients, and to determine the cover crop/wheat forage production system that was most profitable. Data collected were from a 4‐year (2017–2021) randomized complete block design agronomic study conducted in south‐central Oklahoma. The experiment included two summer fallow treatments as controls and seven summer cover crop treatments (each divided into either early or late termination) for a total of 16 production systems. A mixed‐effects regression model indicated that the choice of summer cover crop had no effect ( p = 0.23) on wheat forage biomass, but early termination significantly increased wheat forage biomass compared to late termination ( p = 0.0001). Effects of cover crop treatment and termination date on crude protein and total digestible nutrients were not significant. The no‐till summer fallow production system had the highest relative net return, equal to $67 ha ⁻¹ . Cover crop systems, compared to the no‐till fallow control, were not profitable because they were costly to establish and provided little to no yield boost. Early cover crop termination increased forage yield, but not enough to make cover crops profitable relative to no‐till fallow. Results suggest cover crops are unlikely to be widely adopted in water‐limited wheat systems in the Southern Great Plains.