Fallow replacement cover crops in a semi-arid High Plains cropping system

Replacing portions of fallow between sorghum [Sorghum bicolor (L.) Moench] harvest and wheat (Triticum aestivum) planting with cover crops provides opportunity to increase productivity and profitability in dryland winter wheat-sorghum-fallow (WSF) cropping systems. The objective of this study was to identify potential spring fallow replacement cover crops and management to optimize productivity and resource use efficiency of a WSF system. The study was conducted 2013-2018 at Garden City, KS. Three crop rotation phases (WSF, SFW, and FWS) were the main plot, and fallow replacement cover crops were the sub plot. Cover crop treatments were further split into hayed and cover crop left standing groups to estimate forage potential. Results showed precipitation utilization and storage efficiency (PUtSE) increased by 146% for grain cover crop, 50% for cover crop hayed, and 38% for cover crop left standing compared with fallow. Available soil water at wheat planting (ASWP(ww)) was not different between cover crop left standing and fallow. Spring triticale [xTriticosecale Wittm. ex A. Camus (Secale x Triticum)] had up to 182% more forage accumulation over other forage cover crops and a 108% grain yield advantage over other grain cover crops. Our findings showed fallow replacement, forage-hayed, and grain cover crops have a greater PUtSE than fallow which may increase economic returns if subsequent crop yields are not reduced. Cover crops left standing had a moderate PUtSE advantage and similar ASWP(ww) compared to fallow, and cover crop left standing, or fallow would be the best choice if the production goal is to maximize ASWP(ww) and subsequent crop yields.