Winter cover crop performance in the Southern Piedmont region of South Carolina

Cover crops (CCs) offer in-field and environmental benefits when integrated into cropping systems. Low CC adoption in the Southern Piedmont region of South Carolina is partially due to the lack of information on CC performance and benefits within the region. To address this, eight winter CCs and a fallow/pigweed (Amaranthus spp.) treatment were investigated for their influence on soil temperature, volumetric water content (VWC), percent cover, biomass, and the occurrence of soil water repellency (SWR). A randomized complete block design experiment was conducted in the fall and winter of 2021–2022 (EXP A) and repeated in 2022–2023 (EXP B). Experiments were treated separately as methods were revised for EXP B. CCs minimally influenced soil VWC over both experiments with no consistent trend. CC did not influence soil temperatures during EXP A. In EXP B, the fallow/pigweed had the highest soil temperatures on two (out of 10) measuring events (p < 0.05). No SWR was found in either experiment. Establishment and fresh and dry CC biomass were most likely influenced by air temperatures and daylight hours driving germination during days with minimal rainfall. In both experiments, annual rye (Lolium multiflorum) produced cover quickly and yielded high biomass. Crimson clover (Trifolium incarnatum) took longer to establish but also yielded one of the highest biomasses. This study demonstrated that winter CCs had little influence on soil physical properties and that while cereal rye (Secale cereale) is a common CC utilized for erosion control, the greater biomass and surface roots of annual rye make it a superior CC for use in Southern Piedmont agroecosystems.