Grazing management effects on cover crop responses and cotton lint yield

Abstract

AbstractGrazing cover crops can improve land‐use efficiency and diversification, making agricultural enterprises more resilient to market fluctuations. We investigated how grazing intensity affects cover crop forage responses and cotton (Gossypium hirsutum L.) lint yield. Cover crops were a rye (Secale cereale L.)–oat (Avena sativa L.) mixture managed as follows: no grazing + 34 kg N ha–1 (NG34), no grazing + 90 kg N ha–1 (NG90), heavy grazing (HG), moderate grazing (MG), and light grazing (LG), compared with a no cover crop control. All grazed treatments received 90 kg N ha–1. Average postgrazing herbage mass (HM) for HG, MG, and LG was 520, 1,350, and 2,120 kg dry matter ha–1, respectively. Herbage accumulation (HA) rate was greater for LG than HG, with MG being intermediate. Forage crude protein (CP) and in vitro digestible organic matter (IVDOM) concentrations decreased as the season progressed and were usually greater for HG than MG and LG. Stubble residue before cover crop termination was greatest for NG34 and NG90 in 2018 and 2020, however, in 2019 NG90 had greater stubble residue before termination than NG34 (7540 vs. 6650 kg dry matter ha–1). Heavy grazing resulted in greater weed proportion (17 vs. 6.5%) and lesser soil cover (49 vs. 70%) than nongrazed cover crops. Cotton lint yield was low and unaffected by treatment, reaching a maximum of 520 kg ha–1 in 2019. Although lint yield was not affected by cover crop fertilization or grazing during 3 yr, HG reduced soil cover and increased weed presence.