Grazing management effects on cover crop responses and cotton lint yield

Authors: SANTOS, ERICK - University Of Alberta; DUBEUX, JOSE - University Of Florida; SOLLENBERGER, LYNN - University Of Florida; MACKOWIAK, CHERYL - University Of Florida; WRIGHT, DAVID - University Of Florida; DILORENZO, NICOLAS - University Of Florida; SIQUEIRA, MICHELLE - Federal Rural University Of Pernambuco; GARCIA, CARLOS - Federal Rural University Of Pernambuco; QUEIROZ, LUANA - University Of Florida; VAN CLEEF, FLAVIA - Universidad De Sao Paulo; GARCIA, LIZA - University Of Florida; Jaramillo, David; RUIZ-MORENO, MARTIN - University Of Florida

Submitted to: Crop Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2022
Publication Date: 9/9/2022
Citation: Santos, E., Dubeux, J., Sollenberger, L., Mackowiak, C., Wright, D., Dilorenzo, N., Siqueira, M., Garcia, C., Queiroz, L., Van Cleef, F., Garcia, L., Jaramillo, D.M., Ruiz-Moreno, M. 2022. Grazing management effects on cover crop responses and cotton lint yield. Crop Science. 2022:1-14. https://doi.org/10.1002/csc2.20766.
DOI: https://doi.org/10.1002/csc2.20766

Interpretive Summary: Cover crops are beneficial for improving land-use efficiency and diversification, which is important for increasing resiliency of agricultural enterprises to market fluctuations. This study investigated how grazing intensity affects cover crop forage responses and subsequent cotton lint yield, in integrated crop-livestock systems. Cover crops were rye -oat mixture managed as follows: no grazing + 34 kg N ha-1, no grazing + 90 kg N ha-1, heavy grazing, moderate grazing, and light grazing, compared with a no cover crop control. Cotton lint yield was not affected by cover crop inclusion, grazing management, or cover crop N-fertilizer application. Less intensive grazing of cover crops resulted in greater herbage accumulation, compared to heavy grazing. Greater weed presence was observed when heavy grazing was imposed as a result of reduced soil cover. Grazing rye-oat cover crops at moderate intensities appears to be an option for increasing land-use efficiency during cotton off-season without negatively affecting cotton lint yields.

Technical Abstract: Grazing 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 mixture of rye (Secale cereale L.)-oat (Avena sativa L.) 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 post-grazing herbage mass (HM) for HG, MG, and LG was 520, 1350, and 2120 kg DM 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 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 DM ha-1). Heavy grazing resulted in greater weed proportion (17 vs. 6.5%) and lesser soil cover (49 vs. 70%) than non-grazed 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 this 3-yr study, HG reduced soil cover and increased weed presence.