Winter grazing does not affect soybean yield despite lower soil water content in a subtropical crop-livestock system
Commercial-scale integrated crop-livestock systems intensify land use by combining complementary agricultural enterprises and leveraging synergistic ecosystem services to achieve both productive and environmental outcomes. Although widely implemented in southern Brazil as an annual beef/soybean rotation, tradeoffs such as competing soil water use between pasture and crop phases may result from seasonal grazing in this system. We compared soil water and plant physiological variables in the crop phase of an integrated annual beef-soybean system managed with no-till and best grazing practices with those of an ungrazed cover crop control as part of a long-term experiment in southern Brazil. A mixed black oat (Avena strigosa Schreb.) and Italian ryegrass (Lolium multiflorum Lam.) pasture was either grazed by beef cattle to 20-cm sward height or left as an ungrazed cover crop in the winter, and direct-planted to soybean (Glycine max [L.] Merr.) in the summer. Although soybean yields did not differ between grazed and ungrazed treatments, soil matric potential was on average 25% lower across depths and growth stages in plots that had been grazed during winter. Soybeans in grazed plots also exhibited up to 34% lower light-use efficiency and a 2-week slower time to physiological maturation than soybeans in plots that had not been previously grazed. These results describe for the first time the differential crop growing conditions and crop physiological responses created after 16 years of integration with grazing animals. As integrated crop-livestock systems grow in importance in commercial production settings, this research can inform adaptive management practices to ensure the sustainability of these systems into the future and under a variety of environmental conditions.
KeywordsIntegrated crop-livestock systems Soil water Normalized difference vegetation index Photochemical reflectance index Leaf water potential Soybean Glycine max Crop physiology
The authors thank M. Gilbert for helpful comments on a draft of the manuscript, the Garcia de Garcia family and farm staff at Agropecuária Cerro Coroado for their longstanding support of the São Miguel das Missões experimental station at Espinilho Farm, and Augusto Caetano, Gleice Menezes, Angel Zubieta, Natascha Grinnell, Rodrigo Michaovski, Vicente Padilha, Jonatas Silva, Gustavo Heissler, Júlio Azambuja, Naihana Schaffer, Débora Rubin, and Mateus Soldera for their invaluable assistance in the field and laboratory.
This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant No. (1650042, P Mohapatra), an international travel allowance through the CAPES-NSF Graduate Research Opportunities Worldwide program to CP, and by the USDA National Institute of Food and Agriculture Agricultural Experiment Station Hatch Projects to AG (project CA-D-PLS-2332-352H).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.
- Assmann JM, Anghinoni I, Martins AP, Costa SEVGA, Cecagno D, Carlos FS, Carvalho PCF (2014) Soil carbon and nitrogen stocks and fractions in a long-term integrated crop-livestock system under no-tillage in southern Brazil. Agric Ecosyst Environ 190:52–59. https://doi.org/10.1016/j.agee.2013.12.003 CrossRefGoogle Scholar
- Caetano LAM (2017) Impacto da intensidade de pastejo na produtividade da soja em integração com bovinos de corte. Universidade Federal do Rio Grande do SulGoogle Scholar
- Cecagno D, Costa SEVG de A, Kunrath TR et al (2017) Soil and pasture water status in a long term integrated crop-livestock system perspective. Rev Bras Tecnol Agrop 1:24–34Google Scholar
- CONAB (2017) Acompanhamento da safra brasileira de grãos: Séries históricasGoogle Scholar
- Foley JA, Ramankutty N, Brauman KA, Cassidy ES, Gerber JS, Johnston M, Mueller ND, O’Connell C, Ray DK, West PC, Balzer C, Bennett EM, Carpenter SR, Hill J, Monfreda C, Polasky S, Rockström J, Sheehan J, Siebert S, Tilman D, Zaks DPM (2011) Solutions for a cultivated planet. Nature 478:337–342. https://doi.org/10.1038/nature10452 CrossRefPubMedGoogle Scholar
- Kunrath TR, Cadenazzi M, Brambilla DM, Anghinoni I, Moraes A, Barro RS, Carvalho PCF (2014) Management targets for continuously stocked mixed oat x annual ryegrass pasture in a no-till integrated crop-livestock system. Eur J Agron 57:71–76. https://doi.org/10.1016/j.eja.2013.09.013 CrossRefGoogle Scholar
- Martins AP, Anghinoni I, Costa SEVG d A et al (2014a) Amelioration of soil acidity and soybean yield after surface lime reapplication to a long-term no-till integrated crop-livestock system under varying grazing intensities. Soil Tillage Res 144:141–149. https://doi.org/10.1016/j.still.2014.07.019 CrossRefGoogle Scholar
- Mott G, Lucas H (1952) The design, conduct, and interpretation of grazing trials on cultivated and improved pastures. In: Proc 6th Int Grassland Cong, Pennsylvania 1380–1385Google Scholar
- Silva IR, Smyth TJ, Raper CD, Carter TE, Rufty TW (2001) Differential aluminum tolerance in soybean: an evaluation of the role of organic acids. Physiol Plant 112:200–210. https://doi.org/10.1034/j.1399-3054.2001.1120208.x CrossRefPubMedGoogle Scholar