Diversified crop, forage, and livestock systems are assumed to be more sustainable and economically competitive than traditional cropping systems. Objectives of this study were to determine effects of integrating grazing livestock into corn (Zea mays)-soybean (Glycine max (L.) Merr.) (C-S) and corn-soybean-wheat (Triticum aestivum L.) (C-S-W) cropping systems on plant population, grain yield, soil nutrients and soil carbon dioxide (CO2) flux following winter grazing corn residue (both systems) and an oat (Avena sativa) cover crop (C-S-W only) planted after wheat. For the 2019 and 2020 production seasons, neither corn nor soybean plant populations were different in the grazed or non-grazed treatments for the C-S and C-S-W rotations. During 2021 in the C-S rotation, soybean plant populations were greater (P \u3c 0.05) in the grazed corn residue treatment (319,556 plants ha-1) compared to the non-grazed corn residue treatment (286,520 plants ha-1). Despite observed differences in soybean plant population in this year, grazing corn residue and the oat cover crop had no impact on grain yield of soybean or corn in C-S or C-S-W or wheat grain yield in C-S-W. Similarly, for both cropping systems, soil nutrients and CO2 flux did not differ for either the grazed or non-grazed corn residue or the oat cover crop in any year of the study. To date, this partial evaluation of livestock grazing effects on grain yield suggested minimal to no reduction in plant populations in cropland grazed during winter with no apparent negative effects on either grain production or soil nutrients and CO2 flux.
Advisor: Daren Redfear
