Long-Term Corn Residue Grazing Improves Subsequent Soybean Yields in a Corn-Soybean Rotation
Drewnoski, M.E.; MacDonald, J.C.; Erickson, G.E.; Hanford, K.J.; Klopfenstein, T.J.
Crop Forage and Turfgrass Management 2(1)
ISSN/ISBN: 2374-3832 DOI: 10.2134/cftm2015.0192
A 90-acre irrigated field was utilized in which half of the field was planted to corn (Zea mays L.) and the other half was planted to soybeans [Glycine max (L.) Merr.], and crops were alternated yearly. Each half was divided into two replicates of three treatments in which corn residue was: fall/winter grazed (FG) November to February (similar to 90 days), spring grazed (SG) February to mid-April (similar to 70 days), and not grazed (NG). Calves (500-700 lb body weight) were stocked at 1.2 head/acre in FG throughout the trial and in SG for 5 years, then stocking rate was increased to 3 head/acre in SG. For FG, no-till planting was utilized. Within SG and NG, three tillage treatments, no-till, ridge-till, or spring-disk-till, were imposed after corn, with no-till following soybeans. These tillage treatments were maintained for 9 years, after which only the no-till was continued for 7 more years. For both corn and soybean yields, no interaction (P >= 0.55) between tillage and grazing occurred over the 9 years. Across all tillage treatments, SG increased (P < 0.01) soybean yields over NG (58.5 and 57.0 bu/acre, respectively) and had no effect (P = 0.58) on corn yields. On land managed under no-till throughout the trial, FG (65.5 bu/acre) improved (P < 0.01; SEM = 0.54) and SG (63.5 bu/acre) tended (P = 0.07) to improve soybean yields over NG (62.1 bu/acre), and FG tended (P = 0.07; 211 bu/acre) to improve corn yield over NG (207 bu/acre) while SG (209 bu/acre) did not differ (P = 0.27) from NG. These data suggest that grazing of corn residue at stocking rates that would result in consumption of 10 to 22% of the residue appears to have slightly positive or no impacts on subsequent soybean or corn yields.