Cover crop grazing impacts on soil properties and crop yields under irrigated no-till corn-soybean management

Cover crop (CC) grazing can be a strategy to reintegrate livestock with crops, but how this integration affects soils and crop yields is unclear. We studied the impact of cattle grazing an oat (Avena sativa L.) CC in the fall on soil properties of a silt loam in a field-scale irrigated no-till corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] experiment in eastern Nebraska. Each rotation was present each year in two adjacent fields. During the 5-yr study, Field I was grazed two times, and Field II was grazed three times. Grazing occurred on each field every other year. Treatments were arranged in a split-plot design with corn harvest (corn silage and high-moisture corn [HMC]) as main plots with no CC, nongrazed CC, and grazed CC as split plots. Corn silage was harvested 15 d before HMC; HMC was harvested about 25 d before typical corn harvest time. Cover crop grazing reduced aboveground CC biomass without affecting soil penetration resistance, bulk density, aggregate stability, hydraulic properties, organic matter concentration, particulate organic matter concentration, microbial biomass, and corn and soybean yields compared with nongrazed CC. Likewise, compared with no CC, nongrazed CC had no effect except for some improvement in soil microbial properties. However, corn silage harvest negatively affected most near-surface soil properties but not crop yields compared with HMC. Cover crop did not generally offset the negative impacts of corn silage on soil properties. In conclusion, CC grazing had no impact on soil properties and yields, but corn silage adversely affected soil properties.