Intercropping maize and Caucasian clover to reduce environmental impact of maize silage production

摘要

Maize {Zea mays L.) silage has become an increasingly important forage crop in high output dairy farming systems in Europe and North America because of its high energy density, relatively uniform nutritive value, and efficiency of production. But due tolack of surface residue and organic matter inputs and high nitrogen (N) fertilizer inputs, maize silage production is one of the most demanding cropping systems imposed on our soil and water resources. We investigated intercropping maize with the persistent rhizomatous legume, Caucasian clover (Trifolium ambiguum M. Bieb.), as a means to provide continuous living groundcover to minimize nitrate leaching, nutrient runoff and soil erosion. Maize was sown into existing stands of Caucasian clover that had been suppressed to reduce competition, and into areas with no clover. Total nitrate-N leached was reduced by 74% relative to the control monocrop maize under intercropped maize silage. On loess soils with 8 to 15% slope, during simulated, short, heavy rainstorms, Caucasian clover intercrop reduced water runoff by 50%, soil loss by 77%, and P and N losses by 80% relative to monocrop maize. Intercropping maize with Caucasian clover can eliminate N-fertilizer inputs and greatly reduce negative environmental impacts associated with maize silage production.