Soil Erosion and Nutrient Runoff in Corn Silage Production with Kura Clover Living Mulch and Winter Rye

Corn (Zea mays L.) silage is a productive and popular forage crop that can exacerbate soil loss, surface water runoff, and nonpoint source nutrient pollution from agricultural fields. The objective of this research was to compare soil loss, nutrient runoff, and soil physical properties in conventional monocrop corn silage production to production in Kura clover (Trifolium ambiguum M. Bieb.) living mulch or with a winter rye (Secale cereale L.) cover crop. Five runoff events from simulated rainfall were conducted over a 1-yr period on loess soils with 8 to 15% slope. Based on weighted averages across all simulations, Kura clover living mulch reduced runoff by 50%, soil loss by 77%, and P and N losses by 80% relative to monocrop corn. Rye planted aft er corn silage harvest reduced runoff by 67%, soil loss by 81%, P loss by 94%, and N loss by 83%. When rye was planted following corn silage in Kura clover living mulch, runoff was reduced by 68%, soil loss by 77%, P loss by 94%, and N loss by 84% relative to monocrop corn. Greater groundcover in the Kura clover and rye treatments was the primary factor in reducing soil and nutrient losses, but soil aggregate stability and soil disturbance from rye planting were also associated with improved infiltration and reduced runnoff. When grown in Kura clover living mulch, both corn and rye had lower forage yields, a trade-off with the environmental benefits; but that economic loss would be partially off set by lower fertilizer requirements.