Tillage Studies with a Corn-Soybean Rotation: Surface Runoff Chemistry
- L. B. Owens and
- W. M. Edwards
When soybean [Glycine max (L.) Merr.] is grown on sloping soils, there is a high potential for soil and nutrient losses. The purpose of this study was to compare nutrient losses in surface runoff across a range of watershed conditions when tillage practice was a variable. For 6 yr in east-central Ohio, nutrient concentrations and transport in surface runoff were measured from six small (<1-ha) watersheds planted to a corn (Zea mays L.)-soybean rotation. Two watersheds were chisel plowed each year, two were paraplowed, and two received no-tillage. Rye (Secale cereale L.) provided winter cover following soybean harvest. Nitrate-N and K concentrations in surface runoff were greater during corn years than soybean years, but there was no significant difference among tillage treatments. There were no consistent differences between crops or among tillage practices for the transport of soluble P, soluble K, and total organic C (TOC). Most of the NO3-N loss was in the runoff from a small percentage of runoff events. Although NO3-N concentrations in surface runoff frequently exceeded 10 mg/L during the corn years, the actual amount of N lost was small. But because of year-to-year variation in runoff, which masked most of the differences resulting from cropping or tillage practice, there is a need for long-term research (>6 yr) to assess the environmental risks associated with a particular management practice.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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