Sediment and Nutrient Loss in Reduced Tillage Systems.

Sediment and nutrient loss in runoff from agricultural fields are an environmental concern. Tillage and residue cover are important factors that affect these losses. No-tillage has been promoted to reduce these losses. The objective of this study is to compare sediment (TS) and nutrient losses from runoff in no-tillage (NT) with those in chisel/disked (CD) systems.

This study was designed to be representative of Pennsylvania's dairy-based agricultural systems which commonly grow corn for silage and fertilize with manure in the spring to meet the crop's nitrogen requirement. Two fields were chosen – one that was well-drained (WD) and another which was moderately well-drained (MWD). Each field was divided into 4 plots (replications) for each tillage method. Rain simulations were performed after planting, at full canopy closure, and after harvest. The plots were pre-soaked with 3 cm of rain water 24-hours in advance and then rained on at a rate of 6 cm hr^-1 for 1 hour at the beginning, middle, and end of the corn growing season. Runoff was collected and weighed in tota, and analyzed for TS, and several species of nitrogen (N) and phosphorus (P).

In 2007, NT resulted in 75% reduction in TS losses throughout the season on both sites. At planting, NT had substantially higher losses in all forms of P and N on both sites due to lack of incorporation of the manure. However, at half and full corn canopy closure, the CD plots had substantially higher losses of particulate P, total, P, and total dissolved N.