EFFECTS OF AGRICULTURAL NUTRIENT MANAGEMENT ON NITROGEN FATE AND TRANSPORT IN LANCASTER COUNTY PENNSYLVANIA¹

Abstract

Nitrogen inputs to, and outputs from, a 55‐acre site in Lancaster County, Pennsylvania, were estimated to determine the pathways and relative magnitude of loads of nitrogen entering and leaving the site, and to compare the loads of nitrogen before and after the implementation of nutrient management. Inputs of nitrogen to the site were manure fertilizer, commercial fertilizer, nitrogen in precipitation, and nitrogen in ground‐water inflow; and these sources averaged 93, 4, 2, and 1 percent of average annual nitrogen additions, respectively. Outputs of nitrogen from the site were nitrogen in harvested crops, loads of nitrogen in surface runoff, volatilization of nitrogen, and loads of nitrogen in ground‐water discharge, which averaged 37, less than 1, 25, and 38 percent of average annual nitrogen removals from the site, respectively. Virtually all of the nitrogen leaving the site that was not removed in harvested crops or by volatilization was discharged in the ground water. Applications of manure and fertilizer nitrogen to 47.5 acres of cropped fields decreased about 33 percent, from an average of 22,700 pounds per year (480 pounds per acre per year) before nutrient management to 15,175 pounds of nitrogen per year (320 pounds per acre per year) after the implementation of nutrient management practices. Nitrogen loads in ground‐water discharged from the site decreased about 30 percent, from an average of 292 pounds of nitrogen per million gallons of ground water before nutrient management to an average of 203 pounds of nitrogen per million gallons as a result of the decreased manure and commercial fertilizer applications. Reductions in manure and commercial fertilizer applications caused a reduction of approximately 11,000 pounds (3,760 pounds per year; 70 pounds per acre per year) in the load of nitrogen discharged in ground water from the 55‐acre site during the three‐year period 1987–1990.

Comparison of local- to regional-scale estimates of ground-water recharge in Minnesota, USA

“…Specific yield (Sy) for the WTF method was estimated using a water-budget approach (Walton, 1970;Hall and Risser, 1993;Healy and Cook, 2002). For late fall through early spring, rates of ET in Minnesota are small, and soil-moisture contents are usually at their greatest level.…”

Hydrogeologic setting and simulation of pesticide fate and transport in the unsaturated zone of a regolith-mantled, carbonate-rock terrain near Newville, Pennsylvania

“…The simulated recharge rate was appreciably higher than the 41 percent of annual precipitation estimated for the carbonate-rock terrain of the Conodoguinet Creek Basin for a 5-year period (Becher and Root, 1981). However, the simulated recharge rate was nearly identical to the 53 percent of annual precipitation estimated at an agricultural field site in a carbonate terrain of Lancaster County for a 6-year period (Hall and Risser, 1993).…”

Improving AVSWAT Stream Flow Simulation by Incorporating Groundwater Recharge Prediction in the Upstream Lesti Watershed, East Java, Indonesia

“…Due to the availability of water level data and the simplicity of estimating recharge rates from temporal fluctuations or spatial patterns of water levels, the groundwater recharge can be calculated as follows (Hall and Risser 1993;Healy and Cook 2002;Scanlon et al 2002).…”