The Impact of Fertilizer Use and Crop Management on Nitrogen Content of Subsurface Water Draining from Upland Agricultural Watersheds

Abstract

AbstractSpring flow and stream base flow sites were sampled weekly on and adjacent to a 123‐ha agricultural watershed in the Allegheny‐Cumberland Plateau physiographic region of east‐central Ohio. Nitrogen content of samples was used to determine the influence of various N fertilizer and crop management practices on the quality of subsurface water draining from defined contributing areas.Measured nitrogen contents of spring flow were related to fertilizer N regime of the different agricultural practices investigated. Changes in land management on the area contributing to spring flow were reflected in changes in nitrogen content of water from that spring. The amount of nitrogen which was transported into the stream channel was directly related to seasonal variation in subsurface flow rate in two ways. First, the concentration of N in spring flow increased with an increase in the amount of water percolating through the overlying soil and shale. Second, the extent to which downstream quality was affected, i.e., the distance from the area of fertilizer application at which an increase in nitrogen content could be detected, also increased with the volume of flow from the springs.