Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: May 23, 2003
Publication Date: May 23, 2003
Citation: Hatfield, J.L., Prueger, J.H. Water quality implications of crop water use patterns. American Water Resources Assoc., Kansas City, MO. CD-ROM. Meeting Abstract.
Water quality impacts through either surface runoff or ground water recharge are closely linked with the seasonal water balance. This assumption is often made but there is little direct evidence to determine the seasonal magnitude of this effect. Studies on crop water use patterns throughout production fields have been conducted since 1991 in the Walnut Creek watershed near Ames, Iowa. The hydrology of Walnut Creek watershed is extensively subsurface drained and we have been monitoring the drainage flow at several scales, e.g., fields, subbasins, and the whole watershed since 1990. These studies have assembled a year-round data base for different soils and production systems that allows us to examine the potential effect of changing crop management on potential water movement. Soils with low organic matter recharge earlier in the spring than soils with higher organic matter contents and begin to drain first. The implication for these soils is a potential early spring movement of nitrate because these soils also show the lowest nitrogen use efficiency and have a larger pool of nitrogen available for leaching than the higher organic matter soils. Understanding the water balance at the watershed scale and the interactions with crop management will improve water quality when best management practices are adopted that consider the seasonal water balance.