Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: December 6, 1999
Publication Date: N/A
Technical Abstract: Perennial crops use water and nutrients over a longer period of time during the growing season than do annual crops. The objective of this study was to explore whether perennial crop species can attenuate nitrate losses in agricultural areas where nitrate contamination of groundwater is a concern. A comparison of various combinations of three perennial forages, one annual lcrop, two soil types, three precipitation regimes, and two states was accomplished using the computer model GLEAMS (Groundwater Loading Effects of Agricultural Management Systems). Model output was combined with spatial and attribute data in ArcView-GIS to produce coverages showing areas of concern in two states representing different climate zones - Nebraska and Illinois. Nitrate leaching was negligible in years with below normal mean annual precipitation, regardless of crop species or soil texture. The greatest losses occurred in normal and above-average mean annual precipitation regimes under an annual crop (corn) grown in Illinois on coarse-textured soils (56 kg/ha). Moderate losses (35 kg/ha) occurred under one perennial crop (alfalfa) but only on highly permeable (coarse-textured) soils in a humid climate (Illinois).