Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: February 5, 1999
Publication Date: N/A
Technical Abstract: U.S. EPA federal guidelines for clean drinking water mandate that potable water contain a maximum of 10 PPM nitrate. Leaching of NO3-N from agricultural lands overlying sensitive aquifers (thin, permeable soils and shallow water tables) poses health risks when aquifers are contaminated and nitrate levels increase above 10 PPM. By combining computer simulation models with GIS technology, the long-term potential mass of leachable NO3- can be determined, and areas of greatest concern identified and delineated. Current BMPs in these sensitive areas can be evaluated using models that predict their impacts on nitrate losses to groundwater. New recommendations concerning crop selection and BMPs can then be explored through modeling that would minimize nitrate leaching potentials. Research suggests that perennial plant species use water and nitrogen over a longer period and in greater amounts than annual crops. Recent studies in SW Minnesota indicate that 20-50 Lb. N/acre/yr from nitrogen inputs could be trimmed from curren agricultural systems without yield reductions. This study compares and contrasts various combinations of perennial and annual crops, soil types, climates, and management practices using the computer model GLEAMS (Groundwater Loading Effects from Agricultural Management Systems) to develop improved BMPs for agricultural lands overlying sensitive aquifers. Modeling analyses using this approach can be completed in a matter of weeks, whereas field-plot experiments would require several years and considerable resources. By using computer simulation models and GIS to first identify areas of concern, then develop maps and appropriate management systems for these areas, sensitive aquifers can be protected from further or future nitrate contamination.