A systems approach to evaluate nutrient and pesticide transport from artificially drained cropland

Abstract

Artificial drainage by subsurface and open drains, which is practiced in heavily cultivated areas of the United States, can enhance the transport of nutrients and pesticides to surface waters. Analyses of drainage data show that Ohio, Iowa, Indiana, Illinois, Michigan, and Minnesota are the leading states with artificially drained croplands. Several experimental fields in different parts of the country utilizing artificial drainage have been monitored in the past to determine the loss of nutrients and the results of 12 such studies are summarized here in tabular form. The several interacting processes that take place in a watershed and that contribute to the movement of nutrients and pesticides to surface waters are extremely complex. To effectively study the dynamic nature of the transport processes and to develop control measures, an interdisciplinary systems approach is proposed. The central feature of the systems approach is the development of a computer simulation model representing the time-variant interaction of the major biophysiochemical processes that contribute to the loss of nutrients and pesticides. A flow diagram showing the inputs, outputs, and interactions of the various processes considered in the model, along with a description of the field monitoring program designed to provide the data for the model development, is given in the report.