Common Ground Summit: Soil Mineralization Controversy

An important area is which there are often different perspectives among agronomists, biogeochemists, hydrologists, and ecologists is in determining the contribution of soil organic matter to nutrient loading. From a large regional (e.g. watershed) perspective the flux of dissolved nitrogen appears to be often strongly related to fertilizer applications, both spatially and historically. Yet, agronomists stress the importance of the mineralization of soil organic matter as a principal source of nitrogen loss to groundwater and surface water.

Contrast, for example, the hydrological approach of the SPARROW modeling with that an agronomic approach to assessing Agricultural Nitrogen Trends in the Mississippi Basin, which considers not only nitrogen sources but also mineralization of crop residues, crop senescence, and soil immobilization.

Although there are other differences of interpretation also involved, the raging debate among Illinois scientists about the contributions of fertilizers to water quality conditions in state waters and as a contribution to hypoxia in the Gulf of Mexico:

This is not just an academic debate because policy positions taken by the Governor of Illinois were based on Krug and Winstanley's interpretations that fertilizer use was not contributing to Gulf of Mexico hypoxia.

Last updated September 17, 2001