Nitrogen Management Influences on N Losses to Tile and Surface Water

Nitrogen (N) is a naturally occurring element that is essential to plant growth and crop production. Agriculture has been identified frequently as a major contributor of nitrate-nitrogen to surface water throughout the developed world. Omernik (1977) reported that total N concentrations were nearly nine times greater downstream from agricultural lands than downstream from forested areas with the highest concentrations being found in the Corn Belt States of the Upper Mississippi Basin. Nitrate-N is continually supplied to streams and rivers through mineralization of soil organic matter, particularly where tile drainage has exposed formerly wet soils to oxidation and through the application of fertilizer and animal manures to crop land

Fall vs Spring Application of Nitrogen

Fall application of nitrogen (N) has been a way-of-life for many Upper Midwest farmers for a number of years. The primary advantages of fall compared to spring application are: (1) spread out the work load for both the farmer and dealer, (2) reduce potential soil compaction by eliminating another field operation in the spring, and (3) slight price advantages for fall application. But with the eight-month period between application and the time of greatest N uptake by com, the potential loss of N from the soil system increases. These potential losses lead to poorer economic return and contamination of surface and groundwaters via leaching out of the crop rooting zone

The University of Minnesota Supplemental Fertilizer Nitrogen Worksheet

The University of Minnesota Supplemental Fertilizer N Worksheet was developed as a simple, quick, reliable, and inexpensive alternative decision aid tool to assess potential fertilizer N losses. The worksheet is a series of three questions with multiple-choice answers. Depending on the answers, numbers are assigned for each question that are summed, and then the recommendation is made for supplemental N applications. It has been used with success for 10 years in Minnesota as a decision aid as well as an educational tool regarding fertilizer N management strategies

Nitrogen Management Related to Groundwater Quality in Minnesota

ABSTRACT-Minnesota ranks fifth in overall fertilizer nitrogen (FN) use. Nitrogen is essential for crop production; however, there are concerns about this use relative to profitability and potential impacts on groundwater. There are many sources and sinks of nitrogen in ecosystems. The impact of agricultural management practices on groundwater requires that all sources and fates be considered before FN rates are determined. Research is underway to evaluate relationships between FN application for continuous com and movement of nitrate through soil profiles. Growers making N management decisions have to be able to evaluate the complex nature of N in the environment when they determine their crop needs. Computer software is under development to provide this information on a site specific basis