PREDICTION OF AMMONIUM NITROGEN FERTILIZER DISAPPEARANCE FROM SOILS IN THE PRESENCE AND ABSENCE OF N‐SERVE(R) NITROGEN STABILIZERS

Estimation of the loss rate of ammonium nitrogen from soil (nitrification) and the effect nitrapyrin has on this biological process are made possible by the development of a computer-based system simulation. Inputs to the model are: site location, soil pH, ammonium nitrogen and nitrapyrin application rates and dates, and percentage of soil organic matter. Outputs are: day of the year and nitrapyrin and ammonium nitrogen remaining in the soil. Rates of nitrification and disappearance of nitrapyrin are influenced strongly by soil temperature. Therefore, a soil-temperature-prediction function is part of the model, and the predicted temperature is, in large part, the independent variable that runs the simulation model.