Modeling Nitrate Movement and Dissipation in Fertilized Soils1
- K. E. Saxton,
- G. E. Schuman and
- R. E. Burwell2
It is important to know the fate of nitrogen (N) fertilizers to ensure crop production and avoid pollution, but frequent measurement of soil N is difficult. Therefore, we developed a digital model to calculate the occurrence, movement, and dissipation of nitrate-nitrogen (NO3-N) within the soil profile of fertilized agricultural lands. Daily NO3-N amounts and distributions within a 1.8-m soil profile were calculated by representing the major processes influencing NO3-N for the entire year. Daily soil moisture amounts and movement were predicted by a previously developed soil moisture-evapotranspiration model.
Profiles of NO3-N measured periodically on two research watersheds in western Iowa, one normally fertilized (168 kg/ha per year) and the other excessively fertilized (448 kg/ha per year) with N were used for model verification. The daily calculations for the fertilized cornfields (Zea mays L.) with moderately permeable soils included NO3-N movement, dissipation, and profile leaching. The predicted NO3-N profiles closely represented those measured.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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