Mineralization of soil organic nitrogen and its movement in an andosol under field conditions: Model simulation and its verification
1990
Saito, M. (Tohoku National Agricultural Experiment Station, Morioka (Japan))
The present study was conducted to simulate the herbivore of nitrate in soil and verify simulation under field conditions. The mineralization of soil organic nitrogen was estimated from soil temperature, based on nitrogen mineralization parameters (NMP) for the zero order reaction model. Movement of nitrate through a soil profile was estimated based on both simulated water movement by a mathematical model and adsorption of nitrate with the soil. The parameters required for simulation were (1) NMP obtained by incubation of soils, (2) relationships between pF and moisture contents of soils, (3) unsaturated hydraulic conductivity estimated based on dairy changes in pF, precipitation and evaporation in the field, and (4) adsorption isotherms of nitrate with soil. Daily precipitation, evaporation and soil temperature were necessary for application of the simulation model. To verify the model, the following plots were set up in the experimental field of Tohoku National Agricultural Experiment Station: (1) unfertilized-uncropped plot, (2) fertilized-uncropped plot and (3) fertilized-cropped plot, in which corn (Zea mays L. cv. P3424) was grown. The soil was a Melanudands. Changes in pF, nitrate concentrations in soil solution and those in soil were examined during the experiment (from 23rd May to 1st September in 1987). Soil solution was collected by sucking through porous cups previously buried at various depths in the soil. Soils were collected with a whole auger
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