Abstracts of Nippon Dojo-Hiryogaku Zasshi 93 - 5

Corn silage was grown yearly from 2007 to 2012 with three different fertilization treatments: one experimental plot was treated with chemical fertilizer (C) and the other two plots with organic fertilizers of composted cow manure (M) and slurry (S), respectively. A monolith-type capillary lysimeter packed with an undisturbed subsurface soil core of 20–70-cm depth and a diameter of 25 cm was buried below the plow layer in the field to measure leachate volume and inorganic N concentration. The simulated results using modified LEACHM showed a reasonably good agreement with the measured inorganic N concentration patterns, such as the magnitude and timing of peak N concentrations, in the three treatments despite the dif-ferences in the applied N sources. However, the performance of the model with respect to cumulative amounts of inorganic N leached yearly and/or during the whole experimental period varied between years and plots. Overall, the model was a valuable tool for predicting N leaching and examining various scenarios in corn silage fields treated with different N sources in this region. Future studies on separately determining the N mineralization rates of humus and crop residue, as well as the N transformation of composted manure and slurry, would be valuable in further improving the model’s prediction.