Accuracy of estimated amount of nitrogen release from coated ureas by using AMeDAS mesh data in paddy rice culture

Abstract

We estimated the release of nitrogen from coated urea in rice cultivation, using soil temperature estimated from AMeDAS (Automated Meteorological Data Acquisition System) 1-km-grid data (temperature and sunshine duration). The RMSE of soil temperature estimated at 9 points in Okayama prefecture was 0.89 ℃. Soil temperatures were easily estimated by multiple regression of data observed at 3 points to interpolate data at target sites. The estimated release of nitrogen fit measured values well, with an average difference of approximately 5% and an estimated error of the date of initial release of about 2 days. These results indicate that the release of nitrogen from coated urea can be estimated simply from AMeDAS 1-km-grid data.