Calibration and Validation of the Ibsnat/Ceres Rice Model

Abstract

Two rice varieties were subjected to two nitrogen rates and three temperature regimes in the greenhouse and growth chambers to study the effects of temperature, variety and N fertilization on N uptake, development and growth of rice. Nitrogen fertilization had a significant effect on grain and straw yields for both varieties. High nitrogen application resulted in high grain yield and N stress reduced biomass production but had no effect on the timing of phonological events of variety Starbonnet, but delayed panicle initiation in variety K-C-A. Temperature affected grain yield and nitrogen uptake during the grain filling stage. High day and night temperature hastened maturation and resulted in lower filled grain percentage, lower 1,000-grain weight and lower overall grain yield. Nitrogen concentration and N uptake were higher in the higher temperature. However, the persistence of green color and a low ratio of grain N to straw N indicate that nitrogen translocation from straw to grain was diminished by the high temperature. The IBSNAT/CERES Rice Model was calibrated and validated with data collected from field experiments under a wide range of agroenvironments. The model was able to adequately predict phenological development for a wide range of agroenvironments. Model prediction of final biomass was also acceptable. The model is sensitive to seasonal variation and altitudinal difference and is able to mimic the high sensitivity of rice to temperature and solar radiation.