Spectral Observations for Estimating the Yield and quality of Rice, and studies on optimal amount of fertilizer at ear forming stage of rice.

摘要

[ABSTRACT] We already cleared that it is possible to estimate yield of rice from NDVI at heading time. NDVI is expected to be important factor for manuring practice (i.e. topdressing at ear forming stage). In this study, the spectral technique using a handheld Multispectral Radiometer was examined to estimate yield and quality of rice. We found that it was possible to estimate the yield of rice from NDVI at a ear forming stage, the amount of topdressing at ear forming stage, daily mean temperature and daily amount of precipitation from a ear forming stage to a harvest time. We also observed that it was possible to assume the nitrogen concentration of brown rice by estimating the amount of nitrogen absorbed to unhulled rice by the technique as in yield. For the future, it will become possible to determine the optimal amount of topdressing at ear forming stage by further research of weather factors.