Monitoring of rice plant growth in Northeast China using dual-wavebands crop growth analyzer

In order to realize precision management on rice crop, field experiments and analyses on crop growth monitoring in rice fields were conducted with a prototype dual-wavebands crop growth analyzer developed before. The incident sunlight and reflective light from crop canopy were measured at the wavebands of 610 and 1220 nm respectively, and then the canopy reflectance and some vegetative indices were calculated. The nitrogen stress experiments were conducted in the two experimental paddy fields in northeast China at the tillering and heading stages of rice plant. Results showed that the leaf nitrogen concentration and dry biomass had good correlations with both RVI and NDVI, and had higher correlations with NDVI than with RVI. During the tillering stage, the average NDVI had a significant correlation with fertilizer amount (R2=0.94) and the nonlinear relationship indicated over-fertilization could decrease NDVI. The average NDVI at both the tillering and heading stages were significantly correlated with the average yield, and the R2 at heading stage reached to 0.96. The study showed this analyzer has great potential in controlling income, increasing yield and providing theory and technology support for rice variable management.