Relationship Between Canopy Temperature at Flowering Stage and Soil Water Content, Yield Components in Rice

The canopy temperature of rice at the flowering stage and the soil water content were investigated under different soil water treatments (the soil water contents were 24%, 55%, 90% and 175% at the flowering stage). The canopy temperature was lower than air temperature, and the soil water content significantly influenced the canopy temperature. The lower the soil water content, the higher the canopy temperature, the less the accumulative absolute value of canopy-air temperature difference. Moreover, the maximum difference between treatments and CK in the accumulative absolute value of canopy-air temperature difference appeared at 13:00 p.m. in a day, thus, it could be considered as a suitable measuring time. Under the lowest water content treatment, the peak flowering occurred in the first three days (about 70% of panicles flowered), resulting in shortened and lightened panicle of rice. As to the CK and the high water content treatments, the peak flowering appeared in the middle of flowering duration, with longer panicle length and higher panicle weight. Results indicated the lower the soil water content, the less the filled grain number and grain yield.