Abstract: Applying model to simulate the process of rice heat injury and its potential yield loss is a key part of the research on high temperature resistance of rice, but there exist some difficulties in measuring micrometeorology of rice canopy accurately. This study adopted MINCER, which is the latest newly development for rice canopy micrometeorological measurement, to determine the microclimate conditions in rice canopy during heat injury. Comparing the observation data with the meteorological data of the neighborhood national basic meteorological station, three groups of comparative data were sorted, such as date of rice canopy, date of upper rice field and date of open area. The date of upper rice field was detected at the height of 1.9 m, which is the twice plant height above the field, and the date of open area was observed at the height of 1.5 m. The experiment shows that the seed setting rate of tested cultivars was significantly reduced by 4% after sufferring high temperature weather at flowering stage. The daily average temperature of rice canopy, upper rice field and open area were increased in turn, and the temperature of rice canopy and upper rice field were 2.05℃ and 0.92℃ lower than the open area. But during continuous high temperature period, the rice canopy temperature showed an abnormal increase periodically. Contrary to the case of temperature, relative humidity of rice canopy, upper rice field and open area were decreased in sequence, relative humidity of rice canopy and upper rice field were 14.55% and 5.97%(absolute value) higher than open area. Under high temperature condition, the variation range of the difference between upper rice field and the rice canopy temperature was less than under normal weather, and great temperature difference between them appeared earlier than under normal weather condition. This was the same as the relative humidity. These results were of great significance to guide the research of the rice heat injury identification conditions and the simulation process of rice heat injury.

Key words: hybrid rice, high temperature, canopy, MINCER