The Lowest Optimal Irrigation Bound on the Different Key Water Requirement Period of Rice

This paper studies on the influence of the irrigation schedule,leakage and yield of the jointing-booting stage and the full heading stage under the condition of continuous irrigation with 70 to 90 percent saturated soil moisture content in the 5 m2 test-pits.The results showed that the irrigation times,modulus and quota changed in the different irrigation conditions.The irrigation times were from 28 to 30,the irrigation quota was 8 190 to 9 450 m3/hm2,during rice growth period.The leakage of different treatment decreased with the irrigation quantity decreasing.The leakage was from 54.22 to 64.25 percent of the irrigation quality.The irrigation requirement of the jointing-booting stage was more sensitive than the full heading stage.The jointing-booting stage should keep wetness state and the lowest optimal irrigation bound of the full heading stage was 90 percent.