Water and Radiation Use Efficiency of JaponicaRice with Different Irrigation Methods in Semi-humid Area of China

Limited freshwater resources restricted the yield of rice in the semi-humid area of Heilongjiang Province, China. To identify suitable irrigation methods for rice, the irrigation experiment was carried out at Qing’an Irrigation Experimental Center in 2018. The aim was to determine impacts between different irrigation methods and intercepted photosynthetically active radiation, aboveground dry matter, radiation use efficiency and water use efficiency. The comparison of rice irrigation methods showed that control irrigation was an optimal irrigation method. Control irrigation can get maximum water use efficiency and maximum radiation use efficiency in the semi-humid area of Heilongjiang Province. Results showed that control irrigation could be used to increase both water use efficiency and radiation use efficiency compared with wet irrigation and flood irrigation. Results also confirmed that control irrigation intercepted the most photosynthetically active radiation and accumulated the most aboveground dry matter under three irrigation methods. Our results demonstrated that control irrigation produced higher radiation use efficiency and water use efficiency with less irrigation water.