Abstract: With hybrid rice cultivar Liangyou Peijiu as test material, this paper studied its biological characteristics and water use efficiency under effects of four irrigation modes. Compared with continuous flooding irrigation, intermittent irrigation increased the leaf area index, photosynthetic rate and water use efficiency, and decreased the leaf transpiration rate. Semi-dry cultivation increased the leaf water use efficiency, while dry cultivation decreased the leaf area index, photosynthetic rate, and water use efficiency, and induced the leaf senescence in later growth period. Under intermittent irrigation, semi-dry cultivation and dry cultivation, the water consumption of paddy rice was 8.75%, 17.96% and 29.69% lower, and its grain yield was 24.02% higher but 5.07% and 38.93% lower than that under continuous flooding irrigation, respectively. The water use efficiency was the highest under intermittent irrigation, relatively high under semi-dry cultivation, but relatively low under continuous flooding irrigation and dry cultivation. Compared with other irrigation modes, intermittent irrigation increased the milled rice rate, head rice rate and grain length, while decreased the chalky rice and chalkiness. With the reduction of water consumption, the amylose content of rice grain decreased, but the gel consistency and protein content increased. Intermittent irrigation could be a favorable irrigation mode for the paddy rice planting in Southern China.

Key words: Vetiveria zizanioides, Cyperus alternifolius, Constructed wetlands, Hoggery, Wastewater treatment