The Effects of Different Combinations of Irrigation and Planting Method on Yield and Water Use Efficiency of Rice in Jianghuai Region

【Objective】 Yield and water use difference of crop depend on many agronomic practices and environmental constraints. Taking rice as an example, this paper elucidates how planting pattern and irrigation combine to affect water use efficiency and yield in the region of Jianghuai in southeast China. 【Method】 The experiment was conducted from 2018 to 2019 in a field. It consisted of four treatments: traditional flooding irrigation +puddled transplant (FI+PTR), traditional flooding irrigation+direct drill (FI+DSR), intermittent irrigation+puddled transplant (II+PTR), intermittent irrigation+direct drill (II+DSR). In each treatment, we measured yield components, water consumption and water use efficiency of the rice. 【Result】 Compared with flooding irrigation, intermittent irrigation did not resulted in significant change in rice yield, but reduced the evapotranspiration (ET) by 8.16%~9.84%, and increased water productivity by 10.68%~14.73%, depending on planting methods. Compared with PTR, DSR reduced rice yield by 5.33%~10.46% and water productivity by 12.36%~23.14%, while increasing ET by 7.32%~8.00%. Compared with PTR, DSR increased the effective panicle numbers, while reducing the number of grains per panicle, 1 000-grain weight, and seed setting rate, all at significant levels. Compared with II+PTR, II+DSR reduced rice yield by 5.99%~12.59% and water productivity by 12.55%~24.79%, while increasing ET by 7.21%~7.63%. The increased ET in the direct drill treatment was mainly due to its increase at the seedling stage, after which there was no significant difference in ET between the treatments. 【Conclusion】 Intermittent irrigation + transplant is optimal for rice production in the studied region; it not only increased grain yield and water productivity but also reduced evapotranspiration.