Impact of Water Management on Rice Varieties, Yield, and Water Productivity under the System of Rice Intensification in Southern Taiwan

The system of rice intensification (SRI) uses less water and enhances rice yield through synergy among several agronomic management practices. This claim was investigated to determine the effects of crop growth, yield and irrigation water use, using two thirds of the recommended SRI practices and two rice varieties, namely Tainan11 (TN11) and Tidung30 (TD30). Irrigation regimes were (a) intermittent irrigation with three-day intervals (TD303 and TN113); (b) intermittent irrigation with seven-day intervals (TD307 and TN117) and (c) continuous flooding (TD30F and TN11F). Results showed that intermittent irrigation of three- and seven-day intervals produced water savings of 55% and 74% compared with continuous flooding. Total water productivity was greater with intermittent irrigation at seven-day intervals producing 0.35 kg·grain/m3 (TN117) and 0.46 kg·grain/m3 (TD307). Average daily headed panicle reduced by 166% and 196% for TN113 and TN117 compared with TN11F, with similar reduction recorded for TD303 (150%) and TD307 (156%) compared with TD30F. Grain yield of TD30 was comparable among irrigation regimes; however, it reduced by 30.29% in TN117 compared to TN11F. Plant height and leaf area were greater in plants exposed to intermittent irrigation of three-day intervals