Standardization of alternate wetting and drying (AWD) method of water management in low land rice (Oryza sativa (L.))

Alternate wettting and drying (AWD) systems save water compared with continuous submergence (CS) irrigation. However, the reported effect on yield varies widely and detailed characterizations of the hydrological conditions of AWD experiments are often lacking so that generalizations are difficult to make. We compared the effects of AWD and CS on crop and water productivity in rice in the field experimentations in India. The experiment was conducted in irrigated lowlands and followed AWD practices by using field water tube. Crop and water productivity was significantly differed between AWD and CS of irrigation. The average grain yield was 5.8–7.4 t ha−1 with AWD irrigation methods and 7.5–7.6 t ha−1 with CS. The pooled values of irrigation water applied, effective rainfall and seasonal volume of water input varied from 1390, 216 and 1646 mm, respectively under CS and 708 to 1142 mm, 238 to 300 mm and 1048 to 1420 mm, respectively under AWD irrigation regimes. Irrigation water applied in AWD irrigation regimes amounted to 50.9 to 82.1% of CS (1390 mm), averaged over two seasons, the crop in different AWD irrigation regimes used water 63.6 to 86.2% of the CS (1646 mm) suggesting that the AWD practice enabled water saving of 13.8 to 36.4% in different treatments. Therefore, in view of considerable water saving (26.6 to 35.0%) and higher water productivity the AWD method of water management is the best practice to meet the cope of water scarcity in lowland rice production.