M. Uma Devi

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 continuoussubmergence (CS) irrigation. However, the reported effect on yield varies widely and detailedcharacterizations of the hydrological conditions of AWD experiments are often lacking so thatgeneralizations are difficult to make. We compared the effects of AWD and CS on crop andwater productivity in rice in the field experimentations in India. The experiment was conductedin irrigated lowlands and followed AWD practices by using field water tube. Crop and waterproductivity was significantly differed between AWD and CS of irrigation. The average grainyield was 5.8–7.4 t ha-1 with AWD irrigation methods and 7.5–7.6 t ha-1 with CS. The pooledvalues of irrigation water applied, effective rainfall and seasonal volume of water input variedfrom 1390, 216 and 1646 mm, respectively under CS and 708 to 1142 mm, 238 to 300 mm and1048 to 1420 mm, respectively under AWD irrigation regimes. Irrigation water applied in AWDirrigation regimes amounted to 50.9 to 82.1% of CS (1390 mm), averaged over two seasons, thecrop 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 productivitythe AWD method of water management is the best practice to meet the cope of water scarcity inlowland rice production.