Grain Yield and Water Use Efficiency of Riceberry Rice in Response to Water-Saving Irrigation Techniques

Abstract

Reducing irrigation water in rice fields while maintaining high grain yield is important for the sustainable rice production. However, water-saving techniques has not been widely adopted by Thai farmers because of constrains in effectiveness and reliability. About 10-20 years ago, the alternate wetting and drying (AWD) technology has been developed and recommended to irrigated rice farmers in Asian countries. But the performance of the AWD technology has not yet been evaluated for water use efficiency for Riceberry rice. The objective of this study was to determine the effects of two AWD treatments (AWD1, AWD2) had on growth grain yield and yield components of Riceberry rice as compared to the conventional farmer’s practice by continuous flooding method (CF). In AWD1, water level was let to drop to -5 cm below ground level, the field was then reflooded until the water level reached 5 cm above ground; in AWD2, water level was maintained at 5 cm above ground from the first day of transplanting until 25 and 45 days after transplanting when water level was let to drop to -15 cm below the ground level and then reflooded the field until the water level reached 5 cm above ground. While in continuous flooding method (CF) the water level was kept at 5 cm above ground for the entire season. The experiments were carried out in the irrigated paddy fields in Chiang Mai provinces in dry seasons of 2016 and 2017. Results revealed that both AWD1 and AWD2 consumed less water than the continuous water supply method, (CF) at approximately 31.75 – 34.06 % in 2016 and about 33.38 – 40.59 % in 2017 with no different in grain yield and ield components. Moreover, both the irrigation water productivity and water use efficiency of AWD method were higher than those of the CF method. In conclusion, the AWD water-saving irrigation techniques are the appropriate water management techniques for cultivation of Riceberry rice and it is an effective way to reduce the amount of water used in the agricultural sector in Thailand.