Determination of actual evapotranspiration for summer clusterbean (Cyamopsis tetragonoloba) using mini-lysimeters in hot arid zone of India

A field experiment was conducted for three consecutive years 2015-17 during the summer season at the experiment farm of ICAR Central Arid Zone Research Institute, Jodhpur to determine the actual evapotranspiration of clusterbean [Cyamopsis tetragonoloba (L.) Taub.] using mini-lysimeter by imposing different levels of irrigation based on cumulative pan evaporation (CPE) 50 mm irrigation at 100, 80, 60 and 40% of CPE. Three year averaged actual crop ET was observed 686, 554, 454 and 340 mm under 100, 80, 60 and 40 % irrigation levels, respectively. The highest crop ET was recorded under 100% followed by 80, 60 and 40% irrigation levels. However, maximum water productivity (0.35 kg m^-3) at 80% irrigation level, while the lowest (0.21 kg m^-3) was observed at 40% irrigation level.The results also indicated that to achieve maximum water productivity, crop ET would need to be at least 554 mm and the crop can save 19.2% (132 mm) of water with a compromise in yield reduction by 10.4% (225 kg).