Optimizing soil moisture regime to increase water use efficiency of sugarcane (Saccharum spp. hybrid complex) in subtropical India

Field studies were conducted for 2 years in alluvial soils of north India to determine water use, water use efficiency and yield of sugarcane on a sandy loam and a silty clay loam soil under various moisture regimes. Irrigation scheduling was based on the ratio between irrigation water and cumulative pan evaporation (IW/CPE). Deep irrigations at 80 mm were applied at IW/CPE ratios of 0.25, 0.50, 0.75, 1.00 and 1.25. Total water use was higher in the plant crop than the ratoon crop under all IW/CPE ratios. Mean water use efficiency (WUE) of plant cane (71 kg/ha/mm) was also higher compared to ratoon cane (63 kg/ha/mm). On the heavier silty clay loam soil, losses through deep percolation ranged from 25 to 30% in the first crop and 7–13% in the second crop season. Maximum effective rainfall was recorded in the driest soil moisture regime. Mean cane yield on the sandy loam soil increased significantly up to 1.0 IW/CPE ratio. We conclude that in subtropical India, irrigation of sugarcane during the tillering period should be applied at 0.75 and 1.00 IW/CPE ratios in silty clay loam and sandy loam soils, respectively.