Consumptive use, water use efficiency and moisture extraction pattern of sapota (Achras sapota L.) as influenced by varying levels of irrigation and fertilizers

An experiment was conducted at Gujarat Agricultural University, Navsari during 1982–83 and 1983–84 with three moisture regimes based on IW/CPE ratios viz. 0.25.0.50 and 0.75 alongwith control and three levels of fertility viz. 500 9 N + 250 9P20 S + 250 9 K₂O 1000 9 N + 500g P₂O₅ + 500g K₂O and 1500g N + 750g P₂O₅ + 750 g K₂O/tree in factorial randomised block design with three replications. The results revealed that scheduling irrigation at an IW/CPE ratio of 0.50 (11 irrigations each of 80 mm depth to be applied at 32 days interval in winter and 18 days interval in summer) and fertilizing the crop with 1000 g N + 500 g P₂O₅ + 500 g K₂O/tree proved to be optimal for the sapota trees raised on clayey soils of South Gujarat. It gave maximum fruit yields with a water use efficiency of 0.81 kg/tree/mm of water applied. The observed consumptive use of water by sapota was 2007 mm which proved optimum. The moisture extraction decreased with the increase in depth, irrespective of irrigation and fertilizer treatments. About 66 per cent moisture was extracted from first half of root zone (0.75 cm) where as 34 per cent from second half of root zone (75–150 cm).