Effect of different sensor-based irrigation levels on growth, yield and economic viability of spinach (Spinacia oleracea L.) under reduced runoff farming

Sensor based irrigation scheduling plays a vital role to rationalize irrigation water. A field experiment was conducted at AICRP on Dryland Agriculture, UAS, GKVK, Bengaluru during 2021-22 and 2022-23 to study the effect of irrigation scheduling in spinach Irrigation was assessed at 75, 50 and 25% ASM along with surface irrigation as a control. Scheduling irrigation at 75% ASM resulted in significantly higher growth attributes viz., plant height (36.18 and 37.83 cm, respectively), number of leaves (22.61 and 22.19, respectively), leaf length (34.17, 35.23 cm, respectively) leaf width (11.10 and 10.29 cm, respectively), fresh weight (55.95 and 63.38 g plant^-1) and dry weight (6.20 and 5.06 g plant^-1) at 30 and 60 DAS, respectively. Furthermore, scheduling irrigation at 75% ASM resulted in the higher mean leaf yield (3.85 t ha^-1) compared to surface irrigation (2.89 t ha^-1). Water use compared to surface irrigation decreased by 60.00 and 57.18 per cent at 75% ASM, 51.90 and 50.92 per cent at 50% ASM and 46.00 and 48.00 per cent at 25% ASM during 2021 and 2022, respectively. WUE followed a descending order: 75% ASM (3.15 kg m^-3) > 50% ASM (2.28 kg m^-3) > 25% ASM (1.06 kg m^-3) > surface irrigation (0.96 kg m^-3). The gross return (Rs. 456966 ha^-1), net return (Rs. 223736 ha^-1) and B: C ratio (1.96) recorded substantially higher at 75% ASM over surface irrigation.