Growth, Productivity, Economics, and Water Use Efficiency of Rabi Castor (Ricinus communis) as Influenced by Drip Fertigation

A field experiment was conducted in shallow Alfisols at Hyderabad for three consecutive years to evaluate the performance of castor on yield, water use efficiency, and economics for rabi castor cultivation under different irrigation schedules. The experiment was laid out in randomized block design and replicated thrice. The experiment comprised 100, 80, 60 percent of N and K applied through urea and K2SO4 through a drip in two schedules (0.6 and 0.8 Epan) compared with soil application of nutrients and flood irrigation. Significantly higher rabi castor seed yield (3,302 kg ha-1), oil yield (1479 kg ha-1), highest gross returns (1,25,489 ha-1), net returns (86,754 ha-1) and B:C ratio (3.65) were realized when irrigations were scheduled by drip at 0.8 Epan along with the supply of the full amount of N & K through fertigation. However, the highest water-use efficiency (4.85 kg ha-1 mm-1) and water productivity (0.485 kg m-3) were registered when irrigations were scheduled by drip at 0.6 Epan +100% N & K through fertigation.