Impact of different irrigation regimes under varied planting density on growth, yield and economic return of cashew (Anacardium occidentale L.)

To assess the effect of planting density and irrigation in cashew (Anacardium occidentale L.) during its critical growth stages such as flowering and fruit set on, growth, yield, water-use efficiency and farm income, a field experiment was initiated in a split-plot design in 2011 at Puttur, Karnataka, India. The main plot consisted of three planting densities namely, 5 × 4 m, 6 × 4 m and 10 × 5 m. The irrigation treatments were imposed in subplots as, irrigation at 60% cumulative pan evaporation (CPE), at 40% CPE, at 20% CPE, irrigation once in 15 days, soil and water conservation technique, and control (without any irrigation or soil water conservation technique). The results indicated that the growth, raw cashew nut yield and net income during 5th and 6th year of plantation of cashew increased with increase in planting density per unit area. The average increase in nut yield under high density planting ranged from 75 to 81% compared to normal density planting. Irrigation using drip system from December to March at 20% CPE and 40% CPE was beneficial to increase the nut yield by 53.5% and 34.1% compared to control. The yield increase under soil and water conservation practice was 12.9%, and 59.7% under irrigation once in 15 days. The increased planting density was beneficial to increase the net income and benefit–cost ratio. The deficit irrigation practices were useful to increase the water-use efficiency in cashew. Widely spaced trees showed increased water-use efficiency compared to high-density planting. Overall, the study demonstrated the usefulness of increased planting density and appropriate irrigation practices to increase yield and net income from cashew orchards.