Study on Periodical Water Stress in Drip Irrigated Rabi Castor with and without Mulch under South Gujarat Condition

Abstract

To assess suitable water stress period for Rabi castor, a field experiment was conducted during season of 2008-09 to 2010-11 at Soil and Water Management Research Farm, Navsari Agricultural University, Navsari (Gujarat) in FRBD design with three replications. The treatments consisting combination of mulching (M) viz., M₁: no mulch, M₂: black plastic mulch (25μ thick, 40 % coverage) and water stress period imposed from 50 per cent spike initiation stage (S) i.e., S₁: No stress, S₂: 20 days, S_3: 30 days and S₄: 40 days along with two surface controls i.e., with and without mulch irrigated at 0.8 IW/CPE ratio. The results indicated that the treatment M recorded significantly higher values of yield attributes viz., length of main spike (MS), length of effective main spike (EMS) and number of capsules/EMS as compared to treatment M. Among the water stress period, treatment S₁ recorded significantly higher values of EMS as compared to S₄, but it remained at par with S₃ and S₂. All the yield attributes of castor were not differed significantly due to M x S interactions. With respect to control v/s rest analysis, it was turned out to be significant on leaf area and MS only. In both the cases, control mean was significantly higher than drip mean. Mulching with black plastic significantly increased the seed yield of castor whereas periodical stress failed to exert significant influence on seed yield. The results implies that imposing water stress of 20 days period without mulch and 40 days with mulching after 50 per cent spike emergence did not reduce the seed yield of castor significantly. Ultimately, this resulted in additional saving of irrigation water without reduction in seed yield of castor.