Effect of drip irrigation on yield of cabbage ( Brassica oleracea L. var. capitata) under mulch and non-mulch conditions

Abstract

The experiments were conducted on the lateritic sandy loam soils of Kharagpur, West Bengal, India during middle of September–January for 3 years (1997–2000) to evaluate the economic feasibility of growing cabbage crop under drip irrigation with mulches. Actual evapotranspiration for cabbage crop was estimated by using the modified Penman method and net daily irrigation requirement was estimated after subtracting effective rainfall. Estimated irrigation requirement was supplied by a 4 l h −1 emitter for four plants with the drip irrigation system being operated from 70 to 101 min per day during the crop season. The average seasonal water requirement of crop was estimated to be 400 mm. The yields of the cabbage under 25 μm thick black plastic mulch (PM) were studied using three levels of drip irrigation which applied 100% (VD), 80% (0.8VD) and 60% (0.6VD) of the estimated irrigation requirement. The yield response under two organic mulches, rice husk with drip (VDH) and paddy straw with drip (VDS) were also studied. For comparison, furrow irrigated (VF) treatments were used and the study revealed 62.44% higher yield in case of drip (VD) as compared to furrow irrigation. Even higher yields were obtained for drip irrigation with PM (VD+PM), 111.72 t ha −1 as compared to 106.68 t ha −1 for (VD). The treatments VDH and VDS showed, respectively, 2.05 and 1.18% higher yield when compared with drip (VD) alone. The net seasonal income was estimated to be highest as US$ 4333 in case of treatment VD+PM. The highest benefit–cost ratio of 8.17 was obtained for furrow irrigation (VF) followed by 6.99 for drip (VD). The net profit per mm of water used was obtained to be highest (US$ 16.51) in case of drip irrigation (0.6VD) followed by US$ 16.32 under the treatment 0.6VD+PM. The highest yield per unit quantity of water used was 427.04 kg ha −1 mm −1 for the treatment 0.6VD+PM. The study reveals that drip irrigation has a definite role in increasing the productivity of cabbage.