Physiological and yield response of okra (Abelmoschus esculentus Moench.) to drought stress and organic mulching

Abstract: A field experiment was carried out on okra by imposing water deficit and using organic mulches during spring-summer of 2009 and 2010 at Indian Institute of Vegetable Research, Varanasi, India. The treatments comprised of three levels of irrigation scheduling (5, 10 and 15 days intervals) and three level of mulch (pea straw, dry grass mulch at 7.0 t ha^-1 and ?no mulch?). Significant differences on physiological and yield attributes were observed in various irrigation treatments and organic mulches. Organic mulching enhanced the stomatal conductance and photosynthesis by 127-154% and 50-59%, respectively over no mulch. Similarly, there was 16 and 33% reduction in photosynthesis, and 33 and 36% reduction in stomatal conductance in 15 days irrigation scheduled plant as comparison to 5 and 10 days schedule, respectively. The maximum photosynthesis and stomatal conductance was registered with irrigation at 10 days coupled with organic mulching. Similarly, irrigation at 5 or 10 days recorded 40.3 and 45.6% higher pod yield, respectively over longer intervals. Significantly higher yield was noticed in both organic mulches over no mulch. Maximum pod yields (103.55 and 116.73 q ha^-1) were recorded respectively, with irrigation at 10 days interval and mulching either with pea straw or dry grass. Mulched plants exhibited very proportional allocation of drymatter in various plant parts. The maximum water use efficiency of 351.60 kg ha^-1cm^-1 was recorded in treatment comprising irrigation scheduling at 10 days interval and mulching with dry grass.