Physiological responses of cotton to subsurface drip irrigation on heavy clay soil

Cotton in heavy clay soil with subsurface drip irrigation (SDI) @ 50, 75, 90, and 120 % of daily ET and conventional furrow irrigation showed a significant effect on phenology and yield. Plant height, number of branches, nodes and leaf area index increased with increasing amount of water in SDI and were even greater in furrow. However, leaf chlorophyll, dry matter percent of plant and roots decreased with increasing amount of irrigation. Leaf water potential and crop water stress increased whereas leaf photosynthesis decreased with decreasing level of irrigation. Lint yield on SDI at 75% of daily ET was as high as furrow and was accompanied by higher water use efficiency (WUE) (0.6274, 0.4785 and 0.3551 t/ML for SDI at 75 and 120% ET and furrow respectively).