INFLUENCE OF VARIOUS SOIL MOISTURE-REGIMES ON YIELD AND QUALITY OF COTTON IN AN ARID ZONE

The results of three cotton irrigation experiments in the western Negev region indicate that by increasing the intervals between irrigations and by applying the first irrigation at the beginning of flowering, maximum yields of 1700-2100 kg/ha can be obtained with three irrigations. In all treatments except the one with four irrigations, about 0.31 kg of lint was produced for each 1 m3 of irrigation water. In the three driest treatments, where cotton suffered from moisture stress during various periods of growth, no differences in lint quality could be detected in comparison with wetter treatments. As long as there were clear drought symptoms, such as in the three driest treatments, additional irrigation increased the number of bolls/plant, while the average boll weight remained unaffected. Additional irrigation in treatments where there were no clear water stress symptoms did not increase the number of bolls/plant, but increased the average boll weight. © 1969, Cambridge University Press. All rights reserved.