Irrigation scheduling and moisture conservation in water melon

Abstract

An experiment was conducted at the Agricultural Research Station, Mannuthy, Thrissur during the period from December 1998 to March 1999 to study the influence of levels of irrigation and moisture conservation methods on the growth and yield of water melon (Citrullus fanatus) grown in rice fallows. The experiment was laid out in randomized block design with three replications. The treatments consisted of combinations of four moisture conservation methods (control, application of paddy waste as surface mulch, uniform incorporation and bottom layer application @ 1/3 pit volume) and four levels of irrigation (IW /CPE ratio of 0.6, 1, 1.4 and farmer's practice of daily irrigation @ 20 lit pit"), The study revealed that incorporation of moisture conservation materials increased the growth attributes like length of vine, number of leaves per vine, leaf area and dry matter production and yield attributes like weight of fruits and number of fruits per plant. Among moisture conservation methods surface mulch and uniform incorporation of paddy waste were found to be superior in most of the cases. Watermelon responded very well to irrigation. Biometric characters (length of vine, number of leaves per vine, leaf area and dry matter production) and yield attributing characters (weight of fruits and number of fruits per plant) were favourably influenced by frequent irrigations. The fruit yield increased with increase in frequency of irrigation and was maximum at IW /CPE ratio of 1.4. Results of soil moisture studies revealed that incorporation of moisture conservation material' increased the soil moisture content, consumptive use and water use efficiency. The consumptive use increased with the frequency of irrigation. The top 15 cm of the soil layer accounted for the highest soil moisture

depletion. The depletion was more from the deeper layers in the drier regimes. Field and crop-water use efficiencies were higher in less frequently irrigated treatments. Higher levels of irrigation increased N, P and K content of leaves. No convincing change in leaf N, P, K content could be brought about by the incorporation of paddy waste. Economic analysis showed that incorporation of paddy waste could increase the net profit. Net profit as well as net return per rupee invested were the highest with scheduling irrigation at IW/CPE ratio of 1.4. Among the treatment combinations, the best combination was surface application of paddy waste with irrigation at IW/CPE ratio of 1.4 followed by the combination of surface mulching and fanner's practice of daily irrigation.