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.