IRRIGATION SCHEDULING THROUGH WATER PRODUCTION FUNCTION FOR RABI BRINJAL WITH SURFACE AND DRIP IRRIGATION METHODS

Studies were conducted with brinjal during rabi with surface and drip irrigation methods at Gujarat Agricultural University farms in South Gujarat region in different years. All the studies were monitored under a single technical program for the sake of uniformity. Water Production Functions (WPF) were developed for all the studies by fitting the data into 12 different established functions and the best fit function based on the maximum value of coefficient of correlation ‘r 2 ’ and minimum standard error value ‘SE’ was adjudged as the required WPF for the crop. Studies with surface & drip methods depicted exponential association (2) and MMF functions respectively. Based on the developed WPFs, the corresponding requirement of water was worked out for different yield targets for the normal irrigation water availability condition, and also for 10%, 20%, 30%, 40%, & 50% deficit water availability conditions owing to variability in rainfalls. Irrigation scheduling was done for different water availability conditions with both the irrigation methods. Water use efficiency was also worked for all the corresponding yield and water requirement values. This new approach will enable the irrigator to have flexibility of either using limited water in case of low water availability or getting more production with normal water availability.