Seasonal ARIMA Model for Pomegranate Evapotranspiration

The study was carried out for stochastic modeling of reference crop evapotranspiration values estimated by Penman-Monteith method from daily records of climatic parameters. Seasonal ARIMA modeling was performed for the generation and forecasting of weekly ETr values. The steps viz. standardization and normalization of time series variables, identification of the models, determination of the parameters of selected models, diagnostic checking and selection of the best model were performed for fitting the models. The ARIMA(1,1,0)(1,0,1)52, ARIMA(1,1,1)(0,1,1)52, ARIMA(1,1,1)(0,1,1)52 and ARIMA(0,1,1) (0,1,1)52 models were selected for forecasting and generation of weekly ETr values. The forecasted water to be applied were estimated from the crop coefficient, wetted area, total area of the tree and efficiency of the drip irrigation system for the pomegranate tree of 1st to 5th year age. These are: for Solapur station-3.1, 7.1, 19.5, 27.3 and 35.4 litres/day/tree; for Ahmednagar station -2.8, 6.5, 17.7, 24.8, and 32.2 litres/day/tree; for Pune station -2.5, 5.7, 15.9, 22.3, and 28.9 litres/day/tree; for Nasik station 3.3, 7.7, 21.5, 30.18, and 39.4 litres/day/tree.