The productivity of soil largely depends on the optimum conditions of farmingincluding the water quality. With the proper pH values of the water-soil moisture maintained during the time of farming leads to absorption of right amount of minerals to the plant body which increases the productivity of the crop. Under normal practice, it is often found that the pH value of the irrigational water overlooked and hence the optimum conditions are maintained. In this article, a noble approach is taken to regulate the valve response so that this pH mismatch between the supplied water and soil can be rectified and the most suitable value can be preserved. While with the use of Penman-Monteith (PM) method, the water loss due to evapotranspiration is determined and water valves are operated to supply the necessary volume to eliminate the crop-water stress, an exhaustive fuzzy rule-base model is developed to control the opening and closing of the valves based of the pH value of the supplied water to maintain the optimal values. On evaluation of the designed model, it is seen that the PM model is successful is determining the water loss and the on encountering a surge in the acidic levels of the supplied water, the valve constricts to slow down the water flow and it inflates while the water is alkaline is nature. Thus the objective of the model is properly served and significant results are obtained.