Investigate the relationship determine effective rainfall in areas of high rainfall and low rainfall (Case Study Rasht and Daran)

Given the vital importance of water in human life, recognizing the effective use of rainfall and crop water requirement and economic planning are very important. Identifying and applying appropriate method for estimating effective rainfall, especially in rainfed has importance. In this study to determine the most suitable experimental method for estimating effective rainfall in rainfed Wheat, Barley, Peas and Lentils for high rainfall areas (Rasht in Gilan) as compared to areas of low rainfall (Daran in Isfahan) are discussed. In this study, five different experimental methods to determine the effective rainfall, including: methods of the Soil Conservation Service (SCS), reliable method, empirical, United States Department of Agriculture (USDA), and percentage method. The results shown that all methods used in effective rainfall in Rasht is useful. But if in Daran that a low rainfall area want determine the effective rainfall, it need to be pre-calibrated. Results have shown that the use of methods to prioritize the review in these two areas, methods for Rasht are SCS and the percentage and USDA were recommended in Daran. Since the amount and duration of rainfall is not controllable can be effective strategies to increase performance of precipitation and consequently precipitation. Including the reduction of surface runoff, water storage for times of low rainfall and reduced water depth plan for the cultivation of plants used in accordance with the precipitation regime.