Estimation evapotranspiration by Penman Monteith method and its water require in Isfahan province

Water productivity Increase is one of the water management solutions in agriculture and increasing its efficiency. The accurate determination of plants water requirement and the accurate value estimate of evapotranspiration is essential for improving water productivity in irrigation network that it can help to improve water management in agriculture. in this research such climatic elements as temperature,rainfall and daily relative moisture have been calculated within the statistic era(1993-2000).To put it into practice calculate-xlsx program in excel is used.The amount of evaporation and daily perspiration was also calculated depending on Petman Monteith method.water and rainfal requirement for growing saffron in different seasons were specified as well.The results of this study indicate that in the western and southwest stations in the province the temperature needed to get the necessary degree of the plant would not be accessible.considering the fact that procuring necessary amount of temperature is the first factor for the growth of saffron, thus such stations are not suitable for planting saffron. saffron grows during the seasons of October (Mehr) and May (ordibehesht).During the period of growing saffron Ardestan station with the average of 528/1 mm and kashan station with the average of 279 mm calculated as the most and the least amount of water requirement bases respectively.In Ardestan station the average of 407 mm and in Golpaygan station the average of 107 mm also calculated as the most and the least amount of annual irrigation respectively.