Agricultural water management in the world during past half century

The present paper aims to estimate the areas equipped for irrigation and desirability of agricultural water management in the world. For this purpose, all necessary information was gathered from Food and Agriculture Organization and checked using World Bank Group. The selected 18 indices were analysed for all 26 regions in the area studied, and the extent of area equipped for irrigation to cultivated area was estimated by 2 different formulas and other 9 indices. In addition, an average index was calculated using various methods to assess region conditions for agricultural water management. The results show that Central Asia is the best region for agricultural water management and the value of relative error is less than 20%. The capability of irrigation and drainage systems was studied using other eight indices with more limited information. The results indicated that trial-and-error policies should be avoided and expert comments be applied to irrigation systems for any crop.