Optimum crop cultivation at different levels of irrigation water allocation (Case study: Qazvin Plain)

Abstract

Designing and implementing a crop pattern is necessary not only to cope with water deficit, but also to control the limiting factors and optimal utilization of available facilities, which have been addressed in many countries of the world. The current study was conducted at five levels of irrigation including I1, I2, I3, I4 and I5 (100, 90, 80, 70 and 65% of crop evapotranspiration) and at three different levels of cultivation including S1, S2 and S3 (current cultivated area, 10% increase in cultivated area and 10% decrease in cultivated area compared to current conditions). Optimum crop levels were estimated for each crops of crop pattern. The results show that the model in S2 allocates a higher level to strategic crops, and in S3 it allocates a higher level to higher-yielding crops. The S3I1 has the highest income among all scenarios. I2 increased economic productivity at an average level of 7.5% while maintaining income. Therefore, it is possible to allocate a lower amount of area and a lower amount of water, and to earn more income. Also, I4 and I5 levels are not recommended due to reduced income and yield. If there is a decrease in available water and I5 is reached, cropping tomato, beet and alfalfa are not recommended considering economic level.