Calibration and verification AQUACROP plant model to simulate the performance of three different wheat varieties under drought stress

Optimal use of available water resources and their management is very important according to modern science. This has led to the importance of using plant models to study the effects of low water on agricultural yields. In order to investigate the effect of moisture stress on yield and growth traits in three cultivars of horizon, clear and narin and weeding and validation of vegetative model AQUACROP for these cultivars were performed in 96-97 crop year on a research farm located in Birjand. The research was conducted in the form of a factorial randomized complete block design with 6 treatments and three replications. Irrigation treatments included 100 (control treatment), 75 (medium stress) and 50 (severe stress) percentage of wheat water requirement and 3 other treatments related to two new cultivars of Ofogh and Narin and one old and native cultivar Roshan. The results of the mean comparison of the mean mean of the simple effect of moisture stress, the simple effect of cultivars and the interaction effect of stress on different cultivars were significant in different traits. After analyzing and comparing the average plant traits of the AQUACROP plant model for stresses of 100 and 75%, the water requirement was measured in two parameters of grain yield and biomass. After the validation stage, the model validation model was performed with 50% water stress. The results of the model validation showed that the model calculations showed a close and acceptable simulation value compared to the measured value of grain performance according to NRMSE and R2 evaluation indicators. Also, to ensure the accuracy of the model, using the measured performance data, the bright figure in the 2009-2010 crop year was validated by changing the re-meteorological data. The NRMSE index value of the simulated and measured grain mass for the mean moisture stresses of 100 and 75% in the horizontal and horizontal digits of Rosin, Narin and Narin cultivars was 0.99, 0.88 and 1.51%, respectively. These values were observed in the model validation in 50% stress to 1.49, 3.14 and 0.88%, respectively. According to the values calculated in the statistical indicators, it can be concluded that the model can provide us with an acceptable efficiency for measuring different wheat cultivars, which is very important in the region due to the high and increasing number of different wheat cultivars.