Simulation of moisture regimes effect on maize (Zea mays) growth and yield in Kermanshah region by CERES-Maize model

One of the reliable approaches to study the effects of management on agricultural production is using crop growth models. In order to determine the effect of different levels of irrigation on the growth and productivity of grainy maize cultivars and validation of the CERES-Maize model, an experiment was conducted as split plot at the experimental field of Campus of Agriculture and Natural Resources, Razi University, Kermanshah, Iran, during 2017-2018. Main-factor was three irrigation regimes (IR) included supplying 130, 100, 70% water requirement (IR130%, IR100% and IR70% respectively), and sub-factor included three maize cultivars (SC704, Simon and BC678). The evaluated traits were development stages, leaf area index, total dry weight, grain yield and daily evapotranspiration. Model validation results showed that nRMSE values of SC704, Simon and BC678 for days to anthesis were 2.8, 1.7 and 1.9%, for days to physiological maturity were 4.2, 4 and 4.6%, for total dry weight were 9.6, 7.0 and 13.4% and for grain yield were 12.9, 5.2 and 6.1% observations, respectively. The nRMSE for daily evapotranspiration was 12.9 to 23.5% observations. By reducing the water content available in the IR70% treatment compared to other irrigation treatments, the simulated cumulative evapotranspiration gradually moved away from the measured evapotranspiration, so that in the water deficit stress treatment, the model simulated the amount of evapotranspiration more than farm conditions. Overall, the results of validation showed that the CERES-Maize model was able to predict response the growth and yield of maize cultivars under different soil moisture conditions with appropriate accuracy, therefore, it can be used to evaluate the impact of different irrigation regimes in the maize fields.