African and Mediterranean Agricultural Journal - Al Awamia (Mar 2022)
Application of FAO-AquaCrop model in evaluating climate change impact on wheat productivity in the rainfed Zaer area
Abstract
Accurate crop development modelling is important in planning rational use of water resources and crop management, along with evaluating the effects of climate change on crop productivity and predicting yields. This study aims at modelling winter wheat productivity under different climatic scenarios and models, in a Moroccan rainfed agriculture site using the FAO AquaCrop model. The study site was a one-hectare experiment plot located in the Marchouch plateau in the North-western Morocco. The model was calibrated using field parameters of the crop growing cycle, the soil characteristics, the crop management and the observed yield for a period covering three cropping cycles (from 2014/2015 to 2016/2017) using daily rainfall and temperature data. The calibrated model was then used to simulate wheat productivity in the study site for short-term (2020-2030) and medium-term periods (2040-2050) compared to a reference (1985-2005). Two Representative Concentration Pathway scenarios (RCP 4.5 and RCP 8.5) were considered for three General circulation models (CNRM, EC-EARTH, and GFDL) to derive the average model outputs with focus on the crop yield, crop growing cycle and evapotranspiration. The results showed a good model calibration, with coefficient of determination R2 of 0.84, Nash-Sutcliffe indicator of 0.71 and Willmott index of 0.94. Simulations showed that under RCP 4.5 a short-term yield drop of 5.94%, a medium-term crop cycle decrease of 15 days and evapotranspiration reduction of 20mm. Meanwhile, the model predicted under RCP 8.5 a medium-term yield drop of 12.9%, a crop cycle decrease of 13 days and evapotranspiration reduction of 46mm. Overall, simulation results showed that AquaCrop model is suitable for simulating the effects of water and climatic stress on crop productivity in rainfed agricultural areas, which could help decision making in terms of water productivity and crop adaptation under future climate trends in the semiarid conditions.
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