Sensitivity of Ceres-maize simulated yields to biogeochemical components

Change in environmental conditions including climate change is already occurring and is expected to affect crop production. This has led to a need to assess the impact of such changes to crop production so as to develop the adaptation strategies to assure sustainable production and food security. Crop simulation models are adopted for this kind of studies, however, the models’ applicability varies with location, climatic conditions and purpose. For this study, CERES-Maize crop model sensitivity to climatic variables uncertainty and Nitrogen fertilizer was evaluated. Maize yields were simulated using a 31 years (1979-2009) climatic record for a range of important variables. The input ranges of variables were: Temperature (-2°C to +8°C), rainfall increment (25% to 200%), Carbon dioxide concertation (360 ppm to 720 ppm) and Nitrogen fertilizer (30 kg/ha to 180 kg/ha). The model was initially calibrated and evaluated for one and two years respectively. Sensitivity analysis was performed for one parameter level at a time while other parameters were fixed at their normal values. Sensitivity results showed high response to change in temperature (from 300 to 650) kg/ha, water (from 550 to 800) kg/ha, Nitrogen (500-1000) kg/ha and low sensitivity in Carbon dioxide concentration (550-600) kg/ha. It was concluded that CERES-Maize from crop model is sensitive to Nitrogen fertilization as well as to all selected climatic variables. Thus, the CERES-Maize crop model can be used for crop simulation studies and climatic impact assessments.