agrotecnologia

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Simulation Study on Climate Change Impact and Management Options for Sorghum [Sorghum bicolor (L.) Moench] Production in the SemiArid Northeastern Ethiopia

Abebe Misganaw, Adem Mohammed

Climate change is one of the current issues that severely influence all climate sensitive sectors like agriculture. Crop management options are needed to minimize the impact and sustain regional food production.The objectives of this study were (1) to calibrate and evaluate the CERES-Sorghum Model of DSSAT (V4.7) for simulating phenology, growth and yield of sorghum (2) to assess projected climate changes (2030s and 2050s) in the study area (3) to simulate impact of projected climate change on phenology, above ground biomass and grain yield of sorghum (4) to explore the possibility of employing supplemental irrigation and sorghum cultivars as management options. The CERES-sorghum model in DSSAT (V4.7) was first calibrated and evaluatedfor sorghum cultivarGirana-1 using experimental data. Daily weather variables (1980–2009) that include rainfall, maximum temperature, minimum temperature and solar radiation) were obtained from the nearest weather station at Sirinka, Ethiopia. The 17 CMIP5 GCM out-puts run under RCP 4.5 and RCP 8.5 for 2030 s and 2050 s time slice were downloaded for the target sites from CIAT’s climate change portal (http://ccafs-climate.org/) and downscaled to the target sites using Markism GCM. The model calibration result indicated that cultivar specific parameters within the model were reasonably adjusted. The model evaluation result also showed that the model simulated phenology, grain yield and above ground biomass yield with high accuracy with minimum RMSE of 1.83 for anthesis, 3.3 for physiological maturity, 685.6 for grain yield, 477.8 for above ground biomass yield. The analysis of future climate showed thatmean maximum temperature is projected to increase by 1.40C and 1.90C by 2030s and 2050s time periods, respectively under RCP 4.5 and by 1.50C and 2.50C by 2030s and 2050s time slice respectively under RCP 8.5. Rainfall, it is predicted to increase by 1.5% and 4.5% in 2030s and 2050s, respectively under RCP 4.5 and by 3.7 and 3.2 % increase in 2030s and 2050s, respectively under RCP 8.5. Phenology of sorghum is predicted to significantly (P < 0.05) decrease in 2030s and 2050s. However, grain yield of sorghum is predicted to significantly (P < 0.05) increase in 2030s and 2050s. The simulation result also showed that grain yield of sorghum will be substantially increased using supplemental irrigation and long maturing cultivars in future climate condition.