Impact Assessment of Climate Change on Maize Yield of Long An Province (Vietnam) under B2 Scenario by DSSAT

Nguyen Ang Thuy An, Tran Duong Thien Loc, Nguyen Ky Phung

The 3rd EnvironmentAsia International Conference on “Towards International Collaboration for an Environmentally Sustainable World”, June 17-19, 2015, Bangkok, Thailand

Maize is a very important food and economic crop not only in Vietnam but all over the world and the influence of climate change on it has been shown in several previous studies with different models. Basing on the climate change scenario B2 generated by Ministry of Natural Resources and Environment, the maize yield of Long An Province in 2020, 2030 and 2050 was simulated by crop model DSSAT. Input data for DSSAT consists temperature, soil characteristics, climate, fertilizer, irrigation, farming technology and management and was collected from 2003 to 2010. At the first step, the results of maize yield simulated from 2003 to 2010 by DSSAT examined on two fields which had different soil characteristics were compared to the real yield values in order to calibrate the model. Then, a basic year would be selected and simulation of maize yield in 2020, 2030 and 2050 would be based on climate data of this year under B2 scenario. After comparison, Pearson r correlation between simulated and real yield values on two fields were both estimated r > 0.8, which meant that model calibration turned out to be unnecessary and DSSAT was an appropriate model to be used in simulating maize crop yield in Long An Province. The results from the next steps showed that increase of temperature and change of precipitation would cause decrease in maize yield in winter-spring and summer-autumn crops. In general, the yield would begin to decrease sharply from 2030 to 2050. Inferring from its lower crops yield, summer-autumn crops would be affected more significant than winter-spring ones. According to B2 scenario, the highest decreasing yield was forecasted 8,9% for summer-autumn crop and 6,5% for winter-spring crop in 2050. There were differences of changing maize yield between two fields which had different soil characteristics. Basing on the results obtained, this study proposed solutions in order to maintain and improve maize yield in climate change condition in the future.

Keywords: DSSAT; Maize crop yield; Simulation; B2 scenario