Risk Evaluation And Prediction Of Maize Drought In Liaoning Province Under Climate Change

Drought disaster is mainly caused by the imbalance of soil water and crop water demand.Moreover,it has the characteristics of wide influence range,long influence time and frequent occurrence.It is a meteorological disaster that has a direct impact on crop yield,and the impact on agriculture is the most obvious.In recent years,with the global warming and the intensification of extreme climate events,the frequency,intensity,scope and duration of drought disasters have increased.Liaoning Province is an important grain production base in China,mainly planting corn.If drought disaster occurs during the growth period of maize,it will lead to serious yield losses and even no harvest.Therefore,the drought disaster risk assessment and drought risk prediction of different climate change scenarios in Liaoning Province are carried out.The research results can provide theoretical basis and scientific guidance for the formulation of policy on agricultural disaster prevention and mitigation in Liaoning Province.This thesis takes the corn drought disaster in Liaoning Province as the research object,starting with the four factors of hazard,vulnerability,exposure and emergency response ?recover capability,through Max Ent model,combined weighting method and natural disaster index method,this thesis constructs the index system and model of maize drought risk evaluation in Liaoning Province.In addition,this thesis analyzed the temporal and spatial distribution characteristics of maize drought in Liaoning Province,and further studied the comprehensive risk evaluation of maize in Liaoning Province.Eventually,this thesis predicts the climate change characteristics and drought characteristics from 2020 to 2100 under the development scenarios of SSP1-2.6?SSP2-4.5 and SSP5-8.5.The main research results are as follows:(1)The distribution of precipitation and temperature in each month of corn growing season in Liaoning Province is uneven.For almost 60 years,the temperature in each month of corn growing season has an increasing trend,and the interannual variation of precipitation is great.The temperature is low in the northwest and high in the southeast of Liaoning Province;On the contrary,there is less precipitation in the northwest and more precipitation in the southeast.(2)For almost 60 years,the frequency,intensity and range of drought in each month and growing season of maize showed an increasing trend,especially after 1980.The northwest of Liaoning Province faces higher drought risk,while the southeast of Liaoning Province is lower,and the drought risk has a gradually decreasing trend from northwest to southeast.(3)In terms of spatial distribution,the drought hazard in the northwest of Liaoning Province is high in corn growing season and each month,while it is relatively low in the southeast.Therefore,under the situation that the risk,vulnerability and exposure of drought disaster in the northwest of Liaoning Province are high,but the ability of disaster prevention and reduction is low,there is a phenomenon of high comprehensive risk of corn drought in the northwest of Liaoning Province.(4)From 2020 to 2100,the average temperature and precipitation of corn growing season and each month showed an increasing trend.The drought frequency and intensity are different under different scenarios.SSP5-8.5 is the highest,followed by SSP2-4.5 and SSP1-2.6 is the lowest.The hazard of drought in the northwest of Liaoning Province is high,while the hazard of drought in the southeast of Liaoning Province is low.With the global warming and the improvement of development,the risk of drought in Northwest Liaoning is gradually increasing.In terms of spatial distribution,the northwest of Liaoning Province faces high drought risk,while the southeast of Liaoning Province has low drought risk.