| Millet,as an ancient crop originated in China,is nutritious and widely used.It is a kind of food that people often eat in daily life,and it is also a high-quality raw material for processing agricultural and sideline products.With the improvement of people’s living standards and the adjustment of dietary structure,the millet industry has a bright future.Liaoning Province is one of the main millet producing areas in China,and the sown area and its yield of millet are in the forefront of China.However,affected by global climate change,in recent years,the temperature in Liaoning Province has increased significantly,and the precipitation has decreased.So,there is an obvious contradiction between supply and demand of water resources.Besides,droughts have occurred frequently and constantly,seriously threatening millet production and causing huge economic losses.Therefore,it is urgent to understand the distribution and migration of millet drought disaster risk under the background of climate change,so as to guide millet production in Liaoning Province,avoid the risk of drought disaster and ensure national food security.Taking different growth periods of millet as the breakthrough point,this study established a drought disaster risk assessment technology applying in the whole process of millet growth.It based on the future global climate change scenario model and combined the crop growth model with the disaster risk assessment model.It aimed to explore the dynamic evolution characteristics of millet drought disaster risk in Liaoning Province under the background of climate change.This study will make up for the deficiency of the research of dynamic assessment of millet drought disaster risk and solve the key problem that drought frequently threatens national food security.The research results can be extended to other disaster types and regions in China,which is of great significance for improving the ability to cope with meteorological disaster risks in agricultural sector and achieving the goal of preventing disaster in scientific and precise way and resisting disaster in active way.The main research results of this paper are as follows:(1)The identification index SPRI of millet drought based on disaster process can accurately characterize the drought situation of millet in Liaoning Province.From 1960 to 2019,the drought of millet in Liaoning Province tended to intensify,but it was still dominated by mild drought,and severe drought was rare.Spatially,the frequency and intensity of drought in the western of Liaoning were relatively high and serious.(2)SPRI index can be used to assess the situation and the corresponding millet yield reduction rate can be used to determine the disaster damage coefficient of different levels of drought in different growth periods,which was used to characterize the drought intensity.Through combining the frequency of different levels of drought in different growth periods,a millet drought disaster hazard assessment model was constructed.The results showed that the study area was dominated by medium-high risk.High risk is in the west and north of study area.Low-risk is in the east and south of study area,and the extremely high risk area was mainly concentrated in the western of Liaoning.(3)The effects of different disaster intensity on the growth and development of millet were analyzed through the drought stress test of millet,and the parameters of CERES-Millet model were calibrated and verified by GLUE method.Then,based on the simulation results of CERES-Millet model,the loss rate of key physiological indicators at different growth periods of millet was calculated,and the drought disaster vulnerability curve of millet was constructed.The results showed that with the increase of the drought intensity of millet,the loss rate of its key physiological indicators at each growth period of millet also increased.(4)The drought disaster risk of millet at different growth periods in the study area was dynamically assessed by comprehensively considering the hazard of drought disaster-inducing factors and the vulnerability of millet drought disaster based on CERES-Millet model.The results showed that the drought disaster risk of millet at different growth periods showed a distribution feature,that is,high-risk in the northwest and low-risk in the southeast,and spread around with the center in the west of Liaoning.Through the correlation test between the yield reduction rate of millet and the drought disaster risk in different growth periods,the accuracy of the risk assessment results is verified.(5)The dynamic assessment model of millet drought disaster risk was used to assess the millet drought disaster risk in Liaoning Province under three different scenarios.The results showed that the millet drought disaster risk in Liaoning Province was increased as a whole compared with that in the historical period.The millet drought disaster risk in different growth periods were still high in the northwest and low in the southeast.Among them,the drought risk of millet under SSP245 scenario was the highest,followed by SSP126 scenario,and SSP585 scenario was the lowest.The center of gravity of drought is in the western of Liaoning,showing a trend of spreading to the southeast.The research results have important scientific value for Liaoning Province to ensure the safe development of agriculture,do a good job in drought disaster prevention and meteorological services,and strengthen stable grain supply. |
