Risk Assessment Of Cotton Drought Disaster In Northern Xinjiang

Drought disaster threatens agricultural production and affects the healthy development of economy.It is of great theoretical significance for agricultural decision-making,agricultural disaster prevention and reduction to study the spatial and temporal evolution of agricultural drought and its drought risk assessment and regionalization for cotton.Based on the daily meteorological data of 26 meteorological stations in Northern Xinjiang and the relevant data of cotton production in Northern Xinjiang,the temporal and spatial distribution of agricultural drought during cotton growth period in Northern Xinjiang was studied,and the risk model of drought disaster in Northern Xinjiang was established,and the risk assessment and zoning of Cotton Drought disaster in Northern Xinjiang were carried out..The main conclusions are as follows:(1)The water demand of cotton in different growth stages and irrigation water demand in Northern Xinjiang generally showed a downward trend,especially in flowering and boll forming stage;Climate factors exhibited great influence on crop water demand and irrigation water demand at each growth stage of cotton,among which rainfallwas the most influencing factor,followed by relative humidity and water vapor pressure.In spatial distribution,the crop water requirement of each growth period of cotton decreased gradually from the west to the East,and the irrigation water requirement was low in the surrounding area and high in the central area.The results of climate cause showed that the water demand of cotton at all stages of growth was positively correlated with sunshine hours and average wind speed,and negatively correlated with rainfall and average relative humidity,It was negatively correlated with rainfall and average relative humidity(p < 0.01).The irrigation water demand of cotton at all stages of growth was positively correlated with the average temperature,sunshine hours and rainfall,and negatively correlated with the average relative humidity and rainfall,and reached a very significant level.(2)The temporal and spatial variation characteristics of drought intensity,frequency and ratio of drought stations in different regions of Northern Xinjiang in recent 56 years were analyzed.From the changes of the ratio and intensity of drought stations in each growth stage of cotton,it showed an upward at first and then a slight downward trend,especially during the boll opening stage,the upward to downward trend was more obvious.According to the spatial distribution of drought intensity in different growth stages of cotton,the drought intensity gradually increased from West to North.The areas with high drought intensity were located in Dabancheng in the south of Northern Xinjiang and Altay in the north.From the spatial distribution of drought frequency in different growth stages of cotton,the frequency of severe drought was higher in Northeast of Northern Xinjiang at seedling stage.The frequency of severe drought in Karamay and Nileke was higher in budding stage and flowering and boll forming stage of cotton,and the frequency of severe drought and special drought in boll opening stage was lower than the other two growth stages.From the perspective of drought levels,in most areas of northern Xinjiang,the frequency of severe droughts during the cotton growth stage was higher than that of other grades of droughts,and the frequency of extreme droughts was the lowest.(3)Using analytic hierarchy process,the four factors in the model were evaluated.The high and secondary high risk areas of cotton growth period in Northern Xinjiang were mainly in the northwest of Northern Xinjiang.From the analysis of vulnerability,exposure and disaster prevention ability,the high and sub high vulnerability areas of cotton in Northern Xinjiang are mainly distributed in the southeast of Northern Xinjiang.The high exposure areas of cotton in Northern Xinjiang were mainly located in the southwest of Northern Xinjiang.The high risk areas of cotton in Northern Xinjiang are distributed in the western part of Northern Xinjiang;the rest belongs to low and sub low risk areas,which are located in the southern and northwestern parts of Northern Xinjiang,with stable production and small cotton planting area.