Spatial And Temporal Distribution Of Water And Drought Disaster In Guangxi And Its Impact On Food Production

As a major agricultural country in developing countries,the core of China's national strategic development is inseparable from agricultural development and food security.Guangxi has a superior geographical location and unique water and heat conditions,but Guangxi's grain production ranks not high in total output or unit output in area,provinces and cities in China.While seeing that Guangxi has excellent water and heat conditions,we should also be aware of the risk that Guangxi is located in an area with a high incidence of meteorological disasters.Natural disasters,especially water and drought disasters,are still a factor affecting food production that cannot be ignored in Guangxi.Taking Guangxi as the research area,analyze the characteristics of water and drought disasters and grain production,and discusses the impact of water and drought disasters on grain production,which can provide scientific basis and valuable reference for the prevention and management of agricultural water and drought disasters.The data of grain production(sowing area,yield,yield)and water and drought disaster(affected area,disaster area,flood and drought disaster characteristics in 1978-2017,analyzed the characteristics of 14 prefecture-level cities,counties,in 1988-2017 and the characteristics of water and drought disaster based on the years of production rate and output reduction,and studied the sensitivity of grain production to water and drought disaster.The main research contents and conclusions are as follows:In(1)from 1978-2017,the sown area of Guangxi increased,and the sown area of grain crops decreased steadily.At the same time,the proportion of grain sown area accounting for the sown area also decreased year by year.Although the declining grain sown area in guangxi,the total grain output and unit output is the overall rising trend,but guangxi grain production still not fundamentally get rid of the weather,once encountered serious natural disasters,will cause of grain fluctuations,meet the policy of adverse to grain production is even worse.(2)The sown area of grain in 14 cities shows different trends,among which the largest change amount is Chongzuo,with extreme value ratio of 1.14,average annual decline range of19.300 ha / 10 a,is Qinzhou,extreme value ratio of 0.13 and average annual decline range of0.400 ha / 10 a.The change of grain yield is the largest guest,with the extreme ratio of 1.04,the minimum of Baise,and the extreme ratio of 0.43.The maximum change of grain output per unit area is Chongzuo,the extreme ratio of 1.50,the minimum is Guilin,and the extreme ratio of0.32.(3)Between 1978 and 2017,the average proportion of flood and drought disasters in Guangxi was slightly higher than the national average level.Among them,the drought and affected area of less and less,more and more floods.The prefecture-level city with the largest annual average flood-affected area and the largest disaster-affected area is Guilin City,and the largest annual average drought-affected area is Laibin City.(4)Years of severe flood reduction in Guangxi were 1994-1998,2001-2006,2008,2010-2011 and 2014;severe drought reduction were 1988,1990-1992,2003-2007,2009-2010.During the analysis of the flood changes in Guangxi,the 1994-2013 in 1996-1999,and 14 years in Guangxi,indicating the impact on grain production in Guangxi;4 in 11 drought on grain production was smaller than the flood and verified the results of Pearson.(5)The 1990 s was the period when food was most sensitive to disasters,followed by the1910 s,when the food sensitivity of the four years was alternately high and low.Of them,the21 st century,33.3% from the previous era.The analysis of disaster-causing factors can find that due to the influence of abnormal atmospheric circulation activities in the 1990 s,there were frequent disasters,and the weak disaster reduction ability in the 1990 s.Since the 21 st century,the development of science and technology has strengthened the disaster prevention and reduction capacity and reduced the food sensitivity to a historical minimum.But the rapid rebound in sensitivity after 10 years may be related to the reduction in grain income and the lack of enthusiasm.