The Influence Of North And South Qinling Extreme Drought In Agriculture

Under the background of global warming, the frequency of extreme drought is on the rise. Qinling Mountains are the dividing line of the southern and northern part in China. There exists difference between north and south of Qinling Mountain’s climate change.Agriculture is the most sensitive factor to sense to climate change, so explore the influence that extreme drought of the south and north of Qinling Mountain on agricultural production, which have great significance to controlling drought, releasing disaster and deducing and adapting to the negative impact of the extreme drought.This paper utilizes many data such as average temperatures, rainfall statistics and various cities crop yield data between north and south of Qinling Mountain from1961to2010, on the basis of analysis of the current drought research at home and abroad, processing the meteorological and agricultural production data by Excel、DPS、ARCGIS. Analyzing the agriculture condition between north and south of Qinling Mountain; Analyzing the characters of spatial and temporal variations of the north and south of Qinling Mountain Mountains;Using the surface humidity index, analyzing the characters of spatial and temporal variations of extreme drought, age and season between the north and south of Qinling Mountain Mountains; Analyzing the growing crops rainfall change and condition of crop growth period of extreme drought change, using the production separation, getting the crop growth period damage rate of extreme drought.The mainly conclusions of this paper are as follows:In recent50years, the overall of wheat area in Guanzhong region and rice area in Southern Shaanxi region fluctuated decline. Wheat yield per hectare a year in the middle with300.6kg/hm2rate rise, rice yield in each year to258.4kg/hm2rate rise, Due to the different types of crop yield increase, both Guanzhong wheat and Southern Shaanxi rice increase in total, total crop production is stable and the rising in stateThe annual precipitation between north and south of Qinling Mountain are declined, but Southern Shaanxi decline slightly larger than Guanzhong, the change of the two regions is synchronized. For the north and south of Qinling Mountain, the precipitation are downward in spring and autumn, but showed an upward trend in summer and winter. The distribution of rainfall is zonal that south hither than north, the spatial variation of the seasonal precipitation showing the spring and autumn precipitation gradually decreased from southeast to northwest, is the obvious zonal distribution, the rainfall spatial distribution of the basic performance is that from southeast to the northwest is low in winter, is the else zonal distribution.The frequency of extreme drought showing rising trends between north and south of Qinling Mountain, and changes is simultaneously, the rise of the extreme drought in Southern Shaanxi slightly larger than Guanzhong. The distribution of extreme drought shows that the North more than South. There are significant regional differences between north and south of Qinling Mountain’s extreme drought trends, showing an overall decreasing trend from the center to the surrounding.The average of extreme drought is difference. The Qinling Mountain Mountains north of cities in different years of extreme drought frequency in the1990s, and the first10years of the21st century is the modern extreme drought occurred the largest range of periods.There are different for frequency changes of extreme drought between north and south of Qinling Mountain, the frequency number showed a positive growth trend in spring, autumn and winter, but the summer is a negative growth, in southern Shaanxi is still positive growth.The frequency of extreme drought in Guanzhong area is smooth, there is no mutation point; the frequency became less from1979before and after to1993in Southern Shaanxi. In the cycle analysis, there exists25a and8a-cycle changes in Guanzhong, there are changes in the cycle25a and10a in Southern Shaanxi.The precipitation of crop growth is in the overall downward trend. The frequency of extreme drought in wheat49a growing season is increase in Guanzhong region, but in rice growing period showing high-low-high U-shaped change in Southern Shaanxi.The wheat yield shows a linear upward trend in Guanzhong, and the actual production of wheat and disaster loss rate was significantly negatively correlated. The municipality’s trend is upward, but off most disaster loss rate, and disaster loss rate fluctuations in the1980. Guanzhong region49a wheat growing season by the extreme drought caused wheat10a cut. The influence that wheat growing season by the extreme drought is more, especially10years of the21st century in Guanzhong region.The rice yield shows upward in Southern Shaanxi, and the actual production of rice in southern Shaanxi and disaster loss rate was significantly negatively correlated. The rice production showed an upward trend in the Southern Shaanxi’s cities. The rice growing season in50a is infected by extreme drought year is14a, but it cut in7a. There is difference between cities in rice growing when affected by the extreme drought.