Quantitative Assessment Of Agricultural Drought Loss Risk For The Region Based On The Test And Simulation

With the construction and development of hydraulic enterprise for 60 years, hydraulic work has made progress in each city of Anhui province. However, the disaster of drought has the trend of frequency state, expanding scope and aggravating loss. Therefore, this study adopted Huaibei Plain of Anhui Province as the empirical area to evaluate quantitatively loss risk and drought-resistance level of agricultural drought, the yields of wheats was simulated based on the tests, and combined with the actual yield of wheats, agricultural drought loss risk and the drought resistance ability was assessed quantitatively. The results of the study were presented as follows:(1) According to the experimental observations, the formula of groundwater contribution was established based on the Accelerated Genetic Algorithm(AGA). From meteorology and groundwater depth observations on five stations (i.e., Dangshan County, Suzhou City, Bozhou City, Fuyang City, and Bengbu City in Huaibei Plain of Anhui province), groundwater consumption in Huaibei Plain of Anhui province from 1975 to 2007 was estimated. The water balance principle was adopted to estimate actual evapotranspiration of wheats from 1975 to 2007 in combination with the data of groundwater consumption, rainfall and estimated evapotranspiration of wheats. The parameters of crop water production functions were calibrated according to the observations and AGA. Thus, crop water production function of wheats in Huaibei Plain of Anhui province was established. On these grounds, wheats yields under natural conditions at the five areas of the five stations in Huaibei Plain of Anhui province from 1976 to 2007 were reckoned.(2) In the course of exploration of analysis methods of risks of small samples, information diffusion was improved wielding cross-validation and AGA, which can raise effectively the precision of the estimated frequency densities, and quantitative evaluation model of drought loss risks based on cross-validation and information diffusion was built. In view of the above, drought loss risks of wheats under natural condition and distribution maps of agricultural drought loss risks in Hubei Plain of Anhui province were obtained. Results from quantitative risk assessment of agricultural drought loss under natural conditions showed that the orders of the expectance of the yield reduction rates of drought from the greatest to the smallest were Suzhou City, Bozhou City, Dangshan County, Fuyang City, Bengbu City in Huaibei Plain of Anhui province. The yield reduction rates of drought in the northern regions of Huaibei Plain of Anhui province were big, while those in the southern regions were small.(3) Drought loss risks of wheats under actual state and distribution maps of agricultural drought loss risks in Huaibei Plain of Anhui province were obtained on the basis of actual wheats yields in Huaibei Plain of Anhui province. Quantitative assessment of agricultural drought loss risk under actual conditions showed that the orders of the expectance of the yield reduction rates of drought from the greatest to the smallest were Huainan City, Suzhou City, Bozhou City, Bengbu City, Fuyang City, Huaibei City. The pattern of drought loss in Huaibei Plain of Anhui province was that severe drought loss is in the south-central regions of Huaibei Plain of Anhui province, while light drought loss in the western and eastern areas.(4) By comparing distribution maps of drought risks under natural condition with those under actual conditions, the differences of drought resistance ability among cities were analyzed qualitatively. And from the definition of drought resistance ability, the comprehensive drought resistance ability index was described as the expectance of drought loss saved by drought resistance ability. Based on the previous calculation results of drought risks under natural and actual condition, the distribution map of the comprehensive drought resistance ability index in Huaibei Plain of Anhui province was obtained. The results reflected that the drought resistance ability in the south-central areas of Huaibei Plain of Anhui province was the least among cities in Huaibei Plain of Anhui province, while the ability in the northeast part was the strongest. Through the analysis of factors of influence on drought resistance ability, it was discovered that cultivation ratio of the dry crop and temperature were the main influence factors.