Research On The Changing Trend And Matching Characteristics Of Agricultural Water And Soil Resources In Guanzhong And Their Impact On Food Production

Guanzhong area,located in the middle of Shaanxi province,is one of the ancient areas with a very long history of agricultural production in China.Its agricultural grain output accounts for about 65%of Shaanxi province,and its GDP and population account for about 70%and more than 60%respectively.It is the base of Shaanxi province's agricultural grain production and the center of its social,political and economic development.The natural environment of Guanzhong area determines that it is located in semi-arid and semi humid area,and more than 98%of the agricultural cultivated land is dry land,and the evaporation is far greater than its precipitation.Based on the area of cultivated land for agricultural production,the average amount of water resources per mu of cultivated land in Guanzhong area is more than 300 m3,which is about 40%of the average amount of water resources per mu in Shaanxi province and less than one-fifth of the nation.Therefore,in the process of agricultural production in Guanzhong,water resources and agricultural cultivated land are two constraints on its development,and the matching level between them directly determines the comprehensive utilization efficiency of agricultural water and soil resources in Guanzhong,which checks and balances the input factors of agricultural production,and then directly affects the trend of agricultural grain production.The reasonable utilization demand of agricultural water and soil resources and the sustainable development of agriculture in Guanzhong are practical problems that must be faced correctly in the process of agricultural production.In this study,the Guanzhong area of Shaanxi province was selected as the research area.According to relevant statistical data and actual investigation data from relevant departments,this paper combines climatology,geography,ecology,agriculture,statistics and other relevant methods and theories,and comprehensively applies the method of theoretical analysis,quantitative analysis and qualitative research.Based on the quantitative calculation and theoretical research on the water and soil resources and agricultural grain production in Guanzhong area,this paper analyzes and evaluates the influencing factors and trend changes of agricultural grain production in Guanzhong area through the quantitative calculation and theoretical research on the trend change of water resources status,the utilization demand of agricultural water and soil resources and the matching pattern of agricultural water and soil resources objective research analysis.The main research contents and conclusions are as follows:(1)Spatial and temporal distribution and trend change of water resources in Guanzhong.By calculating and studying the dynamic change of precipitation,surface and groundwater resources in Guanzhong area,the spatial and temporal distribution characteristics of water resources in this area are analyzed,and the total amount and change trend of water resources in the area of research are evaluated and studied.Due to the arid climate in this region,the spatial and temporal distribution of water resources is very different.From the perspective of geographical distribution,the precipitation in the south of Guanzhong is obviously greater than that in the north of Guanzhong,and the precipitation in the west of Guanzhong is obviously greater than that in the east of Guanzhong.Taking the Wei River as the boundary,the surface water in the south of the Wei River is obviously richer than that in the north.After calculation and analysis by combining statistical theory and Mann-Kendall trend and test analysis method,it can be seen that water resources in Guanzhong vary greatly in regional distribution and are highly uneven in time and season,and are generally in a state of shortage.In this region as a whole,the dispersion degree of annual precipitation is relatively concentrated and the variation is relatively gentle,and the annual precipitation in Guanzhong region is in the trend of decreasing.(2)Change of utilization demand and optimal allocation of agricultural water and soil resources in Guanzhong.According to the utilization demand of agricultural water resources in Guanzhong,the statistical data from 1980 to 2018 were used to analyze and study the trend of agricultural water resources utilization in Guanzhong.Based on the data from 2000 to 2018,the changes of agricultural water use of the five cities and one district in Guanzhong were discussed and analyzed respectively.The results show that the agricultural water use in Guanzhong has been in a downward trend.Based on the analysis of agricultural water consumption in Guanzhong from 2000 to 2018,the average annual irrigation water consumption in Guanzhong was 2.55 billion m3,and the average annual agricultural water consumption was 3.216 billion m3.Among them,irrigation water accounts for respectively 80%,57%and 52%of the annual agricultural water consumption in Guanzhong,the total water consumption in Guanzhong,and the average annual water consumption in Shaanxi province.The average annual agricultural water consumption in Guanzhong and that in Shaanxi accounted for 64%and 52%respectively.After analyzing the forecast of Guanzhong's agricultural water demand(the primary industry),it is concluded that 50%of the agricultural water demand of Guanzhong in 2020 will be 4.858 billion m3,and 75%will be 4.982 billion m3.In 2030,50%water demand is 4.486 billion m3,and 75%water demand is 4.901 billion m3.According to the terrain elevation of water resources distribution,the water supply capacity of water conservancy projects and the utilization demand of agriculture for water resources in Guanzhong,this paper puts forward and analyzes the water resources distribution network system of "three lines and ten points" with the Wei River as the central channel,and makes part of the optimization calculation based on the mathematical model of water resources distribution calculation research.(3)The trend of the dryness of agricultural cultivated land resources in Guanzhong area.By selecting the data of the agricultural cultivated land from 1985 to 2017,the trend of agricultural cultivated land resources is analyzed.According to the remote sensing data of the change of land in use in 1990,2000,2010 and 2017,through AcrGis10.2 system interpretation and data processing,the paper analyzes the changes in space and time of the cultivated land area and agricultural area in Guanzhong plain.The trend of agricultural drought in Guanzhong was discussed and analyzed.(4)Study of the matching of agricultural water-land resources in Guanzhong.On the basis of discussing the meaning of agricultural water resources and the natural attribute of water-land resources,this paper studies the theory of time matching and space matching of agricultural water-land resources matching,and puts forward its own argument theoretically according to the concept of agricultural water and soil resources matching.It is pointed out that in the process of agricultural production in Guanzhong,the growth of more than half of the farmland crops mainly depends on the "blue water"resources.The matching pattern of agricultural water-land resources in Guanzhong was studied with the support of AcrGis10.2 system,and the main reasons for the difference in the matching degree of agricultural water and soil resources in Guanzhong region were analyzed.The results show that the matching degree of water and soil resources in the southwest of Guanzhong is much higher than that in the northeast of Guanzhong.In terms of administrative regions,Baoji has the highest matching degree,followed by Xi'an,Weinan,Xianyang and Tongchuan.(5)Influencing factors of agricultural production in Guanzhong.Principal component analysis(PCA)and principal component regression(PCR)were used to analyze and study the influencing factors of agricultural production in Guanzhong.According to the environmental conditions and production input of the agricultural soil and water resources and the agricultural production in Guanzhong area,the contribution rate of each factor was calculated by combining PCA analysis method and PCR regression mathematical statistical analysis model,and the primary degree and contribution of each factor condition to agricultural production in Guanzhong were quantitatively analyzed.This paper also discusses and analyzes the influence of cultivated land,agricultural irrigation,human resources,means of production,natural disasters and other factors on agricultural grain production in Guanzhong.(6)Changing rules of agricultural and grain production in Guanzhong.By using the theory of volatility index,this paper analyzes and studies the fluctuation trend of grain production in cities in Guanzhong to explore and reveal the trend of agricultural grain production and development in Guanzhong.The grain yield of Guanzhong area and cities was calculated by mathematical regression theory,and the grain yield trend of Guanzhong area in the next 12 years and the urban area in the next 10 years was predicted and calculated.It provides a scientific basis for the benign,scientific and effective development of agricultural production in Guanzhong.The main features and innovations of this paper are mainly reflected in the following three aspects:(1)According to the distribution of water resources in Guanzhong area natural geography,terrain environmental conditions,water supply capacity of water conservancy projects and agricultural utilization and demand of water resources,aiming at the composition and optimal allocation of Guanzhong water resources optimization system,a three-line ten-point water resources distribution network system with the Wei River as the central channel is proposed and discussed.Up to now,there are no other complete allocation network researches on Guanzhong optimal allocation system of water resources.(2)The meaning of agricultural water resources and the theory of regional matching of agricultural water and soil resources are deeply discussed and analyzed in this paper,and the timeliness and spatial analysis of agricultural water-land resources matching are studied.Based on the model of water and soil matching coefficient,this paper calculates and analyzes the water and soil matching relationship of agricultural production in Guanzhong area,which draws a conclusion that is more in line with the actual situation.On the basis of this study,the principal component analysis and principal component regression were used to calculate and analyze the influencing factors of agricultural production in Guanzhong area,and the primary and secondary degree of each factor on agricultural production in Guanzhong was quantitatively analyzed.(3)By using mathematical regression theory to the Guanzhong region and municipal food production yield regression calculation,and the volatility index theory,this paper analyzes the food production fluctuation trend in Guanzhong and its cities,to explore and reveal the agricultural food production and the development trend in Guanzhong.In this paper,the trend of grain production in Guanzhong area in the next 12 years and in each urban city in the next 10 years is predicted and calculated,which provides a scientific basis for the benign,scientific and effective development of agricultural production in Guanzhong.