Study On The Change Characteristics And Driving Mechanism Of Agricultural Water Resources Stress In The Yellow River Basin

The Yellow River basin as a important grain production base in China,the imbalance of water resources supply and demand is increasingly prominent.In 2019,the ecological conservation and high-quality development of the Yellow River Basin(YB Conservation and Development)was launched,which set higher requirements for the quality of agricultural production and water resources conservation.Therefore,it is necessary to study the relationship between supply and demand of water for grain production,and analyze the driving factors of agricultural irrigation water resources stress,so as to provide a theoretical basis for the formulation of high-quality agricultural development policies in the Yellow River Basin.This study takes 49 prefecture-level cities in the Yellow River Basin as research objects.The gravity center model and spatial autocorrelation analysis were used to explore the temporal and spatial changes of agricultural irrigation water resources stress and grain production distribution pattern,and the logarithmic mean divisia index(LMDI)technique is used to analyze the driving factors of agricultural irrigation water resources stress change.This study reached the following key conclusions:(1)Explored the distribution pattern of water resources and grain production in the Yellow River BasinWater resources are relatively abundant in the southwest of the Yellow River Basin,and show a trend of increasing in the west and decreasing in the southeast.There was a mismatch between the spatial distribution of irrigation water consumption and water resources,with high stress on agricultural irrigation water resources in many areas,especially in Ningxia,middle of Shaanxi,Henan and Inner Mongolia within the Yellow River Basin,and the areas with low stress of agricultural irrigation water resources are mainly concentrated in the west of the Yellow River Basin.Grain production grew rapidly during the study period,with the total output in 2019 about 1.4 times that of2000 and the economic output of grain about 4.2 times,and grain capacity is greater in the eastern part of the basin.The cultivated land area changed little in the study period,and it’s distribution pattern was similar to grain yield.(2)Reveals the gravity shifting process of agricultural water resources stress and grain production in the Yellow River BasinThe gravity center of agricultural irrigation water resources stress is located in the northwest direction of the geometric center of the Yellow River Basin,and the deviation degree is greater in the north-south direction.During 2000-2019,the gravity center of agricultural irrigation water resources stress shifted to the southeast.The grain production gravity center is located in the southeast of the geometric center of the Yellow River Basin,and the deviation degree is greater in the east-west direction.During the study period,the center of gravity of grain production fluctuated in the eastwest direction and showed a clear trend of moving north in the south-north direction,indicating that the southern part of the Yellow River basin was still the high-yield area of grain production,but the advantage of grain production gradually tilted to the northern part over the years.(3)Analyzed the spatial autocorrelation between water resources stress and grain production for agricultural irrigation in the Yellow River BasinIn the whole basin,there was an obvious spatial positive correlation of agricultural irrigation water resources pressure,showing a spatial aggregation phenomenon,and the interannual fluctuation range of the global Moreland index was decreasing,so the spatial correlation tended to be stable.Grain production also showed spatial aggregation,but the global Moreland index was relatively small and trend downward.It’s indicates that grain production in the low-yield regions in the early stage of the study has developed more rapidly,especially in Yulin,Ordos and other northern regions,which reduces the spatial difference in grain production between the northern and southern regions.From the local analysis,the aggregation forms of food yield and water resources pressure for agricultural irrigation include low-low aggregation,low-high aggregation and high-high aggregation.(4)Explored the driving factors of irrigation water resources stress and its effects in the Yellow River BasinThe driving effects of water use intensity,crop production efficiency and water resource endowment are more obvious than other factors.From 2000 to 2019,the water use intensity factor played a very important driving role in reducing water resources stress,and the contribution rate of grain crops water use intensity factor decreased gradually from upstream to downstream,but it was the opposite for cash crops.Production efficiency factors play a positive driving role in the increase of agricultural irrigation water resources stress,because the improvement of crop yield per unit area requires irrigation support.In the upper and middle reaches of the Yellow River Basin,the driving effect of grain crops was dominant,while in the lower reaches,the driving contribution of cash crops was slightly greater.The influence of water resource endowment factors varies greatly between time and space.In terms of time,2000-2003,2009-2011 and 2015-2019 showed a significant driving effect of stress reduction,while other years showed a driving effect of stress increase.Spatially,the region with significant increase of agricultural irrigation water resources stress during the study period showed a very strong positive driving effect,while the region with significant decrease of agricultural irrigation water resources stress showed a negative driving effect,which was an important reason for the gravity center of agricultural irrigation water resources stress to move southeast.