Evaluation And Promotion Of Green Efficiency Of Agricultural Water In The Yellow River Basin

The Yellow River is the second longest river in China,and the mother river of the Chinese nation,with a runoff of about 2% of the country carrying 9% of the population and 15% of the arable land area.As an important food base and ecological function area in China,the agricultural water resources of the Yellow River basin is related to national food security and ecological security.However,with the rapid economic development and population growth in the Yellow River Basin,the scale of water resources development and utilization along the Yellow River Basin has been expanding.And the special water resources situation in the Yellow River Basin has made the contradiction between supply and demand of agricultural water resources and the fragile ecological environment in the Yellow River Basin increasingly prominent,and has posed a great challenge to the agricultural activities in the basin,mainly irrigation.Currently,under the requirement of ecological protection and high quality development strategy of Yellow River Basin,the new idea of agricultural water resources management in Yellow River should be changed to high quality green development in the context of ecological civilization construction in the basin.The development of the basin requires to say goodbye to the past crude development model that overly focuses on quantity,scale,speed and one-sided pursuit of economic efficiency growth,and instead pursue the overall improvement of quality and efficiency.Therefore,under the constraint of resources and environment and the demand of economic-social-ecological synergistic development,how to improve the green efficiency of agricultural water(GEAW)becomes an important issue to ensure food security,improve ecological environment and meet the demand of sustainable agricultural development in the Yellow River Basin.This study focuses on the evaluation and improvement path of GEAW in the Yellow River Basin,and focuses on four core questions: First,what is the level of GEAW in the Yellow River Basin? Second,what are the regional differences and non-equilibrium characteristics of GEAW in the Yellow River Basin in terms of spatial and temporal changes? Third,what are the key influencing factors and spatial effects of GEAW improvement in the Yellow River Basin? Fourth,what are the future trends of GEAW in the Yellow River Basin under different scenarios? How to design a scientific and reasonable path to improve GEAW? This study combines the research ideas of geography and economics,and follows the logic of‘phenomenon-structure-process-mechanism-influencing factor-improvement path’.Based on the definition of relevant concepts,literature review,theoretical review and analysis,and the comprehensive use of descriptive statistics,spatial statistical analysis,econometric models,BP neural networks and other methods.This study evaluates the GEAW,water saving potential,and the improvement path of GEAW in the Yellow River Basin from the perspective of green development,based on the panel data of 87 prefecture-level cities in the Yellow River Basin from 2000 to 2019,respectively,from multiple perspectives at the basin,provincial and municipal levels.Based on the panel data of 87 prefectural-level municipalities in the Yellow River Basin for the year 2000 to 2019,we have evaluated the dynamic changes of GEAW,water saving potential and inter-regional differences in the Yellow River Basin under the perspective of green development.Analyzed the spatial and temporal evolution,clustering and convergence characteristics of GEAW in the Yellow River Basin,and constructed a theoretical analysis framework to examine the key influencing factors and their spatial effects on the improvement of GEAW in the Yellow River Basin.Further,based on the results of the identification of key factors influencing GEAW improvement,the BP neural network method was used to dynamically simulate the future changes of GEAW in the Yellow River basin under different scenarios and identify the optimal path for GEAW improvement.Finally,based on the above empirical findings,we propose corresponding policy inspirations based on the reality of the Yellow River basin.The main research conclusions obtained are as follows.First,the GEAW in the Yellow River Basin shows a stable upward trend,but there are obvious differences between regions.The GEAW has increased from 0.43 in 2000 to 0.81 in2019,which is still some distance away from the effective frontier surface,and there is still room for improvement in GEAW.At the provincial level,the average value of GEAW in Shaanxi is the highest,and the average value of efficiency in Ningxia is the lowest.At the city level,Guyuan,Linxia and Wuhai have the highest average GEAW.The agricultural water saving potential shows a steady decline from 467 million cubic meters in 2000 to 136 million cubic meters,with large differences in water saving potential between different regions.At the provincial level,Ningxia has the highest water saving potential and Shanxi has the lowest;at the city level,Haixi,Yinchuan and Zhongwei have the highest agricultural water saving potential in 2019.The Dagum coefficient of GEAW has a clear downward trend,indicating that the gap in GEAW between regions has been narrowing and there is a convergence trend.Second,the GEAW has significant spatial clustering and dependence characteristics,and the center of gravity of efficiency fluctuates to the northwest,but there is still polarization and spatial imbalance as a whole.The GEAW shows the distribution characteristics of "two peaks standing side by side" and left trailing,and the GEAW of each region shows a stable trend of improvement over time,and there are two levels of differentiation and spatial imbalance.The distribution of areas with higher GEAW is more stable.While those with lower GEAW are gradually growing,but there are still obvious gaps between areas,and the distribution trend of double peaks will persist and show a convergence trend.The GEAW shows a significant spatial autocorrelation,there are positive clustering and dependence characteristics.The geospatial pattern is an important factor affecting the GEAW.The spatial clustering of GEAW shows a spatial pattern of low-low clustering areas mainly in Gansu and Qinghai in the upper reaches,high-high clustering areas mainly in Shaanxi,Shandong and Henan in the middle and lower reaches,and high-low dispersion and low-high dispersion areas in the periphery,with the distribution pattern remaining basically stable in general.The spatial clustering pattern of GEAW has changed significantly,and the center of gravity of GEAW has gradually shifted to the northwest,from Weinan to Linfen,gradually showing a significant "southeast-northwest" spatial distribution pattern.Third,there are significant convergence characteristics of GEAW,and regional convergence is an inevitable trend in the development of GEAW.There are differences in the influence of related variables on the significance of convergence.The agricultural water use efficiency in the Yellow River basin and the upper,middle and lower reaches of the Yellow River basin all have alpha convergence,and the GEAW of each city and region converges toward its own equilibrium steady state level.The degree of change of alpha convergence coefficient is downstream > upstream > midstream.The development of GEAW in the Yellow River basin and the upstream,middle and downstream regions shows absolute β convergence,and the speed of convergence is upstream > middlestream > downstream.Under the consideration of regional differences,there is a significant trend of conditional β convergence in GEAW as a whole and in the upstream,middle and downstream regions,and the rate of convergence decreases compared with absolute β convergence.The rate of convergence still shows upstream > midstream > downstream.In addition.Factors such as resource endowment,socio-economic development and technological progress play an important role in the convergence process of GEAW,but they vary in different regions and periods.Based on the club convergence results of the cluster classification,there is a significant spatial club convergence trend in the Yellow River basin,and the convergence rate shows a low efficiency zone > medium efficiency zone > high efficiency zone.The evolution of GEAW is influenced by regional conditions.Areas with low efficiency levels of GEAW are more likely to accumulate,resulting in a tendency for the "low efficiency club" to expand.Fourth,there is a significant spatial spillover effect on GEAW in the Yellow River basin,and there is significant variability in the influence and spatial effect of various factors on GEAW.From the perspective of the Yellow River basin as a whole,rural per capita disposable income and effective irrigation level have significant positive effects on GEAW.Labor transfer,mechanization input and water use structure have significant negative effects on GEAW.At the same time,GEAW has a significant spatial spillover effect,which makes the improvement of local GEAW have a significant positive impact on the GEAW of neighboring areas.From the sub-basin results,the spatial spillover effect is still significant,and there are differences in the degree and significance of the influence of each influencing factor on GEAW in the three major sub-regions of upstream,middle and downstream.In the upstream area,the average annual rainfall,labor force transfer,agricultural mechanization input intensity and water use structure have significant negative effects on GEAW,while the effects of rural per capita disposable income and effective irrigation level on agricultural water use efficiency are significantly positive.In the midstream area,the effects of urbanization level and effective irrigation level on GEAW are significantly positive,while the effects of water use structure on GEAW are significantly negative.In the downstream area,the effects of labor force transfer and urbanization level on GEAW are significantly positive.The impact of labor force transfer and urbanization level on GEAW is significantly positive,while the impact of agricultural mechanization input intensity,water use structure and effective irrigation level on a GEAW is significantly negative.The decomposition of spatial effects shows that labor transfer and effective irrigation level have significant positive indirect effects on GEAW in the Yellow River basin.The average annual rainfall,labor transfer and effective irrigation level in the upstream area have significant spatial spillover effects,the mechanization level in the midstream area has significant spatial spillover effects,and the rural per capita disposable income,labor transfer and water use structure in the downstream area have significant Spatial spillover effect.Fifth,the predicted value of GEAW in the Yellow River basin is improved under different scenarios.The optimal improvement paths of GEAW in the Yellow River basin and in the upper,middle and lower reaches are differentiated.The predicted value of GEAW in the Yellow River Basin is improved under different scenarios.The GEAW using the priority development scenario of rural per capita disposable income is the highest,with an increase of21.68% compared with the GEAW in 2020.The predicted GEAW of the three major subregions in the upper,middle and lower reaches of the Yellow River basin were improved under different scenarios,and the improvement of GEAW in each region was midstream >downstream > upstream.In particular.The GEAW in the upstream area is the highest under the baseline development scenario,with an increase of 24.68% compared with the GEAW of0.69 in 2020.The GEAW in the downstream region is the highest,with an increase of 27.77%compared with the GEAW of 1.08 in 2020.The predicted values of GEAW in the Yellow River basin and in the upper,middle and lower reaches are different under different development scenarios and different time periods,and each region should adopt different development strategies in different periods.Based on the above research findings,the following policy revelations are proposed.First,to clarify the key areas of agricultural water conservation and efficiency in the Yellow River Basin.Second,to construct a spatial governance system for agricultural water efficiency in the Yellow River Basin.Third,to promote the growth of farmers’ income in various ways.Fourth,to develop high-efficiency water-saving irrigation.Fifth,to systematically identify the differences in the paths of GEAW improvement in each region.