| Water is the basis of grain production.At present,the shortage of water resources has become a prominent problem restricting food security and economic development.Along with the northward movement of grain production center,the water-soil-grain allocation is seriously imbalanced between the South and the North,between non-arid areas and arid areas.Over-exploitation of water resources in North and Northwest of China is especially serious.Some experts say that lack of water resources will become the biggest threat to Chinese agriculture in future.Shandong is a major province of grain production,whose area and output of grain sown are the third,and plays a very important role in ensuring food security of China.However,Shandong is also a province of water shortage.The average total amount of water resources for many years is less than one sixth of the national average level.It belongs to a serious water shortage area with per capita occupancy less than 500m~3.Besides,serious imbalances,crowding-out,pollution,coexistence of shortage and waste are all evident in Shandong.Agricultural water use is a major water user,of which grain irrigation water accounts for a large proportion.Especially in Shandong,the grain production structure mainly consisting of winter wheat and summer maize has a high dependence on irrigation water.The severe situation of water resources and the important task of ensuring food security make water resources in a dilemma.Because water resources cannot be relieved by import substitution like other resources,it has important practical significance and academic value taking Shandong as an example to study the water allocation for grain production.This paper is mainly based on the theory of resource allocation,marginal productivity,production frontier and public goods.The research interval is from 2001 to 2016.The research perspective is the whole province and its 17 cities.The research framework was put forwards based on the analysis of the present situation and problems.The efficiency and space-time characteristics of water allocation in grain production were comprehensively analyzed.The characteristics and coordination mechanism of water allocation for grain production from the perspective of regional differences and industrial development were studied.On the basis of forecasting supply and demand relationship of water resources in grain production,the optimal allocation strategy of water resources for grain production was put forward.The main research contents and conclusions are as follows:(1)The allocation efficiency of water resources in grain production was measured and the potential of water saving in grain production was estimated.The efficiency of water allocation in grain production is lower than that in grain production,which indicates that water resources allocation needs to be optimized more than that of comprehensive factor allocation.The average efficiency of water allocation for grain production is 0.59.The efficiency of water allocation for grain production is the highest in northern Shandong,but its efficiency of water resources allocation is almost the lowest.The potential of water saving for grain production based on improved allocation efficiency is huge.The average value of water saving potential for the whole province is 3.089 billion cubic meters.The potential of water saving in northern Shandong is the largest,and the share of water saving in total water consumption reaches 36.52%.The water-soil-grain mismatch in northern Shandong shows the typical characteristics of both shortage and waste of water resources in this area.(2)The reserach revealed the convergence and spatial characteristics of water resources allocation efficiency in grain production.The changing trend of water resources allocation efficiency disparity of grain production depends on its own conditions.It is not that each city converges to the same steady-state value,but converges to its own steady-state level.The difference of water resources allocation efficiency among regions does not disappear,and finally reaches a stable state.The efficiency of water allocation for grain production in Shandong shows a positive spatial autocorrelation,and the spatial Moran index has experienced a process of increasing first and then decreasing.The local spatial autocorrelation Lisa chart shows that the efficiency of water allocation for grain production in Shandong presents the features of block distribution on the whole,but also fragmentation on the part.The total spillover effect is mainly affected by indirect spillover,and the two directions are identical.Through the analysis of spatial effect,it is shown that spatial characteristics are important factors affecting the allocation of water resources,which should be taken into account in the optimal allocation of water resources for grain production to achieve inter-regional optimization.(3)This research quantitatively explored the constraints and matches of water resources on grain production and the characteristics of regional differences.Based on the water resources growth drag model,it was found that the growth rate of grain output value is 0.022%slower than that of the previous year due to the shortage of water resources.Water resources have different restrictions on grain production in different regions.The grain production concentrated areas in North and Southwest Shandong are greatly restricted by water resources,especially in Dezhou and Liaocheng.The comprehensive matching model of water,soil and grain was constructed,and it was found that the factors of water and soil resources in Shandong grain production were extremely mismatched.Among the 13 major grain producing provinces in China,the comprehensive matching degree of water,soil and grain in Shandong was only higher than that in Henan,which was 26.6%of the national average level.In general,the coefficient of water,soil and grain matching of eastern part is superior to the western part,the southern part is superior to the nothern part,in the hilly area is better than that in the plain.Regional water resources abundance and shortage,soil reclamation efficiency,grain production structure and water use efficiency are important factors affecting the matching of water and soil resources in grain production.(4)The effects of benefit gap,planting structure and policy factors on the allocation of water resources in inter-industry grain production were discussed.The benefit gap between industries and the growth of domestic water demand promote the non-agriculturalization of water resources,and the amount and proportion of agricultural water were declining year by year.The comprehensive benefit of single cropping mode of wheat and maize is low,which promoted the water resources to escape from grain production.The cropping structure of grain crops affects the water demand for grain production.The single cropping pattern of winter wheat and summer maize has a high dependence on irrigation water.In recent years,the adjustment of cropping structure of grain crops has been promoting the development of water saving.Through game analysis,it is found that properly raising water price and formulating scientific incentive policies for water resources management are conducive to promote farmers to adopt water-saving technologies and saving irrigation water resources.(5)The optimal allocation strategy of water resources for grain production was put forward.According to the grey relational degree prediction,the water resources security thresholds of grain production in 2020 are 9.669 billion cubic meters.And there are 1.069billion cubic meters of irrigation water gap in 2020.It is urgent to optimize the allocation of water resources.Based on the coordinated development of economic benefit,social benefit and ecological benefit,the optimal allocation strategy of water resources for grain production is put forward.By constructing a multi-objective fuzzy calculation model,the water resources allocation schemes for 2020 and the grain production and planting structure adjustment schemes are clarified.On this basis,the optimal allocation strategy is put forward from three levels:interregional,inter-industry and intra-industry,in order to provide decision-making reference for government departments.Based on the problems of grain production and water resources allocation,this study systematically quantifies the utilization of water resources in grain production in Shandong,constructs an analytical framework for water resources allocation in grain production,reveals the temporal and spatial evolution characteristics of water resources in grain production from the angles of allocation efficiency,interregional and inter-industrial allocation,provides a new perspective for the study of water resources in grain production,and enriches water resources.The theory of source allocation and carrying capacity provides decision-making reference for Shandong to formulate water resources allocation scheme for grain production,and helps to realize sustainable development of grain production and water resources. |
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