Utilization Assessment And Equilibrium Optimization Control Of Agricultural Water And Land Resources

Agricultural water and land resources are the material basis of human production and life,its uneven distribution and unreasonable utilization seriously threaten regional development and food security.Based on the theory construction,the study firstly analyzed and evaluated the matching characteristics of agricultural water and land resources in Ningxia by several spatial analysis methods,and then answered the key question of how factors of water & land resources utilization impact on agricultural output in Ningxia.Coupling coordination model was selected to comprehensively assess the coupling and coordinate degree of agricultural water & land resource-agriculture & rural economy-ecological environment.Finally,typical irrigation district was chosen to establish an equilibrium optimization allocation model of agricultural water & land resources.The study aimed at providing theoretical and technical support for the management of agricultural water & land resources in Ningxia.The main conclusions are as follows:(1)By refining the basic theories of equilibrium optimization control of agricultural water & land resources,we raised its concept and connotation.The cores points of the connotation include "water and land resource matching","big system coordination" and "space-time balance".The basic principles,decision-making mechanism and main technical paths for achieving equilibrium optimization of agricultural water & land resources were also illustrated.(2)A relatively better degree of spatial balance was shown between effective irrigated area(EIA)-agricultural irrigation water(AIW)rather than farmland area(FA)-agricultural irrigation water(AIW).During 2007 to 2017,the matching degree of agricultural water and land resources in Ningxia constantly improved,while a greater variability in the distribution of agricultural water resources was shown in areas with irrigating conditions.According to the spatial mismatch index,counties with sufficient irrigation were mainly distributed in central-northern Ningxia,while areas where AIW is scarce were mainly distributed in the south and east part of Ningxia.The sensitivity of agricultural irrigation water volume to agricultural land resources obviously increased from 2007 to 2017.Besides,counties with higher sensitivity of AIW to FA or EIA showed a trend of moving northwards.It can be also concluded that the method calculated by unit area is not applicable for areas where natural conditions are in widely differ in the interior.(3)The results of LMDI model showed that the efficiency of agricultural water use was the most important factor affecting the changes in agricultural output value of Ningxia.So improving the efficiency of agricultural water use remains the primary strategy for development of agricultural economy.From the perspective of different crops,the effect of grain production structure was the largest positive driving force for grain output growth in Ningxia during 2007 to 2017,indicating that the direction of grain crop structure adjustment in Ningxia during the study period is reasonable.Take no account of different crops,the effect of cultivate-land use intensive degree and cultivated land use breadth were the main increment and decrement effect of total grain output,respectively.The key measures for the future development of grain production should be to increase the grain yield and increase the multiple cropping index.(4)Agricultural water & land resource system,agriculture & rural economy system and ecological environment system are closely related,with restrictions and connections between subsystems.The comprehensive evaluation indexes of each subsystem in Ningxia shown an obvious increasing trend during 2007 to 2017.The big agriculture system also achieved good-quality development from "high coupling-low coordination" to "high coupling-high coordination" during the study period.(5)Helan irrigation district was taken as an example for the establishment of an equilibrium optimization allocation model of agricultural water & land resources.It is a multi-objective model aiming at balancing water and land resources,balancing irrigation water spatially and temporally,and optimizing ecological water level.Optimization configuration model and groundwater simulation model were combined to calculate.Consequently,the study obtained the optimal allocation results of irrigation water resources in the Helan irrigation area in the planned year,so that achieve the balanced allocation of irrigation water resources spatial-temporally and effectively control the groundwater level.