Study On The Agriculture Water-saving Potential Of Irrigation District Based On Water Footprint Theory

Agriculture is a largest part of water consumption, the efficient utilization of waterresources is the necessary requirement of agricultural development. The research ofagricultural water-saving potential is significant for developing water-saving agriculture inour country, due to agriculture has the largest water-saving potential. However, up to nowagricultural water-saving potential is still no unified understanding, due to the significantdifference exists in its concept and connotation. As a result, its calculation results are notcomparable.In this paper the water footprint theory are used to explore the true value of agriculturalwater-saving potential and built the framework system and calculation method of agriculturalwater-saving potential, which are applied to the Hetao irrigation district. The main researchresults are as follows:(1) The theoretical framework and calculation model of agricultural water-savingpotential are established. The theory framework of agricultural water-saving potentialincludes four levels: essence, kernel, outer core and environment. The essence is crop waterrequirement as the logical starting point; kernel is seven part of agriculture water savingpotential research in irrigation district; outer core is factors played an indirect effect on thecalculation process and structure of agriculture water-saving potential; and environment areincluding4parts: the culture environment, institutional environment, technology environmentand economic environment. The calculation model of agricultural water-saving potential isestablished and its boundary conditions are presented. Agricultural water-saving potential isthe subtraction between the agricultural production water footprint and the control standard ofagricultural production water footprint. The boundary conditions are given as well.(2) The threshold value interval of the control standard of agricultural production waterfootprint is put forward, and the calculation process of agricultural water-saving potential isgiven. The threshold value interval of agricultural production water footprint control standardis [Crops economic water requirement, agricultural economic water consumption]. Thecalculation process of agricultural water saving potential is: fistly, the agricultural economic water consumption is determined with crop water requirement as the logical starting point andagricultural production in irrigation district as a starting point. Then, crops economic waterrequirement are calculated with crop water requirement as logical starting point combiningwith the water production function. And then, the blue, green, and grey water footprint ofagricultural production are computed with the irrigation, precipitation and the negative effectsof agricultural production, the water footprint of agricultural production are calculated as well.Finally, the control standard of agricultural production water footprint are computed withcrops economic water requirement and agricultural economic water consumption, theagriculture water saving potential of irrigation district are calculated.(3) Agricultural production water footprint and the systemic evolution law of agriculturalproduction water footprint in nearly50years are analyzed and calculated. The green and bluewater footprint of agricultural production was calculated under different drought level in thecrops growth period and the grey water footprint of agricultural production was evaluated.The water footprint of agricultural production was calculated under the different drought leveland the condition of irrigation in year of2015,2020and2030. The synergy evolvementalienation regularity in nearly50years was studied by using coordination theory in the systemof agricultural production water footprint. The results show that there was a big change ofvalue of coordination degree happened in year of2004, and the alienation characteristic ofsystem was significantly.(4) The reasonable planting structure and threshold value interval of agriculturalproduction water footprint control standard were put forward, and the farming available waterresources were calculated. The synergy evolvement alienation regularity in nearly50yearswas studied in the system of planting system by using coordination theory. There existed asignificant change of coordination degree happened in year of2004, and the alienationcharacteristic of system was significantly. The reasonable proportion of crops plantingthreshold interval were put forward: grain crop was (47.82%,62.66%) and commercial cropwas (24.64%,43.49%). In the threshold interval, water and soil resources matched morereasonable, the environment pressure is low, and the system is in highly coordinated orcoordination level. Under the guarantee food security, the control standard threshold valueinterval of agriculture water footprint was put forward, and the planting available waterresources were calculated.(5) Agricultural water-saving potential were calculated in3scene modes, which were theguarantee food security, the reasonable planting structure and water resource constraint, andin2005-2008. Agricultural water-saving potential is not a fixed value, but an interval value.In general, when the greater the proportion of water saving irrigation area were, the smaller the upper and lower limit of threshold value interval in agricultural water-saving potential.The lower limit of threshold value interval were achievable water-saving potential, whichwere the reality of water-saving potential realized by adopting engineering water-saving andagronomic water-saving measures. The upper limits of threshold value interval were the idealvalues of agricultural water-saving potential which could not reach. It found insufficient watersupply coefficients should be greater than0.8when all efficient water-saving irrigationdistricts.(6) Environmental factors were numerous and the changes were differences. Theinfluences on agricultural water saving potential were analyzed by selected the moderatechanges of environmental factors which were agricultural policy and social economicdevelopment level. In the factors of agricultural policy, crops planting area, total grain outputand farmers’ net income were negative associated with agricultural water-saving potential,agricultural production water footprint was a positive associated with agriculturalwater-saving potential. The evaluation index system of social economic development level,which included4levels and25indicators in the irrigation area, were founded. Socialeconomic development level were evaluated using10indexes in Hetao irrigation district, andit from year of2005to2008was-0.473,-0.390,-0.277and-0.098, respectively. In Hetaoirrigation district social economic development level were the low level in2005-2007andgeneral level in2008. Social economic development level was negative correlation toagricultural water-saving potential.