Research On Zoning Of Agricultural Water And Land Resources Utilization And Their Matching Characteristics In Arid Areas Of Northwest Of China

Water and land resources (WLR) are two of the most vital resources in agricultural andfood production systems. The situation of WLR is tied up with security and stability of foodproduction in China. Recently, the conflict between demands of WLR due to the populationgrowth and economic development and its inherent characteristics with scarcity and limitationis increasing, so that WLR management has been paid more attention by scientists，especiallyin arid areas where issues related to WLR utilization are more obvious.The scope of arid areas in Northwest China (NW) is vast. It has abundant resources oflight, solar and land, and thus is an important reserve base of food production in China.However, the landscape is characterized by a unique morphological complexity consisting ofmountains, basins, plain, deserts, and rivers in NW. Moreover, regional differentiationcharacteristics including geographical and socio-economic differences are obvious.Correspondingly, identifying and understanding geographical characteristics and theconditions of agricultural water and land resources utilization (AWLRU) is the preconditionfor the goal of achieving the effective and sustainable utilization of AWLR. It can contributeto formulating the more effective measures and planning for AWLR management.Based on the current data and technology/tools, this study identified dry/wet climaticzones by applying theories and methods in the fields of geography, climatology and statistics,and the scope of arid areas of NW was delimited. Next, we developed a general frameworkfor designing and selecting indicators of AWLRU zoning, and then established the zoningscheme of AWLRU in arid areas of NW. Then, a systematic method was advanced to help tounderstand the matching and scarcity characteristics of AWLR. Based on it, we analyzed the matching situation of AWLR in arid areas of NW, and further discussed measures forachieving reasonable matching situation of AWLR. The final goal of this study was to providethe theoretical basis for proposing and establishing the effective and sustainable utilizationmode of ALWR. The following main conclusions can be drawn:(1) This study delimited the scope of arid areas of NW.In view of the shortcoming and disagreement on the scope of arid areas of NW inprevious studies, we identified the dry/wet climatic characteristics by applying themulti-variable statistical analysis based on the last30years (1981–2010) in this study.Meanwhile, it made a further definition and explanation on the concept of arid areas and itstypes. Based on this, we defined the scope of arid areas of NW, and analyzed differencesbetween the current and traditional methods. Results showed that major terrain features wereimportant components of boundaries among different climate regions. It indicated thatdivisional boundaries appeared to be greatly influenced by natural features or barriersbetween regions.Meanwhile, the concept of arid areas was defined as water-deficient areas induced byresource scarcity and characterized by climatological drought. Its types included arid,semi-arid and dry sub-humid regions. The scope of arid areas of NW is: the whole area of fourprovinces, including Xinjiang, Qinghai, Gansu and Ningxia, and regions of Guanzhong Plain,north Shaanxi and the Inner Mongolia Plateau. The total area is3.69×106km2, accounting for38.4%of China.(2) This study developed a general framework for designing and selectingindicators of AWLRU zoning.Based on the understanding of related theories and meaning of AWLRU, we designed theframework including five attributes or layers in AWLRU system by combining thesupply–demand (SD) theory with the DPSIR (Driver–Pressure–State–Impact–Response)model. They are supply capacity, demand level, exploration and utilization level, utilizationstatus and limiting factors, respectively. Bayan Nur of Inner Mongolia was selected as thecase study to understand the application of the proposed framework and confirm itsreasonability. Results indicated that divisions of AWLRU had obvious differences dependingon the effects of the Yellow River and Yinshan Mountains. Divisions were drawn clearly fromwest to east and from south to north. It indicated that the AWLRU zoning was bound up with water supply. The case study demonstrated the practicality and reasonability of the proposedframework. The proposed framework could guide the establishment of indicators andidentification of characteristics of AWLR zoning.(3) This study identified the zoning characteristics of AWLRU in arid areas of NW.Based on the principles of selecting indicators, this paper took cities as basic units todefine values of zoning indicators. By combining the Principle Components Analysis (PCA)and Cluster Analysis (CA), the zoning scheme of AWLRU in arid areas of NW wasestablished. Meanwhile, according to investigation and comprehensive analysis, weunderstood and compared the characteristics of AWLRU, and summed up the basic laws on itsspatial pattern and utilization directions. Results indicated that four types of divisions ofAWLRU were identified: irrigated farming regions, dry-farming agricultural regions with thecomprehensive characteristics of farming and pasture, the industrial and mining districts withnon-advantages for developing agriculture, and mountains and hills areas depending onforestry and livestock farming but also including agriculture. Among zoning indicators, therate of irrigated arable and fertilizer consumption per arable land were two most importantfactors affecting the development mode, direction and outputs of AWLR.Results also indicated that irrigated farming regions mainly distributed in basins andplains where water supply is sufficient and land is fertile, whereas agriculture was developedtowards the direction of forestry and livestock farming in regions with mountains, hills andravines due to the low availability of land resources. Under the condition of water scarcity, thearable region was developed as the dry-farming cultivated mode. In regions that land resourceis poor but mineral resources are abundance, regional economic development was dominatedby industry and mineral industry due to the effects of comparative advantages. It furtherindicated that location advantage, resource advantage and geographical differentiation playedan important role in the process of development and utilization of AWLR.(4) The matching and scarcity characteristics of ALWR were measured andevaluated. Measures and ways for achieving the reasonable matching situation of AWLRwere put forwards in this study.From the view of generalized agricultural water resources, we analyzed the spatialmatching characteristics of AWLR and relationship between the components of agricultural water resources and matching index of AWLR. By combining resource equivalency analysis,we established an evaluation method measuring the severity of resources shortage. Resultsindicated that the matching index of AWLR was high in irrigated farming regions with aridclimate, and it is low in dry-farming regions characterized by rain-fed agriculture andlivestock farming. Besides, the higher the ratio of blue and green water is, the higher thematching index of AWLR is. Thereinto, there was a positive correlation between blue waterand matching index of AWLR. When green water resource is about350mm, the matchingindex of AWLR is lowest.There is a severe shortage of cultivated land in semi-arid climate region dominated bydry farming, dry sub-humid region with rich precipitation and regions with sufficient meltwater resources. The matching index of AWLR and equivalent coefficient of AWLR werehigher in regions in extremely arid zone and arid zone, which is severe water shortage region.It indicated that the distribution of AWLR was extremely uneven. It presented seriousseparation between forming region and water-consumption region. Based on it, measures andways for achieving the reasonable matching situation of AWLR were put forwards.