基于GIS的黄土台塬区土地资源开发利用与生态风险分析

【作者】 马彩虹；

【导师】 任志远；

【作者基本信息】 陕西师范大学 ， 地图学与地理信息系统， 2013， 博士

【摘要】 土地资源集约高效利用与潜力开发是当前普遍关注和亟待解决的热点问题,也是区域生态安全和可持续发展研究的关键和核心问题。陕西黄土台塬区主要分布在关中盆地周边地区,是西北黄土高原台塬的主体部分,也是黄土高原重要的粮食生产基地。随着该区南部河谷盆地经济的快速发展以及北部黄土高原丘陵沟壑区生态问题的日益突出,二者所产生的压力直接辐射和转移到黄土台塬区。因此,陕西黄土高原台塬区面临着高强度开发的态势,潜在巨大的生态风险。本文以陕西省黄土台塬区为主要研究对象,基于GIS和RS支持,收集与处理多源数据,建立Geodatabase数据库对空间数据和属性数据进行一体化管理,从对土地利用的过程和格局分析入手,定量评估了该区域的水土资源压力、农用地集约利用程度和土地资源开发潜力,并对土地生态风险作了分析,提出了差异化的土地资源可持续利用对策与建议。本研究对推动该区域可持续发展、深化人地关系研究具有重要的理论和现实意义。主要结论如下：(1)生态功能性用地比例低且持续减少。1985年耕地面积占78.91%、林地2.04%、草地12.19%、水域0.51%、未利用地0.02%,建设用地6.33%。随着城市化推进,建设用地占用优质土地资源的问题日益严重。1985-2010年,建设用地扩展了32.37%,耕地减少了1.29%、林地面积损失4.59%、草地减少7.18%,水域缩减11.64%。(2)水土资源压力持续增大。尽管1985-2010年土地承载力以年均增长率3.05%的速度提高,但部分区县的人粮关系日趋紧张。2010年,陕西黄土台塬区34个区县中有7个处于严重超载状态,3个为过载状态,6个为临界超载状态。水资源总量不足、水土资源空间分布不均衡。1985-2010年水资源负载指数不断提高,水资源压力也日益严峻。到2010年,约2/3的区县水资源处于“严重超载”状态。(3)农用地集约利用程度不高,经济效益偏低。陕西黄土台塬区优等地占56.50%,但其集约利用程度为中等偏下水平,利用效益低下。质量、利用和经济等级高的区域主要集中分布在一级和二级台塬亚区,三个指标值较低的区域集中分布在渭北三级台塬亚区。(4)受水资源限制,土地资源开发潜力有限。周至和蓝田增产潜力较大,长安区、临潼区、阎良区和凤翔县4个区县的增产潜力中上水平,可达在3-5t/hm2；其它区间增产潜力不大,华县、扶风县、岐山县、三原县、永寿县、泾阳县、礼泉县、乾县和富平县9个区县的增产潜力在2-3t/hm2之间；灞桥区、雁塔区和王益区3个区县的增产潜力在0.4-0.75t/hm2之间,其它16个区县的增产潜力在1-2t/hm2之间。(5)土地生态风险呈增大态势,土地生态风险综合指数由1990年的0.47增大为2010年的0.67。渭北三级台塬亚区最高；秦岭北麓二级台塬亚区、城市地域系统较高；渭北一级台塬和二级台塬区较低。渭北二级台塬亚区和一级台塬亚区土地结构风险较高；城乡交错地带、渭北三级台塬亚区植被退化风险较高；黄土台塬边缘地带以及河谷边坡地带土壤侵蚀风险大；除台塬东北部边缘区很小的范围表现为碳汇之外,其他区域土地碳源效应明显。(6)调整土地利用结构,加强土地生态功能建设。土地潜力利用率低-生态风险高耦合区应提高生态服务功能性用地草地、林地的比例；土地潜力利用率较低-生态风险较高耦合区中,渭北三级台塬亚区和秦岭北麓二级台塬亚区部分可将一部分坡度较大的区域退耕还林(草),咸阳台塬区中部集中连片分布区应侧重于优化农用地种植结构；土地潜力利用率较高-生态风险低耦合区应严格控制建设用地的扩展；土地潜力利用率较高-生态风险较低的耦合区可适当将林地和草地转为耕地用地。主要创新点：(1)提出了土地转移流的概念与模型,籍以表达土地利用变化的矢量属性。传统的土地利用变化测度多基于净值法进行计算,对土地利用变化的数量特征分析较多,但对于土地利用转移的方向性属性重视程度不够,对于挖掘潜藏于复杂转化过程中的一些规律略显不足。(2)将密度制图法运用到土地利用空间集聚特征识别中,在土地利用变化幅度不大的情况下,仍然可以识别出隐藏在土地利用的空间变化特征,弥补了常用叠置分析法对于较小土地变化可视化表达的不足。(3)采用自下而上和自上而下两种思路获取乡镇尺度核算数据,并通过建立Geodatabase数据库实现黄土台塬区土地系统空间数据和属性数据管理与分析。更多还原

【Abstract】 Intensive and efficient use and the development of potentials of regional land resources is one of the hot issues that people are concerned about. And that is also the key and core issue of regional ecological security and sustainable development. Loess Platform region is the major grain production base of Loess Plateau, and is also the important industry and population agglomerations of Loess Plateau in the future. Shaanxi Loess Platform region lies in the Guanzhong Basin. Guanzhong-Tianshui area has been identified by the country as the Third Economic Development Zone of the west. With the rapid development of economic industry as well as the rapid increase of the population pressure, the pressure has been directly radiated and transferred to the loess platform area surrounding Guanzhong. Therefore, loess platform area is facing the exploitation of high strength. There exist potentially enormous ecological risks. In this dissertation the loess plateau area acts as the main research object; based on the support of GIS and RS, multi-source data have been colleted and processed; Geodatabase has been established to conduct integral management of spatial data and attribute data; from the analysis of the process and pattern of land use, the pressure of the soil and water resources of the land system and the intensive utilization degree of agricultural land along with the exploitation potentials of land resources have been quantitatively evaluated. And land ecological risk has been analyzed to put forward countermeasures and advice on the sustainable use of differentiated land resources. The main conclusions are as follows:(1) The proportion of the functional land of ecology is low and continues to decrease. And there is a serious shortage of arable land reserve resources. Arable land occupied78.91%in1985, woodland2.04%, grassland12.19%, water0.51%, the unused land0.02%, the land for construction6.33%. With growing urbanization, the problem that construction land occupies the land resources of high quality is becoming more serious. Within1985-2010, construction land expanded as32.37%, while arable land reduced1.29%, the woodland area4.59%, the grassland7.18%, water area11.64%.(2) Pressure on land and water resources continue to increase. As for the pressure of land, though the land capacity was being increased by3.05%of the average annual growth rate during1985-2010, the relation between people and food in some counties and regions gradually became strained. Up to2010, seven of the34counties and regions in Shaanxi Loess Platform were in the state of severe overloading, three overloading state, six near overloading state. As for water resources pressure, it mainly demonstrated the problems of lack of the total water resources, poor spatial matching of soil and water resources, the prominent structural water shortage, etc. During1985-2010, the load index of water resources continued to increase and water resources pressure was increasingly becoming serious. By2010, approximately2/3of the counties and regions were in the state of serious overloading.(3) Intensive utilization degree of agricultural land is not high, and economic returns are low. The land of high quality of Shaanxi Loess Plateau covers56.50%, yet intensive utilization degree of54.61%of the agricultural land is on the middle and lower level, and the utilization efficiency of51.72%of the agricultural land is low. In space, the basic pattern shows the matching characteristics of equal quality-equal use-equal economy. The areas with the same quality, the same utilization, the same economy mainly distribute in the primary and secondary platform sub-regions, the areas with the value lower of the three indicators mainly distribute in the sub-areas of platform of Level three in Weibei.(4) Owing to water restrictions, most of the counties and regions exploitation potential of land resources is limited and the difference between the counties and regions is much larger. Among all the counties and regions, the production potential of the two counties, Zhouzhi County and Lantian County can reach the maximum potential of climate; in the four counties of Chang’an District, Lintong District, Yanliang District and Fengxiang County the production potential is3.0-5.0t/hm2; in the nine counties of Hua county, Fufeng County, Qishan County, Sanyuan County, Yongshou, Jingyang, Liquan dry county and Fuping County, the production potential is2.0-3.0t/hm2; in the three counties and regions of Baqiao District, Yanta District and Wangyi District the production potential is0.4-0.75t/hm2, the production potential of the other16counties are1.0-2.0t/hm2.(5) The land ecological risk indicates a tendency of increase. It increased from0.47in1990to0.67in2010. In space it demonstrates Weibei loess platform of Level3is the highest. Qinling northern hillfoot sub-regions of Level2and urban region system are higher; Weibei loess platform of Level1and2is lower. However, types of risk sources and intensity of different regions of space are quite different. The risk of land structure of Weibei platform sub-areas of Level2and1and is higher; in the crossing zones of urban and rural pastoral areas, including Weibei loess platform sub-areas of Level3the risk of vegetation degradation is higher; in the loess platform and valley slope zones there is a high risk of soil erosion; except the fact that it indicates carbon sink within the very small range of the edge zone of north-east of loess platform, the carbon source effect of land of the other areas is obvious.(6) The land utilization structure is to be adjusted; the construction for ecological functions of land is to be strengthened; the control strategies of differentiated sustainable land utilization are to be adopted. land utilization and ecological coupling state of loess platform can be divided into four types, among of them, the proportion of woodland and the ecological service function of land for grass in those typed areas with low potential of land utilization and a high ecological risk should be raised; in those typed areas with low potential of land utilization and a high ecological risk, as for Weibei loess platform sub-areas of Level3and Qinling northern hillfoot sub-areas of Level2, part of the steep slope area of it can be used for returning farmland to forest; more emphasis should be placed on optimizing the planting structure of agricultural land in the contiguous distribution areas of central Xianyang loess platform; there should be a strict control of the expansion of construction land in the coupling regions with higher utilization rate of the potential of land and a low ecological risk; in the coupling regions with higher utilization rate of the potential of land and a lower ecological risk, part of woodland and grassland can be changed into arable land.Major creativity:(1) The concept of land transfer flow and its model has been put forward; the reflection of the vector properties of land change has been highlighted.(2) Density mapping method has been applied in the clustering feature recognition of land utilization space so that it has made up for the shortcomings of visualization of smaller land change by the commonly used method of overlay analysis.(3) Township-scale accounting data have been abtained via bottom-up and top-down methods. And the management and analysis of space data of land system and attribute data of the loess tableland have been carried out by establishing Geodatabase database.更多还原