【作者】 马廷刚；

【导师】 常庆瑞；

【作者基本信息】 西北农林科技大学 ， 土地资源与空间信息技术， 2011， 硕士

【摘要】 本研究以关中平原-陕西省户县为研究对象,分析了1985-2009年土地利用覆被变化,并利用地形位指数和土地利用程度综合指数,探讨了陕西省户县土地利用格局的空间分布,并分析了该区地形梯度上的土地利用程度。并且在ArcGIS等软件的支持下,结合地统计学,分析了户县各种土壤养分的整体特征,利用县域耕地资源评价系统对户县耕地进行了生产潜力评价,用累积曲线分级法确定耕地地力等级。结果表明:1.地形位指数可以综合地反映地形条件的空间分布和差异信息。分布指数用于描述某种组分的实际分布与标准分布的差异,可以排除面积的干扰,户县耕地和建设用地在低地形位上的优势明显。2.不同高程和坡度分级区域内土地利用类型组合不同,各土地类型的面积在海拔较低、坡度平缓区域占绝对优势,随着高程和坡度的上升,土地利用受人类活动的影响减少,土地利用类型减少,多样性降低。3.低海拔和低坡度区域,土地利用类型转换频率快,而随着海拔和坡度增加,土地利用格局较稳定,25度以上区域尚存在部分耕地,这说明还有一定退耕还林的空间和余地。运用DEM和土地利用图建立的三维景观图能够直观显示土地利用空间格局与自然环境的关系,证实了自然因子作为土地利用分布的环境基础,在某种程度上制约着土地利用格局的基本模式。与传统的高程和坡度描述方法相比,地形位指数可以更加综合地反映出地形空间分异的细节信息。4.户县有机质水平处于中等水平,全县耕地土壤的有机质平均含量为16.93g/kg,含量大于16g/kg而小于18.0g/kg的面积达3263.581hm~2,占总耕地面积的56.45%,所占耕地面积最多;耕地土壤的碱解氮含量65.71g/kg,也处于中等水平,与土壤有机质具有较好的相关性,土壤有机质含量高的地方,碱解氮含量也高;有效磷,含量小于25mg/kg的面积有33789.62hm~2,占总耕地的81.99%,主要集中在16-18mg/kg之间,占53.16%;耕地土壤速效钾含量较高,平均为137.48mg/kg,最高186.18mg/kg,最少为80.32mg/kg。土壤速效钾含量主要集中在120-150mg/kg之间,面积有26556.99hm~2,占耕地面积的64.44%。5.在县域耕地资源评价信息系统支持下,应用层次分析对户县耕地生产潜力进行了评价,其结果显示全县耕地生产潜力较高,其中一级耕地2530.39hm~2,占耕地面积的6.14%,二级耕地19407.49hm~2,占47.09%,三级耕地12426.87hm~2,占30.15%,四级耕地4464.56hm~2,占10.83%,五级耕地2385.13hm~2,占5.79%。6.户县耕地地力的高低与土壤类型、坡度、地形地貌等有密切关系,分布规律明显,随着耕地地力等级的提高,地貌类型从较为平缓的河漫滩地和位于山区的坡地向位于黄土台塬、洪积扇灌溉条件较好的的平地过渡。更多还原

【Abstract】 Taking Huxian, which is a county located in the Guanzhong plain, Shaanxi province, as an example, Analysis of the 1985 and 2009 land use cover change and the study has explored the spatial distribution of land use and analysed the land utilization degree of different terrain gradients within Huxian with data from the Second Soil Survey (SSS), Terrain Bits Index (TBI) and Integrated Land Utilization Degree Index (ILUDI). Besides, based on several Geographical Information System sofewares, for example ArGIS, and Geostatistics, the spatial distribution of soil nutrition in Huxian has been studied. Also the production potential evaluation has been done by using Cultivated Land Resource Evaluation Information System (CLREIS) and Cumulative curve classification method was used to determine the cultivated land fertility level.Results are shown as follows:1) Terrain index was able to comprehensively reflect the spatial distribution and differences of terrain conditions. Distribution index was developed to describe the discrepancy between actual and standard distribution of one component, overcoming the disturbance caused by area. It was concluded that Huxian cultivated lands and construction lands tend to have more advantages on lowlands.2) The combination of land-use types were various in areas of different elevations and gradient grades. Areas of all land-use types were dominant at regions of low altitude and gentle slope. However, the land-use diversity decreased with the increasing altitude and slope followed by the reduced impact of anthropogenic effects.3) Land use type converted amongst one another frequently in areas of low altitude and gentle slope. Nevertheless, land use pattern appeared to become relatively more stable when altitude and slope increased. Some cultivated lands still existed on slopes above 25 degrees, which provided the implication for reforestation. The 3D landscape diagrams, which were established using Digital Elevation Models (DEM) and land use maps, offered an effective way to display the links between land use spatial pattern and environmental factors, and this proved that as the base of land use distribution, natural factors restricted the general land use pattern in some degree. TBI could reflect more detailed information of terrain spatial differentiation compared to traditional altitude-slope description methods.4) Soil organic matter content in Huxian was in the medium level. Average soil organic content of cultivated lands was 16.93g/kg, 3236.581hm~2 of cultivated lands, which equalled 56.45% of the total area, contained organic content between 16.0g/kg and 18.0g/kg. Meanwhile, the soil alkali-hydro nitrogen content was 65.71g/kg and also lied in medium level, having a good correction with soil organic matter. That is to say, high soil organic content places had high alkali-hydro nitrogen content as well. For rapidly-available phosphorus, 33789.62hm~2 of cultivated lands, which equalled 81.99% of the total area, held less than 25mg/kg with more concentrated between 16 and 18mg/kg accounting for 53.16% of total land areas. Content of soil rapidly-available potassium was relatively higher, with concentration on 120-150mg/kg occupying 26556.99hm~2, which was equivalent to 64.44% of the total cultivated areas. The average, top and bottom content were 137.48mg/kg, 186.18mg/kg and 80.32mg/kg, respectively.5) The assessment of production potential of Huxian cultivated areas has been completed using hierarchical analysis supported by Geographic Information System (GIS) and CLREIS. It was concluded that Huxian cultivated lands had relatively high production potential, and could be divided into five levels. Level one, 2530.39hm~2 accounting for 6.4% of total arable areas; Level two, 19407.49hm~2, 47.09%; Level 3, 12426.87hm~2 equivalent to 30.15% of the total; Level 4, 4464.56hm~2 covering 10.83% of the total ; Level 5, 2385.13hm~2 standing for 5.79% of the total.6) The soil fertility level of Huxian cultivated, landform lands was closely related to terrain, soil type and slop etc., showing markedly regional distribution. In response to soil fertility rises, physiognomy types transferred from flood lands and sloping lands to some well-irrigated flat grounds such as loess tablelands and flood accumulate fans etc.更多还原