【作者】 陈凤娟；

【导师】 张晓萍；

【作者基本信息】 西北农林科技大学 ， 地图学与地理信息系统， 2011， 硕士

【摘要】 长武县位于陕西长武渭北旱塬区,是典型旱地农业区,也是黄土高原水土流失严重区。近30年来在国家政策影响下,不仅成为全国退耕还林(草)试验示范县,而且经历了由陕西省粮食基地转化为粮果基地的过程,土地利用/覆被发生了巨大变化。本文以长武县为研究区域,以1983年全国第一次农业区划、1993年全国第一次土地利用详查等历史数据、2009年全国第二次土地利用调查成果,以及县统计年鉴等数据为基础,调查和分析了长武土地利用以及耕地数量历史演变,耕地质量及空间分布,明确耕地及其后备资源数量、变化及驱动因素,为该区经济稳定发展和粮食安全提供科技支持。主要结论有:(1)长武县2009年土地利用现状格局以耕地、园地、林地和草地为主。其中面积分布最广的是林地,全县林地面积为179.99 km~2,覆盖率为31.74%。其次是耕地,面积为159.62 km~2,占全县面积的28.15%。园地和草地的分布面积分别为83.57 km~2和76.20 km~2,分别占全县面积的14.74%和13.44%。居民地的分布面积为49.76 km~2,只占全县耕地面积的8.77%,水域和未利用地分别占全县面积的3.04%、0.13%。(2)对长武县1983～1993年和1993～2009年土地利用变化过程进行了分析,认为,1983～2009年间耕地处于持续减少趋势,两个时期中,分别减少了71.64 km~2、58.23 km~2。园地、林地和草地面积处于持续增加趋势,1983年园地面积仅为18.26 km~2,1993年增加了1.7倍,2009年较1983年增加了3.6倍。两个研究期林地分别增加了36.85 km~2和28.15 km~2;草地总面积增加了28.33 km~2。30年中水域面积呈减少趋势,居民地面积变化不明显,而未利用地一直保持较大的减少速率。景观格局变化趋势表现为:斑块破碎程度加大,形状指数增加,而斑块分维度减少后增加。(3)对长武县1983、1993和2009年耕地数量及地形分布演变特征分析表明:总体上,长武县塬面和沟坡耕地面积呈持续下降态势,川地耕地面积有所上升。1983-1993年和1993-2009年塬面耕地面积分别减少了17.02 km~2和23.46 km~2,主要是向园地和居民地转化。坡耕地分别减少了56.59 km~2和36.36 km~2,主要转向园地、林地、草地和居民地。川地耕地面积分别增加了1.98 km~2和1.28 km~2,第一阶段主要是有草地转入,第二阶段主要是由于水域面积减少所致。(4)结合社会经济统计资料初步分析长武县耕地数量变化驱动力,归结为:社会经济发展、农业现代化水平的提高和国家实施退耕还林还草等宏观政策的实施。更多还原

【Abstract】 Changwu County, located in Weibei Plateau area, is a typical region for dryland agriculture, also the most eroded area in the Loess Plateau. In terms of land use/ coverage, the county has changed remarkably in the latest 30 years under the guidance of state policies, becoming a national demonstration county of Grain for Green, but also experiencing the conversion from grain base to grain-fruit base of Shaanxi Province. Therefore, Changwu County is selected as a case study in this article and an analysis is made of land use types, change in farmland quantity and quality and its spatial distribution to determine its driving factors, which is aimed to provide scientific supports for the sustainable development of economy and food security of the county. The main conclusions obtained are as follow:(1) In 2009, Farmland, orchard, forest land and grassland are the main patterns of land use in the county. Forest land, the most widely distributed type, took up an area of 179.99 km~2, accounting for 31.74%, followed by farmland, orchard, grassland and residential land, occupying 159.62 km~2 (28.15%), 83.57 km~2 (14.74%), 76.20 km~2 (13.44%), 49.76 km~2 (8.77%) respectively. While waterbody accounted for only 3.04% and unused land 0.13%.(2) The dynamic analysis of land use change of the county in 1983-1993 and 1993-2009 shows that farmland declined continuously throughout the two periods, by 71.64 km~2, 58.23 km~2 respectively, while orchard, compared to the initial 18.26 km~2 in 1983, increased by 1.7 times in 1993 and 3.6 times in 2009. Forest land rised by 36.85 km~2 and 28.15 km~2 respectively at the end of each period, and grassland by 28.33 km~2. We can also see that residential land did not significantly change, waterbody decreased somewhat, and unused land decreased at a considerable rate over the 30 years. The trend of the landscape pattern is characterized by: the increase in degree of patch fragmentation, in shape index, and in the patch fractal dimension after decrease.(3) The quantity and topographic distribution of farmland in 1983-1993 and 1993-2009 show that farmland on the plateau and on the slope of gully declined continuously, while that on the valley experienced a rise in area. In 1983-1993 and 1993-2009, farmland on the plateau decreased by 17.02 km~2 and 23.46 km~2 respectively, mainly converting to orchard and residential land; one on the slope of gully decreased by 56.59 km~2 and 36.36 km~2 respectively, mainly transforming to orchard, forest land, grassland and residential land; and the other on the valley rose up by 1.98 km~2 and 1.28 km~2 respectively, converting largely from grassland in the former period and from waterbody in the latter one.(4) With a preliminary analysis of the socio-economic statistics combained, the driving force for farmland use change in Changwu County are concluded as the development of socio-economy, the advancement of agricultural modernization and the implemetation of national Grain for Green policy.更多还原