黄土丘陵区县域耕地时空格局变化及驱动因素分析——以天水市武山县为例

Spatio-temporal Pattern Changes and Driving Factors of Cultivated Land in Loess Hilly Region:a Case Study of Wushan County,Tianshui City

以黄土丘陵区武山县为研究对象,基于土地利用数据,运用变化轨迹分析法、面积加权平均差椭圆和景观格局指数以及土地利用预测模型,探究1990-2018年武山县耕地格局变化特征,判断各要素对其变化的重要程度。结果显示,(1)3个研究时段武山县耕地面积总体呈减少趋势,耕地重心不同时段存在差异,耕地重心先向西南转移再向东南转移。(2)3个研究时段武山县耕地变化都具有减少补充的基本特征,2000年前速率缓慢,2000年后速率加快,耕地减少面积比补充面积多,耕地减少以城关镇和洛门镇为主。(3)3个研究时段武山县耕地图斑呈现出破碎化现象,破碎化程度加剧。(4)3个研究时段武山县耕地发生变化的主要原因可以归纳为政策影响、自然环境因子影响、空间距离要素的影响,而受地理空间要素影响较小。综上,武山县耕地在28年间变化明显,武山县需要贯彻耕地保护政策和可持续发展理念,合理利用耕地。

Taking Wushan County in the loess hilly region as the research object,based on land use data,using change trajectory analysis method,area weighted average difference ellipse,landscape patterm index and land use prediction model,this paper explores the characteristics of cultivated land pattem change in Wushan County from 1990 to 2018,and judges the importance of each factor to its change.The results showed that,(1)the area of cultivated land in Wushan County showed a decreasing trend in the three research periods,and the center of gravity of cultivated land was different in different periods.The center of gravity of cultivated land shifted first to the southwest and then to the southeast.(2)The change of cultivated land in Wushan County in the three study periods had the basic characteristics of reducing and supplementing.The rate was slow before 2000 and accelerated after 2000.The area of cultivated land reduction was more than that of supplementary area,and the reduction of cultivated land was mainly in Chengguan Town and Luomen Town.(3)The cultivated land patches in Wushan County showed fragmentation during the three study periods,and the degree of fragmentation increased.(4)The main reasons for the change of cultivated land in Wushan County during the three research periods can be summarized as the influence of policy,natural environmental factors and spatial distance factors,while the influence of geospatial factors is small.In summary,the cultivated land in Wushan County has changed significantly in 28 years.Wushan County needs to implement the cultivated land protection policy and the concept of sustainable development,and rationally use the cultivated land.