基于遥感图像的垦利县盐碱退化土地信息提取及其演化规律研究

Remote Sensing Image-Based Information Extraction for Land Salinized Degradation and Its Evolution in Kenli County

选择黄河三角洲滨海盐渍土地分布区,以垦利县为例,利用1987,1998和2005年三期多光谱遥感影像,通过研究各地物的光谱特性,找出土地盐渍化的敏感波段,通过波段间的组合构建了突出反映盐渍化信息的土地退化指数,并通过遥感图像分级获得三期遥感影像的土地退化等级分布,进而分析研究区退化土地的等级、面积、分布,及其土地退化的动态演化规律。结果显示,1987年垦利县重、中度退化土地较多,二者占总土地面积的1/2。经过11年的努力,至1998年土地退化状况得到明显改善。但由于人类活动干扰及对土地资源的过度利用,2005年土地退化状况又呈现变差的趋势。退化土地转为农用地是1987—1998年时段的主要变化趋势,而1998—2005年时段的主要变化趋势则是退化土地转为水库和养殖池,及其农田因盐渍化而沦为退化土地。人类活动在研究区土地退化的演变中起着主要作用。

Land degradation has been a global problem, of which salinized degradation is the important type. Choosing coastal saline soil distribution area of the Yellow River delta, taking Kenli County as an example, using three periods multi-spectral images of 1987, 1998 and 2005, this paper found out the sensitive bands of salinized soil through spectral property analysis, established land degradation index to delineate salinization information obvi- ously. Land degradation information of three temporals were derived from remote sensing images to analyze the area, spatial distribution and evolution of degraded lands. The results indicated that Kenli County had much heavy and moderate degraded lands in 1987, which accounted for 1/2 of the whole area. Through 11 years efforts, land degradation status had been obviously improved up to 1998. But because of artificial disturbance and overusing land resources, the land degradation status appeared a deteriorating trend to 2005. The main trend between 1987-1998 was the conversion from degenerated land to agricultural land, and that of 1998-2005 was the conversion from degenerated land to reservoirs and culture ponds, as well as conversion from agricultural land to degeneratedland due to salinization. Human activities played an important role in land degradation evolution in the study area. Our study, explored remote sensing extraction method for salinized degradation information. It has positive significance to the sustainable utilization of land resources and ecological protection in the Yellow River delta region.