Remote sensing image based information extraction for land salinized degradation and its evolution

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 temporal multi-spectral images of 1987, 1998 and 2005, this paper explored the sensitive bands of salinized soil through spectral property analysis, established land degradation index to delineate salinization information obviously. Land degradation information of three periods were derived from remote sensing images to analyze the area, spatial distribution and evolution of degraded lands. Our results indicated that Kenli County had much heavy and moderate degraded land 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 human disturbance and overusing land resources, the land degradation status appeared a deteriorating trend to 2005. The main trend between 1987 and 1998 was the conversion of degenerated land to agricultural land, and that in 1998-2005 was the conversion of degenerated land to reservoirs and culture ponds, as well as conversion from agricultural land to degenerated land due to salinization. Human activities played 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.