Quantitative Evalution Of Comprehensive Intensity Of Land Use In Horqin Sandy Land

In the north farming-pastoral zone of China, desertification has been one of the most concerned social-economic-environmental issues on account of the fragile ecological environment and Unreasonable human activities. The intensity of land use indicates the degree of land exploiting by people, showing people’ interference on land to some extent, the unreasonable land use activities can increase the risk of land desertification. Hence, quantifying land use intensity and its effects on desertification is significant for revealing the impacts of human activities on the ecosystem of farmingpastoral zone and understanding the man-made causes on land desertification.Horqin sandy land is selected as the study area in this paper. The land use classification maps of 1990,2000 and 2010 obtained by remote sensing, meanwhile, extract the net primary productivity(NPP) of vegetation in the study area, based on NPP of different land use type and economic output, identify the indicator of comprehensive intensity of land use(CILU) when take the different land use structures into consideration. CILU refers to the relative pressure of regional land production on the land production potential, the interpretability of CILU to desertification is also analyzed. The result of this research are as follows:(1) Cultivated land、woodland and grass land are the main land use types in Horqin area. The proportion of the Three land use type to the Horqin area are 72.02%、68.68% and 77.94% in 1990、2000 and 2010, grass land area accounts for the highest proportion;(2) There is a decreased tendency and an obvious regional characteristics of NPP. The value of NPP are 100.438gC/m2、76.375gC/m2 and 71.967gC/m2, the counties of NPP value are relatively low in Horqin sandy land gradually aggregate to the central area.(3) The use intensity of cultivated land 、woodland and grass land increase over time for most of the studied counties. The maximum land use intensity of different types all occurred in Horqin area, the value are 1.18×10-3 yuan/gC、4.74×10-3 yuan/gC and 7.58×10-3 yuan/gC.(4) There is an increased trend for CILU. In 1990, the CILU is relatively low in most areas of Horqin sandy land; in 2000, the CILU increase obviously and the counties of higher CILU aggregated in eastern Horqin; in 2010, the value of CILU decrease to 2.32×10-3 yuan/gC, and the counties of higher CILU also concentrated in eastern Horqin.(5) In the model shows the relationship between CILU and desertification, the coefficients of CILU are positive when rainfall and the effects of the surrounding bare sandy land are taken into consideration; the model of the relationship between classified land use intensity and desertification, land use intensity of cultivated land、woodland and grass land all haven’t passed the test.Based on the results upon, we conclude that CILU can effectively quantify human activities which impact desertification and can characterize desertification to some extend when integrate rainfall and the effects of the surrounding bare sandy land.