关键词: 自然因素, 人为因素, 累加效应, 沙漠化, 科尔沁沙地

Abstract: Analyses of the data of annual air temperature, annual precipitation (identified as natural element), and cropland index and grassland carrying capacity (as human activity), with sliding average, found that the duration of cumulative impacts of annual mean air temperature and precipitation on desertification is short, generally not over four years and the effect of annual mean temperature on desertification is not significant and came to the maximum in the second year; that of precipitation on desertification is significant and reached the maximum in the fourth year with r=0.801, showing a strong correlation between these two parameters. The variation of air mean temperature and annual precipitation played a key role in the duration and intensity of cumulative impacts on desertification. Human activities, i.e. cropland index and carrying capacity of grassland imposed significant impacts on desertification in a longer time period, generally more than 8 years. The cropland index showed the most significant cumulative impacts on desertification in the seventh year while that of the carrying capacity on desertification came to a maximum in the tenth. There is a close relationship between desertification, and cropland index and carrying capacity. The root cause of the cumulative impacts of cropland index and carrying capacity on desertification is the increasing pressure on environment and resource due to increasing population.

Key words: natural element, human activity, cumulative impact, desertification, Horqin Sand Land