摘要
以农牧交错带南部的甘肃省环县为研究对象,以1949—2009年16组自然和社会经济统计数据为样本,采用主成分分析法,对引起土地荒漠化的自然因子与人为因子进行了定量分析。结果表明:(1)在环县土地荒漠化发展过程中,自然与人为因素共同作用的贡献率为49.64%,自然因素的贡献率为21.79%,人为因素的贡献率为10.89%。自然和人为因素共同的作用导致了环县荒漠化的发展,单独的人为因子和自然因素均处于较低水平;(2)在环县荒漠化发生发展过程中真正起决定作用的是人类活动,气候条件对于荒漠化的发展只起影响作用而不是决定作用。其中自然因子的影响主要是气温持续升高,降雨量减少,空气相对湿度下降,蒸发量增大导致干旱和土壤干层的发育,抑制了植物的生长,降低了植被覆盖度及土壤的抗冲蚀能力,而较强的风力及暴雨量的增加加速了土壤侵蚀;人为因子的影响主要是人口急剧增长,农业人口过大,大面积垦殖导致土地利用不合理,超载放牧引起草场大面积退化直接导致了土地荒漠化扩展。
Huanxian County of Gansu Province, located in the south part of farming-pastural ecotone, was selected as a study site, aiming to quantitative analyze the natural and anthropogenic factors of desertification in this region. Principal component analysis was conducted on 16 sets of data from 1949 to 2009. The result showed that during the process of desertification, the contribution rate of combined natural and anthropogen- ic factors could be account for up to 49.64~/oo, natural factors only contributed 21.79 ~//00, and anthropogenic factors accounted for 10.89 ~/＇00, respectively. This demonstrated that natural and anthropogenic factors were dominating factors of desertification in Huanxian County. In addition, human activities played a decisive role in desertification although climate condition also imposed substantial impacts. The effects of natural factors, including rising temperature, less rainfall, lower humidity, and higher evaporation potential restricted the plant growth and decreased vegetation coverage as well as the soil erosion resistance ability. In the other hand, stronger winds and torrential rains could accelerate soil erosion. Anthropogenic factors including rapidly increased total population, oversized agricultural population, and subsequent excessive developing and grazing are the direct factors of desertification in the study site.
出处
《水土保持通报》
CSCD
北大核心
2013年第2期203-208,共6页
Bulletin of Soil and Water Conservation
基金
中国科学院战略性先导科技专项"北方暖温性草地固碳现状
速率
机制和潜力"(XDA05050403)
甘肃省自然基金项目(1107RJZM105)
黄土高原土壤侵蚀与旱地农业国家重点实验室项目(10501-303)
关键词
荒漠化
自然因素
人为因素
农牧交错带
黄土丘陵沟壑区
desertification
natural factor
anthropogenic factor
farming-pastural ecotone
loess hilly region
