近30年来北方农牧交错带沙质荒漠化动态变化

中国北方农牧交错带是沙质荒漠化发展最迅速的地区，随着自然环境变化和人类活动的加强，沙质荒漠化有愈演愈烈的趋势。为搞清沙质荒漠化的地质成因，采用以遥感为主要技术手段，结合地面，对其沙质荒漠化现状进行调查；并利用不同时期遥感数据对比，研究变化发展趋势。结果表明，全区共有沙质荒漠化土地290512．53km^2，占全区总面积的23．67％；近30多年来，中国北方沙质荒漠化土地面积增加了7369．71km^2，平均每年增加294．79km^2。就沙质荒漠化发生、发展而言，地质背景是内因，干旱大风气候是条件因素，人类活动是“催化剂”。

State and evolution trend of desertification in agro-pastoral transitional zone in northern China for last 30 years

Ago-pastoral transitional zone in northem China is the most rapid area of desertification in China. With the more and more strong of human activities and the changes of nature environment in the area, the trend of desertification became more seriously. In order to understand the geological genesis ofdesertification in the area, under the support project of Geological Survey of China, by means of remote sensing, GIS technology and field investigation, the authors investigated the status quo and compared the desertification in the different period in ago-pastoral transitional zone in northern China. The result indicats that the total desertification area is about 290,512.53 km^2, take about 23.67% of the total area of the zone in China. The trend is deterioration within 30 years. The total desertification area was 7,369.71 km^2 increased, the annual increased area is about 294.79 km^2, In view of the formation and evolution of desertification, geological background is the basic cause, the dry and windy weather is condition, and the human activity acts as accelerantor.