黑河流域土地荒漠化及其变化趋势

黑河流域土地沙漠化程度与演变过程的空间分异显著,高台、临泽、金塔及额济纳旗等地,沙漠化土地占土地总面积的54.90%~64.30%,生态环境脆弱;民乐、肃南、高台、金塔及额济纳旗境内,严重沙漠化的流动沙丘所占比率较大,约占沙漠化土地面积的22.51%~35.07%,现代沙漠化强烈。近年来,中游地区沙漠化演进呈下降趋势,受气候干暖化和土壤潜在沙漠化环境影响,流域部分地区未来沙漠化将加剧扩展,但流域人类活动对流域沙漠化演变趋势有明显影响。

Land Desertification Status and Developing Trend in the Heihe River Basin

Like other inland river basins, land desertification is one of the most important problems of eco environment in the Heihe river basin. The land desertification status and developing trend are analyzed in this paper. The results indicate that the degree and process of land desertification are markedly varied in different regions of the Heihe river basin. The desertification land areas in the Gaotai, Linze, Jinta and Ejin counties have reached about 54.90%~64.20% of each total land area, and the shifting sand dune areas in the Mingle, Sunan, Gaotai, Jinta and Ejin counties reached 22.81%~35.07% of the desertification land area. The modern desertification developed quickly in the middle and lower reaches of the Heihe river basin. In late years, because of the largely administering action of desert, the developing rate of land desertification has been reduced in the middle reach, such as in the Zhangye and Jinta counties, of which the rate was reduced by 2.40% and 5.90% respectively. After 1990, the desertification developing rate in the Jinta and Zhangye counties is 0.5% and 0.09% respectively. However, in the lower reach, the desertification was developed speedily still, and the desertification rate in the Ejin Banner reached 5.60%. Affected by the climate drying and warming trend, the exploitation of water resources and the potential desertification environment of soils, the developing trend of land desertification in some regions in the Heihe river basin would be intensified in the future. The human activities may take an important play for changing the trend of the land desertification. In order to reduce the developing rate of desertification or reverse the desert process, rational and thrifty utilization of water resources in the entire basin is the key factor.