30多年来呼伦贝尔草原沙漠化的演变特点及防治对策研究

采用遥感技术与野外调查相结合的方法,通过3个典型小区对呼伦贝尔草原30多年来的沙漠化演变特点进行了系统研究。结果表明:该区的樟子松林区发生着强烈的沙漠化逆转,许多地段已转变为非沙漠化土地;其它地区除部分地段由于人类的积极治理而发生沙漠化逆转外,仍处于不断发展的过程中。因此,对于樟子松天然分布区,可充分利用樟子松的优良防风固沙特性和较强的扩展能力来防治沙漠化,而对其它地区则应以封育为主,加强人工抚育和草原建设。

THE EVOLUTION CHARACTERISTICS OF SANDY DESERTIFICA TION IN HULUNBUIR STEPPE DURING THE PAST OVER 30 YEARS AND ITS CONTROL STRATEGIES

Using method combining remote sensing technique and field investigation, this article systematically studied the evoluting characteristics of sandy desertification in Hulunbuir Steppe with three typical tracts including Amugulang town, Cuogang pasture farm and Huihe forest farm during 1960-1994. The grades of sandy desertified lands used in this research are determined by means of the grading standards of sandy desertified lands, which takes aeolian landforms as principal indicators, and Sandy Desertification Index (SDI) and Sandy Desertification Ratio (SDR) as the degree of sandy desertification and the percentage of real sandy desertified lands to the sum of this desertified land and the sandy lands susceptible to sandy desertification at any time. Three sandy desertification maps of two periods and relevant data show that:① The reversion of sandy desertification has developed strongly in the eastern fringe of this region, where is covered by dense Pinus sylvestria var. mongolica forest at present, and some large sandy desertified lands have been transferred into normal productive lands. For instance, the SDI and SDR at Huihe forest farm have all declined steeply during the past over 30 years, and their decreasing ratios are 5890% and 5079% respectively. ② Although the reversion of sandy desertification has emerged in some places due to man's intentional rehabilitation, sandy desertification is developing continuously in the past 35 years. Amugulang town is the most severe desertified area, where the SDI and SDR have increased by 10455% and 7241% respectively. Cuogang pasture farm is the second most severe site, where the SDI and SDR have increased by 7500% and 3158% respectively. Therefore, in the area of Pinus sylvestris var. mongolica forest, combating sandy desertification is to wisely use excellent properties of Pinus sylvestria var. mongolica in preventing wind and fixing shifting sand as well as the ability of rapid expanding, but suitable stand density and age structure should be maintained in order to prevent reccurence of shift sand in the areas naturally occupied by this species; In the other areas, the main controlling measures are closing sanddune fields, improving management, and establishing artificial grasslands which have high quality and abundant forage and rational grazing systems to make local animal husbandry to be intensive and develop sustainably.