Advances in Earth Science ›› 2003, Vol. 18 ›› Issue (2): 257-262. doi: 10.11867/j.issn.1001-8166.2003.02.0257

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BIOLOGICAL MECHANISM OF SANDY DESERTIFICATION IN GRASSLAND RECLAMATION AREA IN NORTH CHINA

Zhao Wenzhi,He Zhibin,Li Zhigang   

  1. Cold and Arid Regions Environmental and Engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China
  • Received:2002-05-14 Revised:2002-10-30 Online:2003-04-10 Published:2003-04-01

Zhao Wenzhi,He Zhibin,Li Zhigang. BIOLOGICAL MECHANISM OF SANDY DESERTIFICATION IN GRASSLAND RECLAMATION AREA IN NORTH CHINA[J]. Advances in Earth Science, 2003, 18(2): 257-262.

Grassland comprises an important part of land resource in North China. In recent decades, grassland desertification is more and more serious and becomes one of the most serious environmental and social-economic problems in North China. Thus, a better understanding on the biological mechanism of grassland desertification is required for combating grassland desertification and for appropriate management and conservation of environment. We exploited the results of desertification research obtained from Bashang area as a typical district of slight to moderate desertification area and Korqin sandy land as the typical of severe desertification district, respectively, in combination with previous relevant research achievements, to alleviate the biological mechanism of grassland desertification. It is illustrated that desertification results in invasion of shrub which is adapted to desert environment, and thus, increase of spatial heterogeneity in soil resource and mycorrhizae. It was pointed out that shrub invasion occurs during the process of conversion of farmland to grassland and overgrazing. Shrub invasion into grassland facilitate the development of “islands of soil resource” with soil nutrients and moisture accumulated under shrub canopy. Meanwhile, the occurrence of shifting sand patches accelerated soil erosion by wind and water. Improper cultivation, irrigation,saltanization, as well as overgrazing reduce the density and inoculation rate and decrease grassland productivity. Spatial heterogeneity of soil resource and landscape on sandy land enhance with the shrub establishment and development. It is proposed that soil particle fractal characteristics could be used as an indicator of desertification, and variation coefficient as reflected by ratio of variation to average, could be used as an index of heterogeneity of soil resources.

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