Grain Size of Land Surface Deposits in a Vegetation Restoration Region of the Alpine Sandy Land in Qinghai, China
Received date: 2014-10-17
Revised date: 2014-11-24
Online published: 2015-01-20
The Gonghe Basin is a typical alpine arid and semi-arid sandy land, located in northeast of the Qinghai-Tibet Plateau, China. In 1958, the Sand-control Experimental Station of Qinghai Province was set up in Shazhuyu, one of the most serious desertification regions in the Gonghe Basin, to explore a suitable technology for cold sandy land restoration. After 50 years, Shazhuyu became a representative integrated renovation region for cold arid desertified land, forming a special oasis protection system, which is composed of areas of resorting vegetation by enclosure, stabilizing sand dunes by afforestation and protecting farmland by network of forest. We choose the typical sand-fixation plants Caragana korshinskii and Salix microstachya controlling in different years on sand dunes and lowlands to probe into the change of characteristics of land surface deposits from topsoil to the depth of 60 cm. Results show that the sediments in Shazhuyu are dominated by fine sand, consistent with other Chinese deserts' particles, while a clear difference made from sandy land in the Qinghai Lake Basin which was separated by the Qinghai South Mountain. Meanwhile, sediments in lowlands were phase alternating by aeolian sediments and river deposition. Even after decades of vegetation restoration on mobile dunes, soil mechanical composition was still dominated by sand, with clay and silt content increasing. It had a great effect on the top 5 cm soil texture when setting clay sand barrier. Following the years of governance, the role of water and chemical weathering happening, the clay gradually disappeared and the soil began to formation. Directly broadcasting C. korshinskii seed could promote refinement of sediments on surface 60 cm soil layer, especially, top of 5cm much finer. Meanwhile, the change of the soil particles related to vegetation growth and source of materials, particularly the distribution of vegetation. Because of the different initial states of existence in lowlands, the effect of Salix microstachya to grain size is difficult to describe.
Tian Lihui , Zhang Dengshan , Peng Jiping , Wu Wangyang , Zhang Pei . Grain Size of Land Surface Deposits in a Vegetation Restoration Region of the Alpine Sandy Land in Qinghai, China[J]. Journal of Desert Research, 2015 , 35(1) : 32 -39 . DOI: 10.7522/j.issn.1000-694X.2014.00186
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