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| Effects of Salix psammophila checkerboard sand barrier on dune sand grain size composition and characteristics |
(Forestry School of Shandong Agricultural University，Shandong Province Key Laboratory of Soil Erosion and Ecological Restoration，
Taishan Forest Ecosystem Research Station，271018，Taian，Shandong， China) |
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Abstract The study adopted the way of combining the field investigation and laser particle analyzer test indoor. Taking the quicksand dune as control and the sand dunes of Salix psammophila checkerboard sand barrier of 2 years and 7 years as the research objects, the regulation of soil grain size characteristics of surface layer (0-5cm) and sub-layer (5-10cm) on different parts of dunes was studied, which demonstrate the effects of sand barrier on the grain size composition and characteristics of the sand dune. The results indicated that: 1）Kubuqi Desert was mainly formed with fine soil and medium sand. There was little difference on fine clay volume fraction between the layers of the three types of dune, whereas other size volume fraction of the quicksand dune showed no significant difference with 2a barrier dune, and both of two kinds dunes were obvious significance with the 7a barrier dune. 2）The grain size parameters between layers of three types of dunes shared the same changing rule. The rule of Mz and SK was 7a barrier dune＞ quicksand dune＞2a barrier dune, while that of σ and Kg was 7a barrier dune＞2a barrier dune＞ quicksand dune. With the time increasing, different kinds of three dunes shared the same rule that the sorted behavior became weaker, skewness became from nearly symmetric to normal distribution, and kurtosis value became larger. 3）The changing rule of each grain size parameter of the dunes in different parts was not completely same. Concerning different parts of each dune, Mz of quicksand dune and 7a barrier dunes was significant difference in surface layer except 2a barrier dune, but the sublayer showed the opposite. As the different parts and layers, sorting coefficient and skewness shows notably different. Kg in different parts was significantly different except 7a barrier dune. With the time increasing, the particle size became finer, the sorting coefficient gradually became weaker，and the Skewness and Kurtosis became larger.
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Received: 21 September 2012
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