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Fujian Agriculture and Forestry University (2015)

Aeolian Sand Movement Law in Coastal Frontier and Effect on the Casuarina Protection Forests

陈德志;

Titre : Aeolian Sand Movement Law in Coastal Frontier and Effect on the Casuarina Protection Forests

Auteur : 陈德志;

Grade : Master’s Theses 2015

Université : Fujian Agriculture and Forestry University

Résumé partiel
Laws of wind-blown sand movement in the coastal front zone and plant function mechanism is an important part of coast ecology,the research which is based on the blown sand Physics as basic principles, combining theories of forestry, ecology and other subjects is about the characteristic of wind and sand movement and the effect on Casuarina equisetifolia plantation, The objection is to provide the theoretical base and scientific methods to control blown sand hazard and improve the eco-environment in the coastal area of Southern China, the field determination about the sand and wind movement and the effection of the protection forest was made, based on summary of the research fruits of predecessors, three line transect which were parallel to the main wind direction were laid according to the different underlying surface types, the line transect started from the grand calorie climax, followed by Om,5m, 10m,20m,40m and 80m,six different sample points, with experiments outdoors and investigation as main method at Chihu forest farm in chongwu, combining with the analysis of the data of dusty wind weather,studies the whole system composed of blown sand moving process mainly with parallel movement and particle falling process mainly with vertical movement. After anlysis and study, initial results were got as following:1. With the distance to the windward side increased, the speed of different height in each measuring position of forestland and grassland substantially decreased gradually, and the Windbreak efficiency in forestland showed a rising trend on the whole.2. In the three different plots, the soil bulk density was relatively great, the capillary porosity, non capillary porosity, total porosity were relatively small, the soil nature water content was medium in bare land, the soil bulk density was medium, the capillary porosity was relatively great, non capillary porosity was small, the total porosity and soil nature water content were medium in the grassland while the soil bulk density was small, the capillary porosity was relatively, non capillary porosity,the total porosity and soil nature water content were relatively great in the forest land, the capillary porosity, the value of the total porosity and soil nature water content in upper layer increased with the distance from the coast increased, reached the maximum at 40m.3. The surface sand samples in this region are dominated by fine sand, medium sand and coarse sand decreasingly in three different underlying surface, but there were significantly different between the content. Because of the degree of accumulation of sand, the grain size become bigger with the distance increased, the protection forest had the most obvious change and the coarser grain size, the grain size of sub-surface (below 100 mm) were coarser than the surface in the protection forest land and the grassland, but not in the bare land. Due to the coarser grain size, the protection forest land had the highest average particle size, biggest standard deviation is and the highest degree of negative bias compared with the grassland and bare land. Because of the pneumatic separation, there is remarkable correlation between average particle size and other particle size parameters in grassland and bare land, the coarse sand and very coarse sand showed very significant positive correlation with the silty sand so that we could use the content of the coarser sand to distinguish the protection effect of the protection forest, it meant that the coarser sand in the coastal front zone, the better protection effect it had. there was a certain correlation between the characteristics of grain size parameters, the sorting became better and the skewness tended to be positive while the average particle size of sediment became finner. The kurtosis tended to be flattened in grassland and bare land, no significant trends or alterations of kurtosis were observed in forest land.

Mots clés : Coastal frontier; Sand and wind movement; Casuarina equisetifolia; Protection forest;

Présentation (CNKI)

Page publiée le 4 avril 2018