不同地形条件对沙漠植物生长和沙地土壤水分的影响

对沙坡头地区人工植被固定沙地内不同地形条件下土壤水分和植物生长的变化进行了研究。结果表明,沙地土壤水分的变化以及植物生长的变化依照不同的地形条件表现出一定的规律性。沙地土壤水分含量由高至低的变化趋势根据地形条件依次表现为:丘间低地>迎风坡>坡顶>背风坡;灌木植物密度和盖度与土壤水分变化密切相关,由大到小的变化趋势同样为:丘间低地>迎风坡>坡顶>背风坡;而草本植物密度和盖度可能还受结皮等其它环境因素的影响,由大到小的变化趋势为:背风坡>坡顶>迎风坡>丘间低地。

Effects of the fixed dune topography on soil water and plant growth

The artifical sand-fixing vegetation in Shapotou region,which were planted under no irrigation condition,was situated in the southeast of Tengger Desert.Changes of the soil moisture and the vegetation growth in this area were closely related to the landform of the fixed dunes.Four kinds of typical landforms were selected and five samples were designed on each type of terrain.The density and coverage of plants and the soil moisture were measured every month in growth season.The results showed that effects of the fixed dune landform on soil water and plant growth were obvious and the changing patterns of soil water and plant growth were identified based on the topography.Soil water content changed from high to low according to the following sequence:lowland,windward slope,the top of dune and leeward slope.The density and coverage of shrubs had the same changing tendency with soil moisture.However,the density and coverage of herbs was on the contrary and changed according to the sequence:leeward slope,the top of dune,windward slope and lowland.All these results provided evidences for the conclusion that the major effective factor on shrub plant structure was soil moisture in different landform,but to herbs,may be the microbe crust and other environment factors in the different landform,which should be studied further more.