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为了探讨重大工程的生态环境效应,从风沙环境、土壤环境、小气候、生物多样性和地下水环境5个方面对塔里木沙漠公路防护林工程的综合生态环境效应进行了研究.结果表明:(1)防护林改变了近地表风沙运动过程,防沙体系内风速、输沙率降低幅度分别达64%~80%和87.45%~99.02%,风沙流结构、沙物质粒度、地表蚀积状况也发生了明显变化;(2)与自然流沙地相比,防护林土壤容重减小,全盐含量、总孔隙度和含水量增大,土壤肥力质量明显提高,其变化基本呈现“先快后慢”的规律;(3)防护林对于小环境改善作用明显,距地面6m范围内,林地不同高度的空气温度普遍低于自然流沙地,而空气湿度则高于自然流沙地,林地土壤温度也低于自然流沙地;(4)随着防护林内生境的变化,土壤微生物种类显著增加,但不同种类微生物的种群分布并不均匀;(5)目前防护林灌溉抽水对地下水位、地下水矿化度的影响不大,水位在厘米级范围波动,矿化度的变化幅度在±1g·L-1左右,且没有明显的变化趋势.
In order to study the eco-environmental effects of major projects, the comprehensive eco-environmental effects of Tarim Desert Highway shelterbelt project were studied from five aspects of wind-blown environment, soil environment, microclimate, biodiversity and groundwater environment.The results showed that: (1) Near the surface wind and sand movement, the wind speed and sediment transport rate in the sand control system decreased by 64% -80% and 87.45% -99.02%, respectively. The wind-sand flow structure, sand particle size and surface erosion status also changed obviously. (2) Compared with natural sandy land, the soil bulk density of shelterbelts decreased, the content of total salt, total porosity and water content increased, soil fertility increased obviously, and the change showed the regularity of “fast first and then slow”. (3) The shelterbelt has obvious effect on small environment improvement. The air temperature at different height of forest land is generally lower than that of natural runoff and sand land within 6m from the ground, while the humidity of air is higher than that of natural sand and sandy land. (4) With the change of habitat in shelterbelts, the species of soil microorganisms increased significantly, but the population distribution of different species was not uniform. (5) At present, The effect of salinity is not significant. The water level fluctuates in the centimeter range, and the salinity of salinity ranges about ± 1g · L-1, with no obvious change trend.