干旱区新垦绿洲人工防护林土壤物理特性及其生态意义

 结合灌溉量和树种特征，分析了新垦绿洲克拉玛依农业开发区3个不同树种人工防护林带下土壤容重、总孔隙度、饱和含水量和含水量变化。结果表明,各树种防护林带下土壤物理性质存在垂直变异，其中土壤容重基本呈随着土层深度增加而逐渐增加的趋势，树种种类对土壤容重的影响不大；饱和含水量随着土层深度增加基本呈逐渐降低的趋势，树种种类对土壤饱和含水量影响不大；土壤总孔隙度在不同土层间均存在显著差异。俄罗斯杨和胡杨林带下土壤含水量均呈现出随土层深度增加而增加的趋势。在灌溉量相等且灌溉后经过相同时间的条件下，不同树种林带下在同一土层的土壤含水量存在差异，而在同一树种林带下，灌溉量大小对土壤含水量有影响。从改良土壤结构的角度来说，在选择构建绿洲防护林体系树种时，俄罗斯杨、榆树、胡杨林这3个树种具有同样的优势；从节约用水的角度来说，在防护林树种选择中胡杨比俄罗斯杨的优势大。

Physical Properties of Soil in Shelterbelts of a New-cultivated Oasis in Arid Region and its Ecological Significance

Variations of bulk density, total porosity, saturated moisture content and moisture content of soil with different irrigation volume and tree species in shelterbelts in Karamay agricultural development zone, a new-cultivated oasis, were investigated. The results indicated that the measured soil physical properties displayed a vertical variance among different soil layers. Soil bulk density gradually increased with soil depth increasing, and difference of tree species did not exert an influence on it. Saturated moisture content also showed a similar pattern, and difference of tree species did not exert an obvious influence on it. Total porosity existed a significant difference among soil layers, and difference of tree species did not show effect in soil total porosity. Under different irrigation volume, soil moisture contents in Populus russkii Jabl. and Populus euphratica Oliv. shelterbelts showed a tendency of increasing with depth rising. Under same irrigation volume and post-irrigation time, the soil moisture content at the same layer displayed a significant difference under different shelterbelts. Moreover soil moisture content was affected by the irrigation volume. When shelterbelts were constructed for improving soil structure, Populus russkii Jabl., Ulmus pumila Linn. and Populus euphratica Oliv had the same advantage. However, Populus euphratica Oliv gained the advantage over Populus russkii Jabl. for water saving.