G111公路讷嫩段8种护坡灌木根系增强土壤抗冲性比较

Comparison of Soil Antiscouribility Enhanced by Eight Shrub Roots at the Section from Nehe to Nenjiang of G111 Highway

国道G111讷嫩段是较严重的风沙区,选择固沙效能较高的植物在公路边坡植被恢复中具有重要意义。因此,选取8种常见高速公路绿化灌木,以全根挖掘法考察其根系分布特征。采用原状土冲刷水槽法,比较不同灌木根系土壤抗冲性大小,最后用主成分分析法对其根系大小、数量及土壤理化特性进行分析。结果表明:(1)8种灌木根系在土壤中分布形态差异很大。在垂直剖面上,紫丁香、东北连翘、辽东水蜡、红王子锦带、侧柏呈"甲"字形分布;红瑞木、毛樱桃、树锦鸡儿分别呈"由"、"T"、"干"字形分布。(2)同一灌木对土壤抗冲性的增强效应随土层深度增加而减小,随坡度增大而减小,随雨量的增大而减小;(3)在主成分分析中,得出有机质、速效钾含量及小于1 mm的根系生物量、根系长度在植物对土壤抗冲性增强效应中起主要作用。在大雨条件下更为明显,它们的公因子方差分别为0.99,0.98,0.98,0.97。(4)8种灌木对土壤抗冲性增强效应依次为紫丁香、东北连翘、红瑞木、辽东水蜡、红王子锦带、侧柏、毛樱桃、树锦鸡儿,建议对前4种推广应用。

The section from Nehe to Nenjiang of G111 highway is one of the most windy desert areas in this region.It is very easy to form the soil erosion regions after the road construction in this area.Therefore,it is very important to choose the species which have the root system of solidifying soil and decreasing water loss for the vegetation recovery at road side.The root characteristics of eight shrubs were examined by digging the whole root system out.The soil antiscouribilities of different shrub root systems were identified using the undisturbed soil trough scouring method.Then,the size and amount of different shrub roots and the physiochemical characters of the soil were analyzed with the principal components analysis.The result showed that：（1）The root distribution in soil for eight shrub species had great difference;（2）The soil antiscourability for the same species increased with the increase of the soil depth,decreased with the increase of the slope and decreased with the increase of the precipitation;（3） The biomass of the roots whose length are less than 1 mm,the length of the whole root,and the contents of organic matter and available potassium were very important to determine the soil antiscourability by the principal components analysis,which had stronger effects under the heavy rain washing.The common factor variances for above root and soil factors in the principal component analysis were 0.99,0.98,0.98,and 0.97 respectively;（4） The order of the soil antiscourability for eight shrubs is Syringa oblata,Forsythia mandshurica,Cornus alba,Ligustrum obtusifolium subsp.suave,Weigela florida,Platycladus orientalis,Prunus tomentosa and Caragana arborescens.We recommended the first four species as the plants of vegetation recovery in this area.