陇中黄土高原主要造林树种细根生物量分布

以2 mm为粗、细根的划分界限，采用根钻法对黄土高原安家沟流域油松、白杨、山杏、刺槐、沙棘和柠条6个主要造林树种细根分布进行研究，并测定不同林地下土壤含水率和土壤理化性质.结果表明： 在水平方向上，油松细根生物量呈先增大后减小的二次多项式分布，其他5个树种细根生物量均呈对数分布，水平根系发达，细根主要分布在冠幅半径2~3倍的范围内，表明各植被通过水平扩展来获取更多的土壤水分.在垂直方向上，随着土层深度的增加，细根生物量均呈减小趋势.6种植被细根生物量与土壤水分、容重呈显著负相关，与有机质、全N含量呈显著正相关.

Distribution of fine root biomass of main planting tree species in Loess Plateau,China.

The distribution of fine roots of Pinus tabuliformis, Populus tomentosa, Prunus armeniaca, Robinia pseudoacacia, Hippophae rhamnoides, and Caragana korshinskii was investigated by using soil core method and the fine root was defined as root with diameter less than 2 mm. The soil moisture and soil properties were measured. The results showed that in the horizontal direction, the distribution of fine root biomass of P. tabuliformis presented a conic curve, and the fine root biomass of the other species expressed logarithm correlation. Radial roots developed, the fine root biomass were concentrated within the scope of the 2-3 times crown, indicating that trees extended their roots laterally to seek water farther from the tree. In the vertical direction, the fine root biomass decreased with the increasing soil depth. Fine root biomass had significant negative correlation with soil water content and bulk density, while significant positive correlation with organic matter and total N contents.