高原山地丘陵区马尾松近成熟林和成熟林细根的垂直分布特征

Vertical distribution characteristics of fine roots of near-mature and mature Pinus massoniana plantations in hilly areas in plateau mountainous region

为研究高原山地丘陵区马尾松(Pinus massoniana)近成熟林和成熟林细根(直径≤2 mm)垂直分布特征,以贵州省花溪区30年生和45年生马尾松人工林为研究对象,采用土钻法获取0~40 cm土层细根,分析两林龄不同土壤深度细根生物量、形态结构及养分变化特征.结果显示30和45年生马尾松林0~40 cm土层细根总生物量分别为367.24和396.13 g·m^(-2),比根长分别为4.40和4.69 m·g^(-1),比表面积分别为131.92和133.43 cm^2·g^(-1).细根生物量、细根形态结构和细根养分变化在两个林龄间差异不显著;但是细根生物量、形态结构受到土壤深度的影响.0~10 cm土层细根根长密度、根表面积密度显著大于其他3层;0~10 cm土层的细根分叉数显著大于30~40 cm土层;马尾松林细根集中分布在0~10 cm土层.表明贵州高原山地丘陵区马尾松从近熟林到成熟林阶段细根分布趋于稳定,集中分布在0~10 cm土层.

In order to clarify the vertical distribution characteristics of fine roots(diameter≤2 mm)of Pinus massoniana forests at different age stages in Guizhou Plateau,30(near mature)and 45(mature)year-old P.massoniana plantations in the hilly and mountainous areas of Huaxi District,Guiyang City were studied.Fine roots in 0-40 cm soil layer were obtained by soil auger,and growth indexes,including fine root biomass,morphological structure and nutrient characteristics of different soil layers were analyzed.The results showed that total biomass of fine roots for 30 and 45 year-old plantations was 367.24 and 396.13 g·m-2,respectively.Specific root length reached 4.40 and 4.69 m·g-1,respectively for the near-mature and mature forests,with specific surface area being 131.92 and 133.43 cm2·g-1.Fine root biomass,morphology and nutrient composition were not significantly different between the 2 forest ages.Fine root biomass and morphology were significantly affected by soil depth.Root length density and root surface area density in 0-10 cm soil layer were significantly higher than those in 10-20,20-30,30-40 cm soil layers.Fine root bifurcation number in 0-10 cm soil layer was significantly higher than that in 30-40 cm soil layer.It can be concluded that the vertical distribution of the fine roots of near-mature and mature P.massoniana forests tend to be stable and mainly concentrated in 0-10 cm soil layer.