本文系统地研究了27a生杉木观光木混交林和杉木纯林群落细根(<2mm)的生物量、净生产力和年周转率。结果表明,混交林和纯林群落活细根现存量分别为3.872和3.315t·hm-2,活细根现存量变化呈双峰型,在3月和9月出现两次高峰;死细根现存量为1.509和1.269t·hm-2,数量变化呈现单谷型,在5月或3月出现最低值;细根净生产力分别为4.124和3.528t·hm-2a-1,分别占各自群落净第一性生产力的22.9%和20.9%;细根年死亡量分别为2.119和1.894t·hm-2,相当于各自群落地上部分凋落物量的31.4%和27.8%;细根周转率分别为1.07和1.06,观光木、混交林杉木、纯林杉木的细根周转速率依次降低,而林下植被层细根周转率高于乔木层。表明细根周转是群落有机质归还的重要途径,对维持和改良地力有重要作用。
Studies on biomass, net productivity and annual turnover rate of fine roots in mixed forest of Cunninghamia lanceolata and Tsoongiodendron odorum and in pure stand of Cunninghamia lanceolata at 27 years old were carried out. The existing amount of living fine roots in both stands were up to 3.872 and 3.315 t·hm-2, and their seasonal changes showed two peaks in March and September, and those of dead fine roots amounted to 1.509 and 1.269 t·hm-2, being lowest in May or March. The net productivity of fine roots in both stands totaled to 4.124 and 3 528 t·hm-2a-1, accounted for 22.9% and 20.9% of total net primary productivity of community, respectively. In both stands, annual mortality of fine roots were 2.119 and 1.894 t·hm-2, respectively, amounted 31.4% and 27.8% of annual aboveground litterfall. Annual turnover rate of fine roots was 1.07 in mixed stand and 1.06 in pure stand, which decreased successively from Tsoongiodendron odorum, Cunninghamia lanceolata in mixed forest to the pure stand, and that of undergrowth were higher than that of tree stralum in both stands. It was concluded that annual turnover of fine roots was an important way for organic matter in communities returning to forest floor.
全 文 ：