高寒沙区中间锦鸡儿人工林细根动态及其周转

Biomass Dynamics and Turnover of Fine Roots of Caragana intermedia Plantations in Alpine Sandy Land

通过对青海省治沙试验站3 a、5 a、10 a、16 a和30 a生的中间锦鸡儿(Caragana intermedia Kuang et H. C.Fu)人工林细根生物量的测定分析,了解其细根生物量的垂直分布和动态变化特征以及周转速率。结果表明:①中间锦鸡儿人工林约41%的活细根和39%的死细根分布在0~20 cm的土层,38%的活细根和死细根分布在20~40 cm的土层,21%的活细根和23%的死细根分布在40~60 cm的土层。②细根生物量表现出明显的季节动态性,活细根生物量峰值出现在6月和8月或者6月和9月,8月或9月达到最大值;死细根生物量峰值出现8月和9月,也是8月或9月达到最大值。③不同林龄人工林细根周转速率分别为:0. 53、0. 66、0. 56、0. 73、0. 78次·a^-1。④细根生物量和周转率均随林龄增大而增加,随土层加深而减小。

The determination and analysis of the biomass of fine roots of Caragana intermedia plantations with 3,5,10,16 and 30 tree-ages at the Qinghai Province Sand Control Experimental Station were carried out. The purposes of the study were to accurately understand the vertical distribution,dynamic variation and turnover rate of the biomass of fine roots of C. intermedia plantations. The results showed that about 41% living fine roots and 39% dead fine roots of C. intermedia plantations were distributed in soil layer 0-20 cm in depth,38% living fine roots and dead fine roots were distributed in soil layer 20-40 cm in depth,and 21% living fine roots and 23% dead fine roots were distributed in soil layer 40-60 cm in depth. There was an obvious seasonal dynamic change of the biomass of fine roots,and the peak biomass of living fine roots appeared in June and August or June and September,and its maximum occurred in August or September;the peak biomass of dead fine roots appeared in August and September,and its maximum also occurred in August or September. The turnover rates of C. intermedia plantations with different tree-ages were 0. 53,0. 66,0. 56,0. 73 and 0. 78 times·a^-1. The biomass and turnover rate of fine roots of C. intermedia plantations increased with the increase of tree-age,but decreased with the increase of soil depth.