A decomposition experiment for a year was conducted at Jiulingtou Forest Farm, Zigui County, Hubei Province, China to examine the decomposition dynamics of fine roots with different diameters (<0.5, 0.5-1 and 1-2 mm) and its main affecting factors for Pinus massoniana. The results showed that the decomposition rate decreased with the increasing root diameter. The annual decomposition rates for fine roots with diameters <0.5, 0.5-1 and 1-2 mm were 34.0%, 28.0% and 25.7%, respectively. The decomposition rate of <1 mm fine root decreased along time, and 1-2 mm fine root increased first and then decreased. In the fine root decomposition process, N, P and Ca concentrations increased along time, and K concentration decreased firstly, then increased, and then decreased along time. Fine root decomposition rate was significantly related to initial chemical composition (N, P, K, Ca, C/N and C/P) of fine roots. Ca concentration in fine root and soil temperature were the major factors affecting fine root decomposition.
在三峡库区秭归县九岭头林场马尾松人工林进行一年的细根分解试验,研究马尾松直径<0.5、0.5～1和1～2 mm细根的分解动态及其影响因素.结果表明: 细根分解速率随直径增大而减小,直径<0.5、0.5～1和1～2 mm细根年分解率分别为34.0%、28.0% 和25.7%.直径<1 mm细根分解速率随时间增加而逐渐减小,直径1～2 mm细根分解速率随时间增加先逐渐增加再减小.在细根分解过程中,N、P和Ca浓度随时间增加而增加,K浓度呈先降低后上升再下降的趋势.细根分解速率与细根初始N、P、K和Ca浓度,以及C/N、C/P均显著相关,细根Ca浓度和土壤温度是影响细根分解的主导因子.
Keywords: Pinus massoniana; fine root decomposition; nutrient.