论文部分内容阅读
不同林分密度下叶凋落物基质物质、养分动态及分解速率研究对人工林密度管理具有重要的实践意义。2009—2011年应用分解网袋法对不同林分密度等级下叶凋落物3年间的分解速率、养分动态及化学成分的变化进行测定分析,结果表明:1)凋落物叶失重率年际变化为倒“V”型变化;高密度林分Ⅰ失重率在第3年与其它林分密度存在极显著差异,说明密度对凋落物分解的影响有时间效应。2)分解速率所体现出的林分密度调控效应与失重率及木质素与氮的比值在试验的3年内均保持负相关的变化规律,故木质素/氮、失重率可作为凋落物分解速率的预测指标;可用灰分含量作为周转时间的指示指标。3)N,K的养分动态为释放—固定循环模式;P为平衡波动—固定模式,Mg为持续固定模式,Ca表现出单一的释放—固定变化模式。
The study on leaf litter substance, nutrient dynamics and decomposition rate under different stand densities has important practical significance for plantation density management. The results showed that: 1) The annual change rate of litter leaf weight loss rate was (1) the change rate of leaf litter decomposition rate, nutrient content and chemical composition in different stand density classes during 2009-2011 In the first year, the weight loss rate of high density forest Ⅰ was significantly different from that of other forest stands, indicating that the effect of density on litter decomposition had a time effect. 2) The decomposition rate of the stand density control effect and weight loss rate and lignin and nitrogen ratio in the test of 3 years to maintain a negative correlation between the variation, so lignin / nitrogen, weight loss rate can be used as litter decomposition rate Of the forecast index; available ash content as an indicator of turnaround time. 3) Nutrient dynamics of N and K are in the mode of release-fixed cycle; P is the equilibrium-fluctuating-fixed mode; Mg is the persistent mode; and Ca shows a single mode of release-fixation.