长白山次生针阔混交林叶凋落物中有机物分解与碳、氮和磷释放的关系

Decomposition of litter organic matter and its relations to C,N and P release in secondary conifer and broadleaf mixed forest in Changbai Mountains

采用分解袋法,研究了长白山次生针阔混交林内9种树种叶凋落物34个月的分解过程.结果表明:在次生针阔混交林中,不同树种叶凋落物的初始N和P浓度存在很大差异,叶凋落物分解速率(k)与初始N浓度和C/N显著相关.有机物剩余百分率与C剩余百分率呈显著的线性正相关关系,与N和P剩余百分率之间呈显著的二项式回归关系.N和P剩余百分率在初期阶段随有机物分解而增加,达到峰值后逐渐降低.随着有机物剩余百分率的下降,C/N和C/P均呈逐渐降低趋势,各种叶凋落物之间C/N和C/P的差异逐渐减小,分解末期分别趋近于23和350.随有机物剩余百分率的降低,N/P变化不明显,当有机物剩余百分率低于25%时,不同树种叶凋落物之间N/P差异显著下降.有机物剩余百分率可用来预测C、N和P的剩余百分率.

By using litterbag method, the decomposition processes of 9 types of foliar litter in secondary conifer and broadleaf mixed forest in Changbai Mountains were assessed during a period of 34 months. The initial N and P concentrations varied greatly among the litters, and there were significant relationships between litter decomposition constant （k） and initial N concentration and C/ N. The percent organic matter remaining had a significant linear correlation with percent C remaining, and a significant polynomial correlation with percent N and P remaining. The percent N and P remaining increased with the decomposition of organic matter in its initial decomposition phase, but decreased gradually in the latter decomposition phase. C/N and C/P declined with the decrease of percent organic matter remaining, and the differences in C/N or C/P among litter types decreased, being approached to 23 and 350, respectively by the end of the study. During organic matter decomposition, N/P did not change greatly, and the differences in N/P between litter types declined when the percent organic matter remaining was below 25%. Our study showed that percent of C ,N and P mass remaining can be predicted by percent of organic matter mass remaining.