沙地樟子松人工林叶凋落物的分解与养分释放

Decomposition and nutrient release of leaf litter in Pinus sylvestris var.mongolica plantations

凋落物的分解和养分释放是森林生态系统养分循环的关键过程,但樟子松人工固沙林叶凋落物的分解和养分释放机理仍不清楚。文中以辽宁省章古台地区的樟子松叶凋落物为研究对象,选择标准地收集叶凋落物,采用原位分解法研究樟子松叶凋落物的分解和养分释放。结果表明:樟子松叶凋落物的年失重率为27.48%,分解常数为0.209,凋落物分解50%的时间为3.32年,分解95%的时间为14.33年。在一年分解过程中,凋落物碳(C)、纤维素和木质素含量减少,氮(N)、磷(P)含量增加;分解前60d,失重率主要受纤维素、木质素含量调控,随后主要受C含量、C/N和C/P调控。经过360d的分解,养分释放率表现为C>纤维素>木质素,N、P表现为净累积。分解过程中C释放主要受失重率、剩余凋落物P含量、纤维素和木质素含量的调控;N累积主要受剩余凋落物C含量、初期基质N含量和P素累积的调控;P累积主要受初期基质N、P含量的调控。建议在沙地樟子松人工林抚育管理时,适当添加N、P肥,促进沙地樟子松生态系统的养分循环。

The decomposition and nutrient release of litter are the key processes of nutrient cycling in forest ecosystems,but the decomposition and nutrient release mechanism of leaf litter of Pinus sylvestris var.mongolica plantations is still unclear.In this paper,the leaf litters of selected standards in Pinus sylvestris var.mongolica plantations in Zhanggutai area,Liaoning Province were collected,and the in-situ decomposition method was used to study the decomposition and nutrient release of leaf litters.The results showed that the annual weight loss rate of litter was 27.48%,the decomposition constant was 0.209,the time that required for decomposing 50%of the leaf litter was 3.32 years,and that required for decomposing 95%of the leaf litter was 14.33 years.In the process of one-year decomposition,carbon(C),cellulose and lignin decreased,while nitrogen(N)and phosphorus(P)increased.Before 60 days of decomposition,the weight loss rate was mainly regulated by the contents of cellulose and lignin.Subsequently,it was mainly dominated by C content,C/N and C/P.After 360 days of decomposition,the nutrient release rate was C>cellulose>lignin,N and P showed net accumulation.During decomposition,C release was mainly regulated by the weight loss rate,the P content in the remaining litter,and cellulose and lignin contents.N accumulation is mainly regulated by the C content in residual litter,the N content in the initial matrix and the accumulation of P.P accumulation is mainly regulated by the content of N and P in the initial matrix.It is recommended that we should add appropriate N and P fertilizers to promote the nutrient cycle in P.sylvestris in plantations management.