C,N,P Stoichiometry And Seasonal Variation Of Different Natural Secondary Forest Ecosystem In Ziwuling Forest Area

In order to explore the carbon(C),nitrogen(N),phosphorus(P)stoichiometry and seasonal variation of different natural secondary forest ecosystem in Ziwuling forest area and understand the nutrient distribution pattern and nutrient supply,we chose Piuns tabuliformis and Quercus wutaishanica natural secondary forests in Ziwuling and subsequently investigated and compared their C,N and P stoichiometry of leaf,stem,root,litter and soil from April to October by field investigations and laboratory analyses.The C,N,P stoichiometriy,seasonal variation,and the correlation of leaf-litter-soil were studied to provide theoretical basis for the restoration and management of natural forest resources.The main results are as follows:1)The C,N,P stoichiometry of leaf,stem and root and their seasonal variation.The C content and C:N of leaf and stem of Piuns tabuliformis were significantly higher than that of Quercus wutaishanica(P < 0.05);N content and N:P were significantly lower than that of Quercus wutaishanica(P < 0.05),which means that Piuns tabuliformis has a higher defense capability against adversity,however,it is less efficient for N utilization.The root P content was significantly higher(P < 0.05)and C:P was significantly lower than that of Quercus wutaishanica(P < 0.05).The C content of two species of stem and root were higher in the early stage and late stage of growth,and lower in the exuberant growth period.The variation of N,P content of Piuns tabuliformis were smaller.The leaf N and P content of Quercus wutaishanica were higher in the early stage of growth and lower at the end of growth.The stem N and P content of the two species were generally lower in the initial stage of growth and higher at the end of growth,which reflected the nutrient transfer of the leaf before senescence.The C,N and P stoichiometry of leaf were mainly affected by the interaction between tree species and month.The C,N and P stoichiometry of stem and root are mainly affected by species.2)The C,N,P stoichiometry of litter and their seasonal variation.The C content of litters of Piuns tabuliformis was significantly higher and the N content was significantly lower than that of Quercus wutaishanica(P < 0.05),therefore,C:N was significantly higher than that of Quercus wutaishanica(P < 0.05),which reflected that the decomposition rate and nutrient release rate were lower of Piuns tabuliformis.The C,N and P stoichiometry showed obvious seasonal variation patterns,which were related to the quality and decomposition rate of the matrix in different months.In the analysis of variation sources,C:P of litter which can be the index of decomposition rate has been mainly influenced by months.On the one hand,it may be the change of litter quality.On the other hand,temperature and precipitation affected the decomposition rate of litter.3)The C,N,P stoichiometry of soil and their seasonal variation.The C content of soil in each layer of Pinus tabuliformis and C: N and C: P were significantly lower than that of Quercus wutaishanica(P < 0.05).The variation of soil C,N and P contents of Pinus tabuliformis forest were similar between layers.However,soil C,N,P content variation of Quercus wutaishanica forest were not,which reflected the effect of tree species on soil nutrients.In the analysis of variation sources,the C content of soil is mainly affected by tree species,and C: N is mainly affected by the interaction between tree species and month.There were no significant effects on P content and N: P.4)The correlation of C,N,P stoichiometriy of leaf-litter-soil.The nutrient of C and N content showed: leaf > litter > soil.The litter N was significantly related to the soil(P < 0.05),and the correlation between the components of the Quercus wutaishanica was weaker than that of the Pinus tabuliformis.