格氏栲天然林及人工林和杉木人工林生活叶-凋落叶-土壤生态化学计量特征

Ecological Stoichiometric Characteristic of Leaf-Litter-Soil in Natural and Planted Forests of Castanopsis kawakamii and Cunninghamia lanceolata

通过采用野外调查与室内分析相结合的方法,测定格氏栲天然林、格氏栲人工林和杉木人工林生活叶、凋落叶以及土壤(0~40 cm)C、N、P含量,并探讨3种林分生活叶、凋落叶和土壤的化学计量特征。结果表明:1)3种林分C、N、P含量均为生活叶>凋落叶>土壤,3种林分生活叶和凋落叶C、N、P含量差异均不显著,土壤C含量为格氏栲天然林显著高于2种人工林,而N、P含量差异不显著;2)3种林分C∶N、C∶P、N∶P均表现为凋落叶>生活叶>土壤,格氏栲天然林和人工林生活叶N∶P均>16,而杉木人工林生活叶14<N∶P<16,生活叶C∶N为杉木人工林最高,凋落叶C∶N为格氏栲人工林最低,凋落叶、土壤C∶P为杉木人工林最低;3)随土层深度的增加,3种林分土壤C、N、P含量逐渐减少,而C∶N、C∶P、N∶P变化不大;4)3种林分N含量和C∶N在生活叶和凋落叶之间均呈显著负相关(P<0.05)。格氏栲天然林改为人工林后土壤C含量显著降低,格氏栲天然林和人工林生长受N限制,杉木人工林生长受N、P限制,且土壤P的有效性高。研究结果有助于了解不同林分的限制性元素,为该研究区格氏栲和杉木的养分管理提供科学依据。

The contents of carbon,nitrogen,and phosphorus in in the leaves,leaf litters,and soils(0-40 cm)of natural and planted forests of Castanopsis kawakamii and planted Cunninghamia lanceolata were examined by combining field investigation and indoor measurement to explore the ecological stoichiometric characteristics of leaf-litter-soil interactions in three forests.The results showed that:1)the concentrations of C,N and P in three forests were in the order of leaf>litter>soil,no significant differences in C,N and P contents were found in the leaves and litter of three forests,the soil C content in natural forest of C.kawakamii was significantly higher than those in other two forests,but N and P contents were not significantly different.2)The ratios of C∶N,C∶P and N∶P in three forests were in the order of litter>leaf>soil;the ratios of N∶P in the living leaves of natural and planted C.kawakamii forest were above>16,and between 14 and 16 in planted C.lanceolata forest;the ratios of C∶N of the leaves was the highest in planted C.lanceolata forest,the C∶N of the litter was the lowest in natural C.kawakamii;the C∶P of the litter and soil were the lowest in planted C.lanceolata forest.3)The concentrations of soil C,N and P in three forests decreased gradually with the increase of soil depth,soil C∶N,C∶P and N∶P were in relative steady state.4)The N contents and C∶N in the leaves showed significant positive correlation with the litters in three forests.These results revealed that after natural C.kawakamii forest changed to planted one,soil C content decreased significantly,the growths of natural and planted forests of C.kawakamii were restricted by N,the growth of planted C.lanceolata forest was restricted by N and P,and soil P was highly effective.The findings in the study could contribute to understand the limiting elements of different forests and provide scientific guidance for nutrient management of C.kawakamii and C.lanceolata forests in this study area.