杨梅根系和土壤微生物量碳、氮、磷生态化学计量随林龄的变化

利用空间代替时间的方法,研究了浙江省仙居县3、9、14、21年生根系和土壤微生物量碳(C)、氮(N)、磷(P)含量及化学计量比.结果表明,杨梅根系C、C:N在不同林龄间没有显著差异;随着林龄的增加,根系N、P含量降低,而C:P、N:P则增大;21年生杨梅根系N含量显著低于3年生(P<0.05),磷含量显著低于其他林龄(...

The variation of ecological stoichiometry characteristics of carbon,nitrogen and phosphorus in root system of Myrica rubra and its soil microbial biomass with different stand ages

In this study,we used the spatial sequence instead of time successional sequence to explore the ecological stoichiometry of carbon(C),nitrogen(N),and phosphorus(P)in root system of Myrica rubra and its soil microbial biomass with different stand-age groups (3y, 9y, 14y and 21y) in Xianju County, Zhejiang Province. The results indicated that there was no significant difference in the C and C: N of Myrica rubra in root system among different stand-age groups. With the increase of cultivation ages, the content of N, P in roots decreased, while the ratio values of C: P and N: P increased. The content of N in 21-year-old root was significantly lower than that of 3-year-old (P<0.05), and the content of P in root was significantly lower than that of other stand-age groups (P<0.05). The ratio values of C: N and N: P in roots of 21-year-old Myrica rubra were significantly lower than those of other stand-age groups (P<0.05). Based on the variation of ratio values of N: P under different stand-age groups, the P element became a more obviously limiting element for the growth of Myrica rubra. With the increase of cultivation ages, the contents of soil microbial biomass carbon (MBC), nitrogen (MBN) and phosphorus (MBP), and the ratio values of MBC: MBN and MBC: MBP decreased firstly and then increased, while the ratio values of MBN: MBP had an upward trend. The content of MBC and the ratio value of MBC: MBN in the 3-year-old treatment was significantly higher than other age groups(P<0.05), and the MBN, MBP contents were significantly higher than those of treatment with 9-year-old (P<0.05). The ratio of MBC: MBP in the 9-year-old treatment was significantly lower than other ages groups (P<0.05). The ration value of MBN: MBP of 0-10cm soil in the 3-year-old treatment was significantly lower than other age groups, while the ratio values of MBN: MBP of 10-30 cm soil in the 21-year-old treatment was significantly higher than other ages groups. Based on the variation of N: P values, the limiting element is N at the young growth stage, while P element is the limiting element for the growth of Myrica rubra after 14 years.