Soil Ecological Stoichiometric Characteristics of Eucalyptsu urophylla×E. grandis in Different Ages on the Leizhou Peninsula

PurposeThe study explored the changes of soil organic C, total N, total P, total K and the stoichiometric characteristics of the Eucalyptus urophylla×E. grandis fast-growing forest with different ages (1, 2, 3, 5, 7 years) on the Leizhou Peninsula to provide theoretical basis for scientific management.

MethodThree sample plots were set in E. urophylla×E. grandis plantations with different ages. The five points sampling method was used for stratification and sampling. The concentration of carbon (C), nitrogen (N), phosphorus (P) and potassium (K) and the stoichiometric characteristics was analyzed in different plantations and soil depths.

ResultSoil C content (0~20 cm) increased signifcantly with the raising of stand age, while the total N content had minor differences. The total P and K content of 5-years old forest were lower or significantly lower (P<0.05) than other eucalyptus plantations. Soil organic C and total N in the five different plantations decreased with the increase of soil depth, the total P and total K content had smaller variability among the soil depth. The C/N and C/P had an increasing tendency with the increase of age while P/K, C/K and N/K decreased firstly, then increased in 5 and 7-years old; there was no significant difference in soil N/P among the different ages. Correlation analyses showed that: the soil organic C had significantly positive correlation with total N and total P (P<0.01). Correlations among soil total N, total P and total K were insignificant (P>0.05).

ConclusionThe circulation rate of the soil C, N of the E. urophylla×E. grandis in the middle and young age on the Leizhou Peninsula was comparatively slow. The mineralization rate of soil organic matter decreased with age increasing. Stands growth was limited by N.