Abstract:

In the Naban River watershed,five different economic forest lands(tea groves,sugarcane lands,rubber groves,pitaya lands and banana lands) and primary forest soils that are used as reference were taken as research objects to explore the characteristics of soil eco-stoichiometry after the primary forest in Naban River watershed in Xishuangbanna was converted into economic forest land.This article will study the soil nutrient changes and stoichiometric characteristics.The results show that the contents of soil organic C,N and P are inclined to decrease with increasing soil depth.The primary forests and perennial rubber forests of six different forest types that are less disturbed by human activities contain relatively lower C,N and P.The C/N in soils in different forest types presents a spindle-type distribution with little contents in the surface and substratum while more in the middle;the C/P of pitaya land is the lowest among different forest types,while the C/P of sugarcane and banana soils is relatively high;primary forest and rubber forest present a low N/P ratio,while sugarcane field presents a higher N/P ratio.Correlation analysis shows that there is a very significant positive correlation between N,P,organic C and N/P(P<0.01).The C/N,N and P is significantly correlative (P<0.05);the correlation between C and C/P is significant (P<0.01),and the correlation between N/P is significant(P<0.05).

Key words: different economic woodlands, soil nutrients, eco-stoichiometric characteristics