黄竹侵入对热带林地土壤养分的影响

通过对黄竹林的入侵、定居和扩散3个演替阶段土壤养分状况的分析，探讨了黄竹林的形成和发展对土壤养分的影响。结果表明：随着黄竹群落演替的进行，土壤有机质和全氮的质量分数逐渐减小。土壤全氮质量分数分布类似于有机质，并呈现正相关性（r＝0．8586，n1＝n2＝51）；随着群落演替的进行，黄竹林地表土层的全磷质量分数和有效性磷的质量分数逐渐增大，有效性磷素的缺乏是植物生长的限制因子之一；黄竹林地土壤钾的质量分数和有效性钾的质量分数以侵入期至定居期下降 的幅度最大，此后到扩散期又稍有回升；土壤有效性钙和镁的质量分数随着演替的进行而增加。

Variation of Soil Nutrient Dynamics under Dendrocalamus membranaceus Foest in Xishuangbanna

The soil nutrient contents and dynamics in different growth stages (invasion, habitation, spread) of Dendrocalamus membranaceus forest in Xishuangbanna were analyzed. The results showed that the content of soil organic matter and total N decreased with the development of Dendrocalamus membranaceus communities, and the correlation ( r =0.858 6, n 1= n 2=51) between organic matter and total nitrogen in the soil was positive; the content of total P and available P in topsoil and available Ca, Mg in soil increased with the ages of the Dendrocalamus membranaceus communities; the content of total K and available K decreased greatly from invasion stage to habitation stage, then increased in spread stage; the difference of total K content in soil is insignificant in all growth stages of the Dendrocalamus membranaceus communities, and there is a lack of available P in soil under bamboo forest.