黄顶菊入侵对土壤养分和酶活性的影响

Effects of Flaveria bidentis invasion on soil nutrient contents and enzyme activities

比较了外来植物黄顶菊不同入侵程度土壤养分和土壤酶活性变化规律,探讨了外来植物入侵对土壤生态的影响机制。结果表明,与裸土和本地植物土壤相比,黄顶菊入侵显著提高了有机质、全氮、硝态氮和铵态氮的含量,而全磷和速效磷的含量有所下降,且随着入侵程度增强趋势更为明显。重度入侵土壤有机质较本地植物土壤提高5.7%,全氮提高23.4%;而重度入侵土壤全磷含量只有本地植物的85%,土壤速效磷含量则下降了50%。黄顶菊重度入侵土壤和轻度入侵土壤脲酶含量分别为0.04和0.03mg.g-1.24h-1,均显著高于裸土和本地植物土壤,土壤磷酸酶活性变化规律与之类似,而多酚氧化酶无明显的变化。黄顶菊入侵可以改变土壤养分和土壤酶活性,创造对自身生长有利的土壤环境,并借此增强其竞争能力,实现种群的进一步扩张。

Aimed to approach the effects of alien plant invasion on soil ecosystem,this paper studied the change patterns of soil nutrient contents and enzyme activities under different levels of Flaveria bidentis invasion.Comparing with non-vegetated and native plant soils,the F.bidentis invaded soil had higher contents of soil organic carbon,total nitrogen,NO-3-N,and NH＋4-N but lower contents of soil total and available phosphorus,and the change trends of these parameters became more obvious with increasing invasion level.Comparing with those in native plant soil,the organic carbon and total nitrogen contents in F.bidentis heavily invaded soil increased by 5.7% and 23.4%,while the total and available phosphorus contents decreased by 85% and 50%,respectively.The urease activity in F.bidentis heavily and lightly invaded soils was 0.04 and 0.03 mg·g-1·24 h-1,respectively,being higher than that in non-vegetated and native plant soils,the phosphatase activity changed with same manner,while the polyphenol oxidase activity had less change.It was suggested that F.bidentis invasion induced the changes of soil nutrient contents and enzyme activities,and in return,endowed the superiority of F.bidentis in its inter-specific competition.