入侵植物薇甘菊对土壤养分和酶活性的影响

Effects of Mikania micrantha invasion on soil nutrient contents and enzyme activities

为揭示外来植物入侵薇甘菊对土壤生态的影响机制,研究了薇甘菊不同入侵程度样地土壤养分和土壤酶活性变化规律。结果显示,与裸土和本地植物土壤相比,薇甘菊入侵显著提高了有机质、全氮、全钾、硝态氮、铵态氮、有效磷、速效钾、脲酶和磷酸酶的含量,而全磷和蔗糖酶的较本地植物区有所下降,且随着入侵程度增强趋势更为明显。重度入侵区w(土壤有机质)最高达108.01 g.kg-1,分别是裸土区、单一当地植物区和混生当地植物土的6.3、3.1、2.0倍,重度入侵区w(铵态氮)最高达23.76 mg.kg-1,分别较裸土、单一当地植物土和混生当地植物土增加了92%、50%和52%,而重度入侵区的脲酶含量为4.01,显著高于当地植物区,比裸土区增加了83%。薇甘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,形成其不可替代的优势种群。

In this study, the change patterns of soil nutrient contents and enzyme activities in different Mikania micrantha invaded areas were analyzed for understanding the impacts of alien invasive plant on soil ecosystem. Compared to non-vegetation and native-plant soils, it was most noticeable that Mikania micrantha increased soil organic carbon, total N, total K, NO3-N, NH4-N, available P, available K content and the activities of urase and phosphatase. But lower contents of total P and activities of sucrase, and the change trends of these parameters became more obvious with increasing invasion level. Organic carbon content in the heavily-invaded soil was 108.01 g.kgl, which was 6.3, 3.1 and 2 times as that in the non-vegetation, single-native-plant soils and multi-native-plants, respectively. The contents of NH4-N in the heavily-invaded soil was 23.76 mg.kg1, which were increased by 92%, 50% and 52% than that in the non-vegetation, single-native-plant soils and multi-native-plants, respectively.while the activities of urase in the heavily-invaded soil was 4.01, which was significantly higher than that in native-plant soils and increased by 83% than that in the non-vegetation soils, respectively. It was suggested that Mikania micrantha induced the changes of soil nutrient contents and enzyme activities, and in return, endowed the superiority ofMikania micrantha in its inter-specific competition.