蒋家沟泥石流频发区不同植被类型与土壤养分及酶的关系

The effects of vegetation type on soil nutrients and enzymes in Jiangjia Gulley with frequent debris flow

不同植被类型区内的植物群落结构与土壤养分、土壤酶活性具有耦合关系,为揭示泥石流频发区土壤养分及酶活性对地上植被的响应规律,运用野外调查和实验室分析相结合的方法,研究云南蒋家沟泥石流频发区扭黄茅草地(Heteropogon contortus)、坡柳灌丛(Salix myrtillacea)以及9年、15年和26年新银合欢纯林5种典型样地群落结构、土壤养分、土壤酶活性及其关系.结果显示:植物多样性指数排序为坡柳灌丛>扭黄茅草地>26年新银合欢纯林>15年新银合欢纯林>9年新银合欢纯林;扭黄茅草地和坡柳灌丛的土壤有机质(OM)显著大于不同林龄的新银合欢纯林(P<0.05);扭黄茅草地和坡柳灌丛的C:P和N:P大于不同林龄新银合欢纯林;植物多样性指数(辛普森指数、香农-维纳指数)与土壤有机质、蔗糖酶(Invertase)呈现显著的正相关(P<0.05);且有机质和蔗糖酶呈现极显著的正相关(P<0.01).本研究表明,多样性指数高的地上植被群落有助于泥石流频发区积累土壤肥力,可一定程度地提高土壤生物活性.

Plant community structure, soil nutrients and soil enzyme activity have a coupling relationship in relation to the vegetation types. This research aimed to find the relationship between structure of plant community and soil nutrients and enzymes in an area with frequent debris flow. We took as the main research object of 5 typical vegetation types in the Jiangjia Gulley including Heteropogon contortus, Salix myrtillacea and Leucaena leucocephala of 9 years, 15 years and 26 years. We analyzed the characteristics and correlation of plant diversity with soil nutrients and soil enzyme activity by methods of field investigation and laboratory analysis. The results showed a sequence of plant diversity as Salix myrtillacea 〉 Heteropogon contortus 〉 26-year Leucaena leucocephala 〉 15-year Leucaena leucocephala 〉 9-year Leucaena leucocephala. The contents of the soil organic matter, the C：N and C：P were all higher in Heteropogon contortus and Salix myrtillacea than in Leucaena leucocephala of all three ages （P 〈 0.05）. The Simpson and Shannon-Wiener plant diversity indices showed a significant positive correlation with soil organic matter and Invertase （P 〈 0.05）. Finally, the organic matter showed an extremely significant positive correlation with Invertase （P 〈 0.01）. The results indicated that higher plant diversity index in different vegetation communities can help the accumulation of soil fertility and can improve soil biological activity in areas with frequent debris flow.