马缨丹入侵对草坪土壤养分特征的影响

 研究了外来入侵物种马缨丹对草坪不同入侵程度条件下土壤理化性质和土壤蛋白酶、脲酶及磷酸酶活性的变化，分析了马缨丹入侵对土壤养分影响在其入侵过程中的意义。结果表明：马缨丹的入侵显著提高了根际土壤有机质、全氮、全钾、NH₄⁺-N、NO₃^--N、和速效钾的含量，导致土壤碱化，但显著降低了土壤全磷和速效磷的含量；马缨丹种群根际土壤蛋白酶、脲酶和磷酸酶活性均显著高于裸露地和非入侵草坪草多花黑麦草与白花三叶草植物群落。土壤酶活性与土壤有机质、全氮、全钾、NH₄⁺-N、NO₃^--N、速效钾的含量和土壤pH极显著正相关，而与土壤全磷和速效磷的含量极显著负相关，土壤酶活性与土壤理化性质存在显著相关关系。马缨丹入侵改变了根际土壤酶活性和土壤养分的供求平衡，这种改变可能有利于马缨丹的生长竞争并对草坪草的生长产生抑制作用。为马缨丹入侵的生态影响和其成功入侵的原因提供了试验依据，为阐明马缨丹入侵机制奠定理论基础。

Effects of Lantana camara Invasion on Lawn Soil Nutrient Properties

The effects of invasive plant Lantana camara on soil properties and soil enzymatic activities at different habitats of lawn along the invaded process of L.camara were studied. The experimental design was set up based on using following 4 sites denoting invasive progress of L.camara: naked field site (CK), non invaded site, newly invaded site and heavily invaded site. The soil samples were collected at rhizosphere zones (about 0~20cm) on January 5, 2008. The rhizosphere soil pH, organic carbon, total N and K, NH₄⁺-N、NO₃^-- N and available K contents in heavily invaded site showed the highest value, the second in newly invaded site and the lowest in CK. As what mentioned above, the rhizosphere soil enzymatic activities among different sites showed as follows: CK>non-invaded site>new invaded site>heavily invaded site. There were significant positive correlations between soil enzymatic activities and soil pH, organic carbon, total N and K, NH₄⁺-N、NO₃^--N available K, but significant negative correlations between soil enzymatic activities and soil total P and available P. These results indicated that the invasive weed L.camara could alter soil enzymatic activities and the trade offs of nutrients supply and demand, which might facilitate itself growth but inhibit other plant growth. This study indicated that alien invasion plant caused huge impacts on native habitats.