中文摘要：

研究了低强度火对马尾松次生林物种多样性的影响及不同火强度干扰下土壤化学性质5a内的动态变化规律。结果表明，火干扰样地内物种和植物个体数目均高出对照样地，分别为对照样地的118％和108％；对照样地内物种多样性指数Gleason、Shannon-Wiener指数、Simpson指数和Pielou均匀度分别为3．01、11．21、10．30和0．74，火干扰样地对应的指数分别为12．13、5．61、26．13和0．84，树冠层、灌木层、草本层的均匀度分别由0．71、0．83、0．55提高到0．81、0．89、0．72。除有机质外，火干扰对土壤阴离子交换（CEC）、全N、碱解N、全P、全K和速效K的影响持续期不长，大多在2a左右恢复到火烧前的水平；火干扰强度对Ⅰ层有机质、速效P含量和Ⅱ层速效P含量的影响极显著（p〈0．05），不同时间点Ⅰ层土壤有机质（SOM）和Ⅱ层速效P含量随火干扰影响的趋势有明显的差异（p〈0．05），分别拟合了火干扰强度对SOM全P、碱解N和速效P含量（火灾后第一年）的影响模型。

英文摘要：

Changes of species diversity and the dynamic rules of soil chemical properties in the stand of Pinus massoniana under fire disturbance with different intensities from 2001 to 2005 were investigated. The results showed that type and number of plant species in P. massoniana stand under fire disturbance were 18% and 8% respectively higher than those in control stand. The Gleason （ICL） index, the Shannon-Wiener（Isw）index, the Simpson （Isp） index and the Pielou（J） of the were 10.30, 3.01, 11.21 and 0.74 respectively in the control stand , but those in the fire disturbed stand were 12.13, 5.61,26.13 and 0.84 respectively. The values of J in crown canopy, shrub layer and herb layer increased from 0.71, 0.83, 0.55 to 0.81, 0.89, 0.72 respectively. Except for organic matters, the duration of the influence of fire disturbance on soil CEC, total N, hydrolyzable N, total P, total K and available K was not long. Usually, these indices would be restored in 2 years to the levels before fire disturbance. The influences on organic matter, available P in the first layer and available P in the second layers were extremely remarkable（p〈0.05）. The influence tendency on organic matter in the first layer and available P in the second layer of different time was obviously（p〈0.05）, then the models fire disturbance on SOM, total P, available N, available P （first year after fire） were fitted respectively separately under different intensities of fire.