云冷杉林土壤酶活性与土壤养分的研究

对不同生长状况云冷杉林土壤酶活性在不同土层进行比较,并对土壤酶与土壤养分及与林下植物的关系进行分析。结果表明：不同土层的土壤酶活性对云冷杉林死亡程度响应不同,0-15 cm土壤酶活性变化最为显著,随土层深度的增加,酶活性减小,且对云冷杉的死亡响应程度减弱;5种土壤酶活性对云冷杉死亡程度响应表现不一,脲酶和过氧化氢酶活性随死亡程度的加大对云冷杉死亡率响应较最大,而转化酶、磷酸酶及多酚氧化酶活性随云冷杉死亡程度的增加下降较小;土壤有机质的含量对云冷杉林死亡程度的响应较大,对照样地有机质含量与重度及极重度死亡样地间呈极显著相关关系（P〈0.01）,5种酶活性均与有机质、速效K含量极显著正相关（P〈0.01）;云冷杉林死亡率增加,其林下植物多样性指数亦呈增加趋势,随着云冷杉林死亡程度的增加林下灌木层多样性增加,而林下草本层的多样性先增加后减少;林下植物Shannon-Wiener指数和Pielou指数与土壤多酚氧化酶活性的相关性最强,其次是过氧化氢酶。

Soil enzymes activities and soil nutrient of Picea and Abies forest

Soil enzymes activities were compared on different soil depth in Picea and Abies forest with different growth conditions.We studied the relation between different soil enzymes activities,and the different Picea and Abies forest in relation to soil nutrient and plant diversity.The results showed that the five soil enzymes activity varied decrease with increasing soil depth.And the soil enzymes in the top layer(0-15 cm) were enhanced distinctly compared with in the layers middle(15-35 cm) and subsoil(35-55 cm).Also,the five enzymes in the topsoil(0-15 cm) were affected differently by different level of deaths of Picea and Abies forest,showing that soil urease and catalase were highest response to different level of deaths of Picea and Abies forest,while invertase and phosphatase and polyphenol oxidase were response to slight.The response of soil organic matter to the death of Picea and Abies forest were most apparent.There were significant correlations between soil organic matter of contrast sample plot and intense death sample plot and super intense death sample plot(P<0.01).It was concluded that increasing the mortality of Picea and Abies forest was benefit to the development of diversity indices of the undergrowth,diversity of the undergrowth in shrub layer increased with increasing the death degree of Picea and Abies forest, but diversity of the undergrowth in herbaceous layer was initially increased then decreased.Correlation studies have shown that the most relevant exists among undergrownth plants Shannon-Wiener index and Pielou index and the soil polyphenol oxidase activity,followed by catalase.