【摘要】 通过对地处澜沧江上游滇西北山区大理洱源县炼铁乡的6种不同土地利用类型土壤氮含量与土壤酶活性变化进行分析,探讨他们的变化及其相互关系,为退化山地土壤的恢复与可持续利用提供理论依据。结果表明:(1)不同土地利用类型下土壤氮含量、土壤酶活性均存在较大差异。旱冬瓜林地聚积了丰富的养分,土壤生态环境良好,土壤氮含量、土壤酶活性均大于其他土地利用类型。不同土地利用类型土壤氮含量、土壤酶活性的差异,能比较客观地反映出退化程度的不同。(2)无论是哪一种土地利用类型均表现出土壤氮含量越高,土壤酶活性越高。在氮素循环转化的过程中,氮素营养逐渐衰减,土壤酶活性也随之降低,土壤发生不同程度的退化。(3)从土壤垂直剖面上看,土壤氮含量与土壤酶活性均随土层加深呈明显下降趋势,可以看出土地利用类型、人为活动对土壤氮含量与土壤酶活性的影响主要集中在表层(A层)。(4)土壤氮含量与土壤酶活性存在一定相关。土壤氮含量和土壤酶活性的降低均会导致土壤退化程度的加深。更多还原

【Abstract】 Nitrogen content and enzyme activity under six different kinds of soil utilization types in Eryuan County in Northwest Yunnan mountainous area of the upper reaches of Lancang River were studied,the changes in soil nitrogen and enzyme activities and the interrelationship between these two parameters in these lands were examined in order to restore the deteriorated soils in the mountainous region and provide the theory basis on sustainable land uses.The results showed that:(1) Soil nitrogen content and enzyme activities were different in different land utilization types,which reflected the different degree of soil degradation.Rich nutrients were accumulated in Alnus nepalensis forest land,and the soil ecological environment were good,namely soil nitrogen content and enzyme activity were greater than other land utilization types;(2) Under all kinds of land utilization types,the higher is the soil nitrogen content,the greater is the enzyme activity.In the process of nitrogen cycling,the soil enzyme activity decreased with the nitrogen decayed and soil also degraded in various degrees;(3) From the vertical profile of the soil,the land utilization and human activities affected surface layers in these lands since the soil nitrogen content and enzyme activity decreased with the depth of soil profile;(4) Soil nitrogen content had certain correlation with soil enzyme activity.The degree of soil degradation became serious along with decrease in soil nitrogen content and the soil enzyme activity.更多还原