鹞落坪4种典型植被类型土壤活性碳、氮特征比较

为了探讨不同植被类型土壤活性碳氮的差异特征，系统分析了不同植被类型土壤活性碳氮水平。以安徽省鹞落坪自然保护区内常绿阔叶林（EBF）、常绿落叶阔叶混交林（EDBF）、落叶阔叶林（DBF）和常绿针叶林（ECF）4种典型植被类型为对象，研究其土壤微生物量碳（MBC）、氮（MBN）和溶解性有机碳（DOC）、氮（DON）的含量。结果表明：用热水浸提的土壤DON和DOC含量分别是用KC1浸提的1．5～2．8倍。不同植被类型下，用热水和KC1溶液浸提的DOC和DON含量的大小顺序均为：DBF〉EDBF〉EBF〉ECF；DONKCI的含量与DONhw的含量之间均不存在显著的相关关系，土壤潜在性可矿化氮（PMN）含量与DONhw含量存在显著的正相关关系（r=0．85，P〈0．05），与DONKa含量不存在显著的相关关系，说明用热水浸提的DON含量比KCI溶液浸提的DON含量能更好地指示土壤活性有机氮库。土壤MBC的变化范围在136．45-297．23mg／kg，土壤MBN的变化范围在16．33～37．11mg／kg，4种林型土壤MBCXMBN的特征均为：DBF〉EBF〉EDBF〉ECF。相关性分析显示，土壤MBC与DOC之间以及土壤MBN与DON之间的相关性达显著或极显著水平，说明土壤MBC、MBN、DOC和DON之间有密切联系，且不同植被类型下土壤活性碳氮来源不同是DOC、DON与MBC、MBN~]关性差异的主要原因。

The Characteristics Comparison of Soil Active Organic Carbon and Nitrogen of 4 Kinds of Vegetation Types in Yaoluoping

In order to explore the difference characteristics of soil active organic carbon and nitrogen in different vegetation types, the author systematically analyzed the different vegetation types in the level of soil active organic carbon and nitrogen. This field study was conducted at Yaoluoping Nature Reserve, Anhui Province. In order to determine the concentrations of soil microbial biomass carbon （MBC）, microbial biomass nitrogen （MBN）, dissolved organic carbon （DOC）, and dissolved organic nitrogen （DON） under 4 different vegetations, including evergreen broad-leaved forest （EBF）, evergreen broad-leaved and deciduous broad-leaved mixed forests （EDBF）, deciduous broad-leaved forests （DBF） and evergreen coniferous forests （ECF）. The results showed that hot water extracted 1.5-2.8 times more soil DOC and DON than 2 mol/L KC1.The pool sizes of DOC and DON were measured by hot water and 2 mol/L KC1 extraction were in the order of DBF〉EDBF〉EBF〉ECF under 4 different vegetations; The amounts of DON in 2 mol/L KC1 extracts were not significantly correlated with those in hot water extracts. The DON in hot water extracts was significantly related to potential mineralizable N （PMN） （r =0.85, P〈0.05）, while there was no such relationship present between the PMN and the DON in KC1 extract. This indicated that the DON in hot water extracts might better indicator of soil active organic N pool. Soil MBC and MBN concentrations were 136.45-297.23 mg/kg, and 16.33- 37.11 mg/kg, respectively. 4 forests in soil MBC and MBN were characterized by DBF〉EBF〉EDBF〉ECF. There were significant positive correlations between MBC, MBN and DOC, DON, indicating the close relationships between MBC, MBN and DOC, DON and the main reason of this distinction was the diverse source in active organic carbon and nitrogen under different vegetation.