不同人工林生态系统林地土壤质量评价

利用定位研究方法，综合比较了第2代连栽杉木纯林、杉木与阔叶树混交林以及阔叶纯林3种人工林生态系统对林地土壤质量的影响．结果表明，与连栽杉木纯林相比，在杉阔混交和阔叶树轮栽两种经营模式下，土壤养分含量增加，物理性状改善，土壤生物活性提高．利用土壤质量评价体系在对土壤功能评价的基础上，直观评价了3种经营模式的土壤质量状况．在研究区内，杉木与阔叶树混交以及阔叶树轮栽的水分有效性、养分有效性和根系适宜性以及最终的土壤质量指数均处于中等水平，而连栽杉木林的水分有效性、养分有效性和根系适宜性较差，土壤质量指数处于较低水平．总有机C、阳离子交换量和微生物生物量C与其它土壤理化性质和生物学性质之间明显相关，可将其作为研究区土壤质量的指示指标；土壤微生物生物量C、N、P与土壤总有机C、土壤全N、土壤全P含量之间也存在较好的相关性。

Siol quality assessment of forest stand in different plantation ecosystems

After a clear-cutting of the first generation Cunninghamia lanceolata plantation in 1982,three plantation ecosystems,pure Michelia macclurei stand (PMS),pure Chinese-fir stand (PCS) and their mixed stand,were established in spring 1983,and their effects on soil characteristics were evaluated by measuring some soil physical,chemical,microbiological and biochemical parameters.After 20 years' plantation,all test indices showed differences among different forest management models.Both PMS and MCM had a favorable effect on soil fertility maintenance.Soil quality assessment showed that some soil functions,e.g.,water availability,nutrient availability,root suitability and soil quality index were all in a moderate level under the mixed and pure PMS stands,whereas in a relatively lower level under successive PCS stand.The results also showed that there existed close correlations between soil total organic C (TOC),cation exchange capacity (CEC),microbial biomass-C (C mic) and other soil physical,chemical and biological indices.Therefore,TOC,CEC and C mic could be used as the indicators in assessing soil quality in this study area.In addition,there were also positive correlations between soil microbial biomass-C and TOC,soil microbial biomass-N and total N,and soil microbial biomass-P and total P in the present study.