川西亚高山岷江冷杉林土壤生物肥力特征研究

Biological fertility characteristics of soil in sub-alpine Abies faxoniana forests in Western Sichuan

【目的】以川西亚高山岷江冷杉林为研究对象,研究该区表层土壤微生物种群数量、酶活性以及与之相关的土壤养分季节动态等土壤生物肥力特征。【方法】在川西亚高山岷江冷杉林中设置样地,2011-08中旬在样地上、中、下坡位放置分解袋,分别于2011年9月、11月和2012年3月、5月、7月中旬随机取回部分分解袋,测定其中土壤养分、微生物数量和酶活性,并进行相关分析和主成分分析。【结果】林地土壤微生物数量、酶活性和养分含量季节差异显著,在3种微生物中以细菌数量最多;细菌和真菌数量,蔗糖酶和过氧化氢酶活性,有机质、全氮、全钾、全磷、速效氮和有效磷含量7月最高,放线菌数量、脲酶活性9月最高。相关分析表明,细菌数量与全钾、有机质、全磷、速效氮、有效磷含量呈显著正相关,真菌数量与有机质、全氮、速效钾含量呈显著正相关,放线菌数量与全磷、速效氮、有效磷含量呈显著正相关,脲酶、蔗糖酶、过氧化氢酶活性与有机质、全氮、全钾、速效氮、速效钾含量呈显著正相关;主成分分析表明,第1主成分贡献率为49.766%,主要综合了蔗糖酶、全钾、全磷、真菌的信息。【结论】川西亚高山岷江冷杉林土壤微生物数量、酶活性及土壤养分三者之间相互影响,共同反映土壤生物肥力特征。

[Objective] The biological fertility seasonal dynamics of microorganism quantities, enzyme activities and nutrients contents of A1 layer soil in sub-alpine fir forests soil in Western Sichuan were stud- ied. [Method] Sample plots were set up in subalpine Abies faxoniana in Western Sichuan. Litter bags were put on the up,middle and down positions of slopes in the middle of August 2011 ,and then bags were ran- domly retrieved in the middle of September and November 2011 ,and March,May and July 2012. Soil micro- organism quantities ,enzyme activities and nutrients contents were determined,and correlation analysis and principal component analysis were conducted to analyze the measured variables. [Result] Seasonal varia- tions in soil microorganism quantities and enzyme activities were significant. The quantity o{ bacteria was the highest among the three measured microorganisms. The maximum values of bacteria and {ungi quanti- ties, activities of sucrose and catalase, and contents of organic matter, total N, total K, total P, available N and available P were measured in July,while the maximum values of actinomycetes quantity and urease ac- tivity appeared in September. Furthermore, positive correlations among bacteria and total K, organic mat- ter, total P, available N, and available P were observed, and positive correlations among fungus and organicmatter, total N,and available K were significant. Correlations among actinomycetes and total P, available N, and available P were significant, and there were significant positive correlations among the enzyme activ- ities of urease, sucrose and catalase and contents of organic matter,total N, total K,available N and availa- ble K. Principal component analysis showed that the first component containing sucrose, total K, total P, and fungus contributed to 49. 766 %. [Conclusion] Soil microbial quantities, enzyme activities and nutrients contents of subalpine A. faxoniana in Western Sichuan interacted with each other,and they could be used as indicators for soil biological fertility.