森林类型对土壤有机质、微生物生物量及酶活性的影响

以澳大利亚南昆士兰州典型森林类型——湿地松、南洋杉和贝壳杉林为对象,开展土壤可溶性有机碳和氮(SOC和SON)、微生物生物量碳和氮(MBC和MBN),以及土壤酶活性的研究,剖析森林类型对土壤质量的影响.结果表明:不同林型土壤SOC、SON含量分别在552 ～1154 mg·kg-1和20.11～57.32mg·kg-1;MBC、MBN分别在42～149 mg·kg-1和7～35 mg·kg-1.MBC、MBN之间呈显著相关.土壤几丁质酶、酸性磷酸酶、碱性磷酸酶和β-葡萄糖苷酶的活性分别为2.96 ～7.63、16.5 ～29.6、0.79 ～ 3.42和3.71 ～9.93 μg ·g-1·h-1,亮氨酸氨肽酶活性为0.18～0.46 μg·g-1·d-1.不同林型土壤SOC含量,以及土壤几丁质酶和亮氨酸氨肽酶活性为湿地松林、南洋杉林、贝壳杉林依次降低;而SON含量为南洋杉林＞贝壳杉林＞湿地松林,且南洋杉林的SON含量显著(P＜0.05)高于湿地松林;MBC和MBN以及碱性磷酸酶活性为贝壳杉林＞湿地松林＞南洋杉林;酸性磷酸酶和β-葡萄糖苷酶活性为湿地松林＞贝壳杉林＞南洋杉林.在土壤生物代谢因子中,MBC、MBN、SON和亮氨酸氨肽酶对不同森林类型土壤影响较大.

Effects of forest type on soil organic matter, microbial biomass, and enzyme activities

Taking the typical forest types Pinus elliottii var. elliotttii, Araucaria cunninghamii, and Agathis australis in southern Queensland of Australia as test objects, an investigation was made on the soil soluble organic carbon (SOC) and nitrogen (SON), microbial biomass C (MBC) and N (MBN), and enzyme activities, aimed to understand the effects of forest type on soil quality. In the three forests, soil SOC content was 552-1154 mg kg(-1), soil SON content was 20.11-57.32 mg kg(-1), soil MBC was 42-149 mg kg(-1), soil MBN was 7-35 mg kg(-1), soil chitinase (CAS) activity was 2.96-7.63 microg g(-1) h(-1), soil leucine aminopeptidase (LAP) activity was 0.18-0.46 microg g(-1) d(-1), soil acid phosphatase (ACP) activity was 16.5-29.6 microg g(-1) h(-1), soil alkaline phosphatase (AKP) activity was 0.79-3.42 microg g(-1) h(-1), and soil beta-glucosidase (BG) activity was 3.71-9.93 microg g(-1) h(-1). There was a significant correlation between soil MBC and MBN. Soil SOC content and soil CAS and LAP activities decreased in the order of P. elliottii > A. cunninghamii > A. australis, soil SON content decreased in the order of A. cunninghamii > A. australis > P. elliottii and was significantly higher in A. cunninghamii than in P. elliottii forest (P < 0.05), soil MBC and MBN and AKP activity decreased in the order of A. australis > P. elliottii > A. cunninghamii, and soil ACP and BG activities decreased in the order of P. elliottii > A. australis > A. cunninghamii. Among the test soil biochemical factors, soil MBC, MBN, SON, and LAP had greater effects on the soil quality under the test forest types.