寒温带林区不同林型土壤酶活性和微生物生物量的变化特征

Variation Characteristics of Soil Enzyme Activity and Microbial Biomass under Different Forest Types in Cold Temperate Forest Region

在大兴安岭高寒区(122°42′14″~123°18′5″E、51°17′42″~51°56′31″N)黑龙江呼中国家级自然保护区内,以大兴安岭寒温带林区海拔400~1100 m的杜香-落叶松(Ledum palustre-Larix dahurica)林、杜鹃-落叶松(Rhododendron dauricum-Larix dahurica)林、杜鹃-白桦(Rhododendron dauricum-Betula platyphylla)林、偃松(Pinus pumila)林的土壤为研究对象;采用主成分提取因子,分析4种林型2个土层(h)0<h≤5 cm和5 cm<h≤20 cm土层的化学指标、土壤脲酶、蛋白酶、天门冬酰胺酶、土壤微生物生物量碳和氮的变化特征。结果表明:4种林型中,0<h≤5 cm土层的脲酶、蛋白酶活性,5 cm<h≤20 cm土层的微生物生物量碳,变化特征值由大到小依次为杜香-落叶松林、杜鹃-落叶松林、杜鹃-白桦林、偃松林;0<h≤5 cm土层微生物生物量碳,5 cm<h≤20 cm土层的脲酶活性、蛋白酶活性、天门冬酰胺酶活性以及微生物生物量氮,变化特征值由大到小依次为杜香-落叶松林、杜鹃-白桦林、杜鹃-落叶松林、偃松林。在垂直剖面,4种林型的全氮质量分数、总有机碳质量分数、碱解氮质量分数、全磷质量分数、土壤酶活性以及微生物生物量,随土层深度的增加而降低,而pH和全钾质量分数升高。全氮、总有机碳、碱解氮、全磷,对土壤酶活性和微生物生物量产生了重要影响。寒温带林区不同林型土壤酶活性和微生物生物量的变化特征,因林型、海拔以及土层的差异,导致土壤酶活性和微生物生物量的差异,2个土层均表现为:随着海拔的升高,土壤酶活性和微生物生物量降低;随着土层的加深,土壤酶活性和微生物生物量降低。

In the Heilongjiang Huzhong National Nature Reserve in the alpine region of the Daxing’an Mountains(122°42′14″-123°18′5″E,51°17′42″-51°56′31″N),the soil was studied from the Daxing’an Mountains cold-temperate forest zone at the elevations of 400-1100 m for the Ledum palustre-Larix dahurica forest,Rhododendron dauricum-Larix dahurica forest,Rhododendron dauricum-Betula platyphylla forest and Pinus pumila forest.The principal component extraction factors were used to analyze the soils of the four forest types.The chemical indicators,soil urease,protease,asparaginase,soil microbial biomass carbon and nitrogen in the soil layers of 0<h≤5 cm and 5 cm<h≤20 cm were analyzed using principal component extraction factors.In the four forest types,the characteristic values of urease and protease activities in the 0<h≤5 cm soil layer and microbial biomass carbon in the 5 cm<h≤20 cm soil layer were in the descending order of Ledum palustre-Larix dahurica,Rhododendron dauricum-Larix dahurica,Rhododendron dauricum-Betula platyphylla and Pinus pumila forest.The variation characteristics of soil microbial biomass carbon of 0-5 cm,urease and protease activities of 5-20 cm soil layer,asparaginase activity and microbial biomass nitrogen were in the descending order of Ledum palustre-Larix dahurica,Rhododendron dauricum-Betula platyphylla,Rhododendron dauricum-Larix dahurica,and Pinus pumila.In the vertical profile,total nitrogen content,total organic carbon content,alkali-dissolved nitrogen content,total phosphorus content,soil enzyme activity,and microbial biomass of the soils of the four forest types decreased with increasing soil depth,while pH and total potassium content increased.Total nitrogen,total organic carbon,alkaline decomposed nitrogen,and total phosphorus,exerted important effects on soil enzyme activity and microbial biomass.The variation characteristics of soil enzyme activity and microbial biomass in different forest types in the cold temperate forest zone were characterized by differences in forest type,elevation,and soil layer,resulting in differences in soil enzyme activity and microbial biomass,which decreased with increasing elevation in both soil layers,and decreased with deepening of the soil layer.