山西太岳山不同针叶纯林及混交林土壤有机碳库的变异性

Variability of Soil Organic Carbon Pool in Different Coniferous Pure Forests and Mixed Forests in Taiyue Mountain,Shanxi Province

为研究不同针叶林型土壤有机碳及其碳库管理指数变化特征,以山西太岳山林区油松(Pinus tabuliformis)林、华北落叶松(Larix gmelinii var.principis-rupprechtii)林、油松和华北落叶松混交林3种人工林为研究对象,测定了各森林群落的根系生物量、土壤理化性质,分析不同林型土壤理化性质及碳库管理指数的变化特征。结果表明:土壤有机碳质量分数、全氮质量分数、土壤含水率、β-葡萄糖苷酶活性、酸性磷酸酶活性等均在油松落叶松混交林中出现最大值。3种林型的土壤有机碳库中,稳定有机碳的质量分数最高,约占总有机碳的80%以上。在0<h≤10 cm土层中,油松林土壤碳库管理指数显著低于落叶松林和油松落叶松混交林(P<0.05),前者分别比后两者低22.32%、21.69%。相关性分析及结构方程模型(SEM)表明,林分类型的转变对土壤含水率、土壤酶活性有显著正向影响(P<0.05),根系生物量显著促进了土壤养分及土壤酶活性的增加,土壤养分及根系生物量对土壤碳库管理指数产生显著正向影响(P<0.05)。油松和华北落叶松混交可以提高土壤养分质量分数,增强土壤微生物活性,有利于土壤碳库管理指数和碳库质量的提高。

In order to study the characteristics of soil organic carbon and its carbon storage management index in different coniferous forest types,three artificial forests including Pinus tabuliformis forest,Larix gmelinii var.principis-rupprechtii forest,and mixed forest of P.tabuliformis and L.gmelinii var.principis-rupprechtii in Taiyue Mountain Forest Area,Shanxi Province,were selected as the research objects.The root biomass and soil physicochemical properties of each forest community were measured,and the changes in soil physicochemical properties and carbon pool management index of different forest types were analyzed.The results showed that the soil organic carbon content,total nitrogen content,soil moisture content,β-glucosidase activity,and acid phosphatase activity were highest in the mixed forest of P.tabuliformis and L.gmelinii var.principis-rupprechtii.In the soil organic carbon pool of the three forest types,the content of stable organic carbon was highest,accounting for more than 80% of the total organic carbon.In the 0<h≤10 cm soil layer,the carbon pool management index of P.tabuliformis forest was significantly lower than that of L.gmelinii var.principis-rupprechtii forest and mixed forest(P<0.05),and it was 22.32% and 21.69% lower than the latter two,respectively.Correlation analysis and structural equation model(SEM) showed that the conversion of forest types had a significant positive effect on soil moisture content and soil enzyme activity(P<0.05),and root biomass significantly promoted the increase of soil nutrients and soil enzyme activity.Soil nutrients and root biomass had a significant positive effect on the carbon pool management index of soil(P<0.05).The mixed forest of P.tabuliformis and L.gmelinii var.principis-rupprechtii can improve the content of soil nutrients,enhance soil microbial activity,and contribute to the improvement of the carbon pool management index and carbon pool quality of soil.