沙地樟子松根系分布及土壤、微生物生态化学计量特征

Root Distribution and Soil and Microbial Ecological Stoichiometry Characteristics of Pinus sylvestris in Sandy Land

以辽西北沙地60 a樟子松过熟林为研究对象,分析樟子松细根生物量、土壤与微生物生物量C、N、P及其生态化学计量特征在不同的水平距离和垂直土层深度的分布变化规律及相关性,旨在探讨各指标之间的关系,旨在为该地区的樟子松林培育和经营提供一定的理论依据。结果表明,辽西北沙地樟子松过熟林细根主要分布在距树干基部0~2.0 m的水平区域,深度为0~40 cm的土层中,冠幅以外区域细根分布较少;土壤、微生物生物量C、N、P垂直分布特征均受樟子松细根的影响,土壤C、N、P主要分布在0~40 cm土层,具有明显表聚性。相关分析结果表明,樟子松细根生物量与土壤全氮、土壤微生物生物量碳、土壤微生物生物量氮呈极显著正相关,与土壤的有机碳含量呈显著正相关。综上可知,樟子松过熟林表现为浅根性,主要从0~40 cm土层吸收养分,养分限制类型为氮限制;为延缓过熟林的衰退,在森林经营过程中,可在远树干区域合理引入固氮植物,并适当采取禁牧(封育)等措施。

In this study,60 a overmature forest of Pinus sylvestris var.mongolica plantation as the research object in the sandy land of northwestern Liaoning was taken,the distribution and correlation of Pinus sylvestris var.mongolica fine root biomass,soil and microbial biomass of C,N,and P and the ecological stoichiometric characteristics at different horizontal distances and vertical soil depths were analyzed to explore the related relationships between the indexes and provide a theoretical basis for the cultivation and management of Pinus sylvestris var.mongolica plantation in this area.The results showed that the fine roots of Pinus sylvestris var.mongolica overmature forest in the sandy land of northwestern Liaoning were mainly distributed in the horizontal area of 0-2.0 m from the base of the tree trunk and with a depth of 0-40 cm.The fine roots were less distributed outside the crown.The vertical distribution characteristics of soil and microbial biomass C,N,and P were affected by their fine roots.Soil C,N,and P were mainly distributed in the 0-40 cm soil layer with obvious surface aggregation.The correlation analysis showed that the biomass of Pinus sylvestris fine roots was extremely significantly positively correlated with soil total nitrogen,soil microbial biomass carbon,soil microbial biomass nitrogen,and was significantly positively correlated with soil organic carbon content.In summary,the overmature forest of Pinus sylvestris exhibited shallow roots,which mainly absorbed nutrients from the 0-40 cm soil layer,and the nutrient restriction type was N restriction.In order to delay the decline of overmature forest,in the process of forest management,nitrogen-fixing plants in the distant trunk area could be reasonably introduced,and appropriate measures such as prohibition of grazing(enclosure)could be conducted.