皖南山区人工林土壤化学性质的空间分异及影响因子

森林土壤性状的空间分异会影响森林生态系统生产力和生态恢复方向。由于受到人类活动干扰,人工林土壤化学性质的变化特征一直不清晰。为探明皖南山区人工林土壤化学性质随林分类型、海拔和土层的变化特征,2016年10月在安徽省东至县梅城林场选择不同林分、不同海拔的6块样地,分层采集0～20 cm和20～40 cm的土样,测定了土壤酸碱度、电导率、总有机碳、活性有机碳、可溶性有机碳和全氮等化学性质。结果表明:1)该人工林地的土壤化学性质主要由林分类型主导,不同林分类型的土壤电导率和总有机碳等指标存在显著差别,针叶林的土壤养分含量显著高于其他(P0.05);2)林分类型对土壤化学性质的影响与植物群落多样性无关,主要是通过林木种类(即群落的优势种群)发挥作用的;3)海拔对人工林的土壤化学性质也有显著影响(P0.05),海拔越高土壤性状越好;4)随剖面深度增加,林分类型对土壤特性的影响将增强,海拔的作用会减弱。综上,调控林分类型是改善皖南山区人工林土壤化学性质的有效措施,种植针叶林能有效提升表层土壤养分含量,增加亚表层土壤活性碳的比例。

Spatial variations and influence factors of soil chemical properties in plantation forests in south of Anhui Province

Spatial variations of soil characteristics in forest directly always determine the forest productivity and the approach to ecological restoration. However, in plantation forests that have been suffered from many disturbances due to human activities, spatial distribution of soil physical and chemical properties are still unclear. To examine the status of soil properties in different plantation forests, altitude and soil depth in southern mountainous area in Anhui Province, we sampled soil from six forests in Meichen forestry station at Dongzhi County in October 2016, and measured its pH, Ec, TOC, LOC, DOC and TN at the soil depth of 0-20 cm and 20-40 cm. The results were as follows: 1) The soil chemical characteristics of artificial forest in Meicheng forestry station were mainly affected by forest types, and the order of soil fertility was generally ranked as coniferous forest > hard broad-leaved forest > broad-leaved mixed forest; 2) The dominant species in forest rather than plant community diversity drive the influences of forests on soil chemical properties; 3) Altitude also has significant impact on the chemical properties of forest soil; 4) The influence of plantation types on soil properties would strengthen the increasing of profile depth, while the effect of altitude would not. Taken together, regulation of forest types are the effective approach to improving the soil nutrient status of the Mecheng artificial forestry station, and planting coniferous forests can promote soil nutrients and carbon sequestration capacity at surface profile, as well as optimize the composition of SOC at sub-surface profile.