摘要
【目的】比较2个密度杨树人工林的土壤团聚体和固碳差异,揭示其土壤固碳过程,为制定有效的可持续人工林经营措施提供理论基础。【方法】采集高密度(400株·hm^(-2))和低密度(278株·hm^(-2))杨树人工林(16年)表层土壤,利用最适湿度干筛法将土壤团聚体分为小(<0.25 mm)、中(0.25~2 mm)、大(>2 mm)粒级,测定各粒级中活性、慢性和惰性有机碳含量及其矿化速率。【结果】与低密度相比,高密度杨树人工林土壤的中、小团聚体组成占比显著提升,大团聚体组成占比降低,分别为1.06%、21.92%和77.02%。2个密度杨树人工林的各粒级土壤团聚体的有机碳组分均存在显著差异,其中高密度人工林土壤各粒级活性和慢性有机碳含量较高,而惰性有机碳含量在<0.25 mm和0.25~2 mm粒级中较低。室内培养试验发现,与低密度人工林相比,高密度人工林土壤各粒级团聚体的碳矿化速率在整个培养阶段普遍较低,说明保守的土壤微生物碳代谢策略是高密度林土壤有机碳积累的关键。林分密度对土壤团聚体粒级分布及活性和慢性有机碳含量有显著影响,而对土壤惰性有机碳含量影响不显著;其中高密度林的土壤密度降低导致了活性和慢性有机碳含量的积累。【结论】合理调节林分密度是影响人工林土壤团聚体形成和有机碳组分的重要营林措施。高密度杨树人工林土壤的密度降低和保守的土壤碳代谢能力将有利于土壤碳固存。
【Objective】Compare the differences in soil aggregation and carbon sequestration between two poplar plantation forests to reveal the basic process of carbon sequestration in plantation forests,thereby providing a theoretical basis for sustainable forest management.【Method】We collected the surface soil of high density(400 plants·hm^(−2))and low density(278 plants·hm^(−2))poplar plantation(16 a),and classified soil aggregates into<0.25 mm,0.25–2 mm,and>2 mm particle levels by the optimal moisture-dry sieving method,studying the content of active,slow and passive organic carbon,and the rate of soil carbon mineralization in each particle level.【Result】Compared with the low-density poplar plantation forests,the composition of soil aggregates in the high-density poplar plantation forests had a higher proportion of<0.25 mm and 0.25–2 mm particle sizes and a lower proportion of>2 mm particle sizes,respectively 1.06%,21.92%and 77.02%.There were significant differences in the organic carbon fractions in soil aggregates at all particle levels among poplar plantations of different densities.Among them,active and slow organic carbon were higher in all particle levels of high-density plantation forest soil,while passive organic carbon was lower in<0.25 mm and 0.25–2 mm particle levels.The indoor incubation experiments revealed that soil carbon mineralization rates at all particle levels were generally lower in high-density plantation forests compared to low-density plantation forests throughout the incubation stage,suggesting that conservative soil microbial carbon metabolism strategies are the key to soil organic carbon accumulation in high-density plantation forests.Further analysis revealed that stand density had a significant effect on soil aggregate particle size distribution and active and slow organic carbon, but not on soil passive organic carbon;in which the reduction of soil density under high-density stands led to the accumulation of active and slow organic carbon content. 【Conclusion】In summary, reasonable regulation of stand density is an important silvicultural measure that affects soil aggregate formation and organic carbon fractions in plantation forests. Reduced soil bulk density and conserved soil carbon metabolism capacity in high-density poplar plantation forests would be favorable for soil carbon sequestration.
作者
杨豆
刘超华
李凤巧
唐罗忠
田野
方升佐
李孝刚
Yang Dou;Liu Chaohua;Li Fengqiao;Tang Luozhong;Tian Ye;Fang Shengzuo;Li Xiaogang(College of Ecology and Environment Nanjing Forestry University,Nanjing 210037;College of Forestry and GrasslandNanjing Forestry University,Nanjing 210037)
出处
《林业科学》
EI
CAS
2024年第10期21-28,共8页
Scientia Silvae Sinicae
基金
国家重点研发计划项目“美洲黑杨大径级工业资源材精准高效培育技术研究”(2021YFD2201202)
国家重点研发计划项目“杨树摄取氮素的根系-微生物互作机制及靶向调控技术”(2022YFD2201900)
国家自然科学基金项目“外生菌根真菌-细菌互作调控杨树干旱适应性的微生态过程及机制”(32430069)。
关键词
人工林
营林措施
土壤团聚体
土壤碳汇
plantation
forest managements
soil aggregates
soil carbon sinks
作者简介
通讯作者:李孝刚。
