Carbon storage and turnover, and respiratory activity, in the litter and soil of an old-growth southern beech (Nothofagus) forest
Carbon storage and turnover, and respiratory activity, in the litter and soil of an old-growth southern beech (Nothofagus) forest
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古老的南方山毛榉森林的凋落物和土壤中的碳储存和周转以及呼吸活动
DOI：
10.1016/0038-0717(93)90016-5
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发表时间：
1993
影响因子：
9.7
通讯作者：
F. Kelliher
中科院分区：
文献类型：
--
作者：
K. Tate;D. J. Ross;B. J. O'brien;F. Kelliher
对新西兰低洼原始山毛榉（Nothofagus）森林土壤和凋落物碳库、碳周转及其与森林地面呼吸活动的关系进行了研究。虽然土壤在空间上存在差异，但它们的形态、化学和某些物理性质都具有spodosol的特征。两个剖面代表土壤的范围，通过水平分析：C，14C和一些化学和物理性质。在站点最具代表性的土壤中，细凋落物和矿质土的C分别为ca3.0和15.8 kg m−2。根据一个简单的指数模型，每年从森林地面呼吸约0.65 kg CO2-C m−2，该模型是由室内技术测量的co2外排与土壤温温值之间的关系。温度主要控制着凋落物和土壤产生的二氧化碳，因为场地全年都有充足的降雨。利用“炸弹”放射性碳模型根据14c的分布估算了凋落物向大气和土壤中C的年转移量，以及C在凋落物和土壤中的平均停留时间（ca12年）。土壤碳的一个主要来源是根周转量，这是基于精细凋落物测量和总碳输入模型得出的。根系周转和木屑共占土壤总碳输入量的64%，总碳输入量为0.8kg m−2yr−1。根据根C分配总量与凋落物之间的关系，通过实验估计，活根呼吸占森林地面呼吸的23%。假定稳态条件下，年土壤C循环存在ca0.35 kg cm - 2的不平衡。直接测量和模型相结合估算碳通量的误差，以及对森林地面呼吸的低估，可能是造成这种不平衡的原因。模拟的土壤C的平均停留时间从76年到207年不等，这是由于土壤上层23厘米处存在的“惰性有机质”的数量差别很大。长期的树木翻倒历史最有可能是土壤表面附近顽固碳集中的原因，这可能解释了新西兰山毛榉下土壤的碳储存时间比原生草地下土壤的碳储存时间更长。
Soil and litter carbon pools and turnover, and their relationship to forest floor respiratory activity, were estimated in a lowland old-growth beech (Nothofagus) forest in New Zealand. Although the soils varied spatially over the site, their morphological, chemical and some physical properties were characteristic of spodosols. Two profiles representing the range of soils were analysed by horizon for: C,14C and a number of chemical and physical properties. C in the fine litter and mineral soil, in the most representative soil at the site, wasca3.0 and 15.8 kg m−2respectively. About 0.65 kg CO2-C m−2was respired annually from the forest floor, based on a simple exponential model relating CO2efflux measured by a chamber technique, and soil temperature values. Temperature mainly controlled CO2production by litter and soil because the site was well supplied with rainfall throughout the year. Annual transfers of C from the litter to the atmosphere and the soil, and mean residence times for C in the litter (ca12 yr) and soils were estimated from the distribution of14C using a ‘bomb’ radiocarbon model. A major source of soil C was root turnover, based on fine litterfall measurements and modelling of total C input. Root turnover and woody debris together represented 64% of the total C input ofca0.8kg m−2yr−1to the soil. Live root respiration, estimated experimentally and from a relationship between total root C allocation and litterfall, wasca23% of the forest floor respiration. An imbalance ofca0.35 kg C m−2was observed in the annual soil C cycle, assuming steady-state conditions. Errors in estimating C fluxes from a combination of direct measurements and models, and underestimation of forest floor respiration, were probably responsible for this imbalance. Modelled mean residence times for soil C ranged from 76 to 207 yr, and resulted from widely different amounts of ‘inert organic matter’ being present in the upper 23 cm of the soils. A long history of tree overturn is the most likely cause of this concentration of recalcitrant C near the soil surface, and may explain the longer C storage time of soils developed under beech in New Zealand compared to those developed under native grassland.