Soil carbon and belowground carbon balance of a short-rotation coppice: assessments from three different approaches.
Soil carbon and belowground carbon balance of a short-rotation coppice: assessments from three different approaches.
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DOI：
10.1111/gcbb.12369
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发表时间：
2017-02
期刊：
影响因子：
--
通讯作者：
Ceulemans R
中科院分区：
文献类型：
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作者：
Berhongaray G;Verlinden MS;Broeckx LS;Janssens IA;Ceulemans R
不同土地利用过渡期间土壤碳（C）通量的不确定性是进一步部署多年生生物能源作物需要解决的问题。建立了一个大规模的白杨和杨柳短轮伐矮林（SRC）基地，以研究耕地和牧场向生物能源的土地利用过渡。在为期4年的研究中，对土壤C库、土壤CO2、CH 4、溶解性有机碳（DOC）和挥发性有机物的输出通量以及凋落物和根系的输入通量进行了沿着环境参数的测定。三种方法被用来估计土壤C的变化。土壤中最大的碳库是土壤有机碳库，在SRC四年后从10.9 kg C m − 2增加到13.9 kg C m−2。地下木质生物量（粗根）是第二大碳库，其次是细根（Fr）。每年落叶代表最大的C输入到土壤中，其次是杂草和Fr。第一次收获后，我们观察到一个非常大的C输入到土壤中的高Fr死亡率。杂草的输入量随着树木的生长而减少。土壤呼吸平均值为568.9 g C m−2 yr−1。三年来，DOC的沥滤量从7.9 g C m− 2增加到14.5 g C m−2。基于库的方法表明，SOC库在4年期间增加了3360 g C m−2，与基于通量的方法估计的−27 g C m−2和涡度协方差+生物统计方法估计的−956 g C m − 2相比，这是很高的。高不确定性与基于汇总的方法相关。我们的研究结果表明，在我们的研究中心，使用C通量方法评估短期/中期SOC平衡，而SOC池变化仅可用于长期C平衡评估。
Uncertainty in soil carbon (C) fluxes across different land‐use transitions is an issue that needs to be addressed for the further deployment of perennial bioenergy crops. A large‐scale short‐rotation coppice (SRC) site with poplar (Populus) and willow (Salix) was established to examine the land‐use transitions of arable and pasture to bioenergy. Soil C pools, output fluxes of soil CO 2, CH 4, dissolved organic carbon (DOC) and volatile organic compounds, as well as input fluxes from litter fall and from roots, were measured over a 4‐year period, along with environmental parameters. Three approaches were used to estimate changes in the soil C. The largest C pool in the soil was the soil organic carbon (SOC) pool and increased after four years of SRC from 10.9 to 13.9 kg C m−2. The belowground woody biomass (coarse roots) represented the second largest C pool, followed by the fine roots (Fr). The annual leaf fall represented the largest C input to the soil, followed by weeds and Fr. After the first harvest, we observed a very large C input into the soil from high Fr mortality. The weed inputs decreased as trees grew older and bigger. Soil respiration averaged 568.9 g C m−2 yr−1. Leaching of DOC increased over the three years from 7.9 to 14.5 g C m−2. The pool‐based approach indicated an increase of 3360 g C m−2 in the SOC pool over the 4‐year period, which was high when compared with the −27 g C m−2 estimated by the flux‐based approach and the −956 g C m−2 of the combined eddy‐covariance + biometric approach. High uncertainties were associated to the pool‐based approach. Our results suggest using the C flux approach for the assessment of the short‐/medium‐term SOC balance at our site, while SOC pool changes can only be used for long‐term C balance assessments.