Large-scale conversion of tropical peat swamp forests to agricultural plantations has resulted in substantial carbon dioxide (CO) emissions. Despite consensus on the importance of these emissions, the cause of the large range in the magnitudes of reported values remains uncertain. Differences in reported fluxes might result from site specific factors and/or potential limitations of the manual flux chambers commonly used. It is important that any biases at the site level are explored as they ultimately affect regional and global emission estimates. Therefore, the aim of this study is to determine if measurement timing of commonly used infrequent manual chamber measurements leads to biased emission estimates. In this study we make use of six months of automated chamber data to provide a semi-continuous timeseries. This timeseries is used to explore the potential for time-of-day sampling biases in infrequent, monthly manual chambers measurements in a peatland oil palm plantation in Malaysian Borneo. Fluxes from Palm Base, Harvest Path, Frond Pile, Drain and Inter row microforms were recorded hourly using automatic chambers. From these hourly data, mean diurnal patterns of fluxes were produced. These diurnal patterns were used to characterize the biases in a larger, monthly flux manual chamber dataset. This monthly manual dataset was collected over six years at the same site and microforms, with individual measurements made in the daytime. Bias range was widest for Harvest Path (-18 to 24 %), followed by Palm Base (-13 to 11 %), Drain (-10 to 9 %) and Frond Pile (-5 to 3 %). Estimates of annual plantation scale emission over six years, corrected for sampling bias ranged from 36 – 53 Mg CO ha yr. We recommend careful consideration of artefacts sample timing might introduce in any sampling design, and where possible fluxes should be corrected with measured diurnals for each microform considered.

中文翻译：

---

减少土壤表面二氧化碳通量排放测量的偏差：东南亚热带泥炭地上成熟油棕（Elaeis guineensis）种植园的案例研究

热带泥炭沼泽森林大规模转变为农业种植园导致大量二氧化碳（CO）排放。尽管人们对这些排放的重要性达成了共识，但报告值大小差异较大的原因仍不确定。报告的通量差异可能是由于场地特定因素和/或常用手动通量室的潜在限制造成的。重要的是，要探讨站点层面的任何偏差，因为它们最终会影响区域和全球排放估算。因此，本研究的目的是确定常用的不频繁手动室测量的测量时间是否会导致排放估算出现偏差。在这项研究中，我们利用六个月的自动化室数据来提供半连续时间序列。该时间序列用于探索马来西亚婆罗洲泥炭地油棕榈种植园每月不频繁进行的手动室测量中的每日时间采样偏差的可能性。使用自动室每小时记录来自棕榈基部、收获路径、叶堆、排水管和行间缩微模型的通量。根据这些每小时的数据，产生了通量的平均日模式。这些昼夜模式用于表征更大的每月通量手动室数据集中的偏差。该每月手动数据集是六年来在同一地点和缩微形式收集的，并在白天进行了单独测量。收获路径的偏差范围最宽（-18 至 24 %），其次是棕榈基（-13 至 11 %）、排水沟（-10 至 9 %）和叶状体堆（-5 至 3 %）。六年内种植园规模排放量的估计（修正抽样偏差）范围为每公顷 36 – 53 毫克二氧化碳。我们建议仔细考虑在任何采样设计中可能引入的人工制品采样时间，并且在可能的情况下，应使用所考虑的每个缩微制品的测量日数来校正流量。