Management-induced changes in soil organic carbon on global croplands
Management-induced changes in soil organic carbon on global croplands
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DOI：
10.5194/bg-19-5125-2022
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发表时间：
2022-11
期刊：
影响因子：
4.9
通讯作者：
K. Karstens;B. Bodirsky;J. Dietrich;M. Dondini;J. Heinke;M. Kuhnert;Christoph Müller;S. Rolinski;Peter Smith;I. Weindl;H. Lotze-Campen;A. Popp
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作者：
K. Karstens;B. Bodirsky;J. Dietrich;M. Dondini;J. Heinke;M. Kuhnert;Christoph Müller;S. Rolinski;Peter Smith;I. Weindl;H. Lotze-Campen;A. Popp
抽象的。土壤有机碳（SOC）是地球上最大的陆地碳（C）储量之一，由于人为土地覆被变化和农业管理的影响，土壤有机碳已逐渐耗竭。然而，到目前为止，后者在全球碳存量评估中没有得到充分体现。虽然SOC模型经常模拟导致SOC积累和衰减的详细生物化学过程，但在全球范围内，驱动这些生物物理过程的管理决策仍然很少被研究。在这里，我们开发了一个空间上明确的数据集农田农业管理，考虑作物生产水平，残留物归还率，粪肥的应用，并通过灌溉和耕作的做法。我们将其与基于政府间气候变化专门委员会（IPCC）第2层方法的降低复杂性模型相结合，以创建前30 cm矿质土壤SOC储量和SOC储量变化的半度分辨率数据集。我们估计，由于耕地，土壤已经失去了约34.6 GtC相对于1975年的反事实假设的自然状态。在1975年至2010年期间，SOC债务继续扩大5 GtC（0.14 GtC yr-1），达到约39.6 GtC。然而，考虑历史管理导致排放量比持续管理假设下减少2.1 GtC（0.06 GtC yr-1）。我们还发现，管理决策的影响历史SOC轨迹最强烈的残留物返回，表明SOC增强生物质保留可能是一个很有前途的负排放技术。降低复杂性的SOC模型可以让我们模拟管理引起的SOC增强-也在计算要求高的综合（土地利用）评估建模。
Abstract. Soil organic carbon (SOC), one of the largest terrestrial carbon (C) stocks on Earth, has been depleted by anthropogenic land cover change and agricultural management. However, the latter has so far not been well represented in global C stock assessments. While SOC models often simulate detailed biochemical processes that lead to the accumulation and decay of SOC, the management decisions driving these biophysical processes are still little investigated at the global scale. Here we develop a spatially explicit data set for agricultural management on cropland, considering crop production levels, residue returning rates, manure application, and the adoption of irrigation and tillage practices. We combine it with a reduced-complexity model based on the Intergovernmental Panel on Climate Change (IPCC) tier 2 method to create a half-degree resolution data set of SOC stocks and SOC stock changes for the first 30 cm of mineral soils. We estimate that, due to arable farming, soils have lost around 34.6 GtC relative to a counterfactual hypothetical natural state in 1975. Within the period 1975–2010, this SOC debt continued to expand by 5 GtC (0.14 GtC yr−1) to around 39.6 GtC. However, accounting for historical management led to 2.1 GtC fewer (0.06 GtC yr−1) emissions than under the assumption of constant management. We also find that management decisions have influenced the historical SOC trajectory most strongly by residue returning, indicating that SOC enhancement by biomass retention may be a promising negative emissions technique. The reduced-complexity SOC model may allow us to simulate management-induced SOC enhancement – also within computationally demanding integrated (land use) assessment modeling.