Global pattern and change of cropland soil organic carbon during 1901-2010: Roles of climate, atmospheric chemistry, land use and management
Global pattern and change of cropland soil organic carbon during 1901-2010: Roles of climate, atmospheric chemistry, land use and management
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DOI：
10.1016/j.geosus.2020.03.001
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发表时间：
2020-03
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影响因子：
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通讯作者：
W. Ren;K. Banger;B. Tao;Jia Yang;Yawen Huang;H. Tian
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作者：
W. Ren;K. Banger;B. Tao;Jia Yang;Yawen Huang;H. Tian
农田土壤有机碳（SOC）是保证粮食安全和农业可持续发展的重要土壤质量指标，也是全球碳收支的重要组成部分。如果进行可持续管理，土壤可以通过固碳和减少温室气体排放到大气中，在减缓气候变化方面发挥关键作用。然而，由于地表高度异质性、机制复杂性和影响因素多样性，全球农田土壤有机碳的数量和时空格局还远没有得到很好的约束。在这里，我们使用一个基于过程的农业生态系统模型（DLEM-Ag）结合不同的空间明确的网格环境数据，以量化1901-2010年期间全球农田面积的SOC存储的长期趋势，并确定气候变化，CO2浓度升高，氮沉降，土地覆盖变化和土地管理措施（如氮肥使用和灌溉）的相对影响。结果表明，与20世纪初相比，2000年代的总SOC和SOC密度分别增加了125%和48.8%。这种SOC的增加主要归因于农田扩张和氮肥的使用。因子分析表明，在过去的110年里，气候变化减少了约3.2%（或2,166 Tg C）的总SOC。我们的研究结果表明，农田有很大的潜力，通过实施更好的土地利用管理措施，这可能会部分抵消气候变化造成的SOC损失固碳。
Soil organic carbon (SOC) in croplands is a key property of soil quality for ensuring food security and agricultural sustainability, and also plays a central role in the global carbon (C) budget. When managed sustainably, soils may play a critical role in mitigating climate change by sequestering C and decreasing greenhouse gas emissions into the atmosphere. However, the magnitude and spatio-temporal patterns of global cropland SOC are far from well constrained due to high land surface heterogeneity, complicated mechanisms, and multiple influencing factors. Here, we use a process-based agroecosystem model (DLEM-Ag) in combination with diverse spatially-explicit gridded environmental data to quantify the long-term trend of SOC storage in global cropland area during 1901-2010 and identify the relative impacts of climate change, elevated CO2, nitrogen deposition, land cover change, and land management practices such as nitrogen fertilizer use and irrigation. Model results show that the total SOC and SOC density in the 2000s increased by 125% and 48.8%, respectively, compared to the early 20thcentury. This SOC increase was primarily attributed to cropland expansion and nitrogen fertilizer use. Factorial analysis suggests that climate change reduced approximately 3.2% (or 2,166 Tg C) of the total SOC over the past 110 years. Our results indicate that croplands have a large potential to sequester C through implementing better land use management practices, which may partially offset SOC loss caused by climate change.