Sequestration of organic C in agricultural soils is necessary to improve soil health to meet the challenges of climate change, diminishing biodiversity, water quality deterioration, and rising demands for food and fiber production. New assessment approaches are needed to quantify how conservation agriculture might contribute to soil health improvement and soil organic C (SOC) sequestration. In the southeastern United States, conservation management has been repeatedly shown to stratify SOC concentration with depth. Starting immediately below a zone of tillage influence (i.e., 30‐cm depth), SOC concentration is rarely affected by management due to low C inputs and high decomposition potential, whereas concentration increases toward the surface in a nonlinear manner, presumably with greater inputs of residue and root inputs and changing temperature and moisture conditions. Using these observations as an ecological foundation, SOC sequestration was calculated as the summation of SOC stock greater than the baseline condition at 30‐cm depth. Data from literature sources were mathematically fitted with this new approach as a validation. Two on‐farm surveys with different agricultural management practices (5–40 yr) in the southeastern United States yielded preliminary estimates of SOC sequestration. The interquartile range of calculated SOC sequestration was 4.2–9.4 Mg C ha^–1 for conventional‐tillage cropland (n = 45 fields), 13.6–29.7 Mg C ha^–1 for no‐tillage cropland (n = 97 fields), and 15.9–26.1 Mg C ha^–1 for perennial pasture (n = 29 fields). This new approach will be valuable to estimate SOC sequestration from a greater diversity of conservation agricultural systems practiced on farms within a region and independent of soil type.

中文翻译：

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根据深度分布计算土壤有机碳固存

螯合农业土壤中的有机碳对于改善土壤健康，应对气候变化，减少生物多样性，水质恶化以及对食品和纤维生产的需求增加的挑战是必不可少的。需要新的评估方法来量化保护性农业如何有助于土壤健康改善和土壤有机碳（SOC）隔离。在美国东南部，保护管理已多次被证明可以对SOC浓度进行深度分层。从紧邻耕作影响的区域（即30 cm深度）开始，由于低C输入和高分解电位，SOC浓度几乎不受管理的影响，而浓度则以非线性的方式向地表增加，大概有更多的残留物和根部投入物，以及温度和湿度条件的变化。使用这些观察结果作为生态基础，可以计算出SOC隔离量，即SOC储量的总和大于30 cm深度处的基线条件。来自文献来源的数据在数学上符合此新方法的要求，以进行验证。在美国东南部的两次农场调查中，采用了不同的农业管理实践（5-40年），初步估算了SOC的固存量。计算得出的SOC隔离量的四分位数范围为4.2–9.4 Mg C ha 来自文献来源的数据在数学上符合此新方法的要求，以进行验证。在美国东南部的两次农场调查中，采用了不同的农业管理实践（5-40年），初步估算了SOC的固存量。计算得出的SOC隔离量的四分位数范围为4.2–9.4 Mg C ha 来自文献来源的数据在数学上符合此新方法的要求，以进行验证。在美国东南部的两次农场调查中，采用了不同的农业管理实践（5-40年），初步估算了SOC的固存量。计算得出的SOC隔离量的四分位数范围为4.2–9.4 Mg C ha^–1为常规耕地（n  = 45田），13.6–29.7 Mg C ha ^–1为非耕地（n  = 97田）和15.9–26.1 Mg C ha ^–1为多年生牧场（n  = 29字段）。这种新方法对于根据区域内不同土壤类型的农场所实施的更大范围的保护性农业系统来估算SOC封存量将是有价值的。