The adoption of no‐till (NT) has been proposed to recover soil organic carbon (SOC), which will aid the mitigation of climate change. However, studies have questioned the potential of NT soils to deliver SOC sequestration and sustain crop yields. No‐till experiments are relatively recent (<50 years) and very few studies were able to assess SOC dynamics in high‐yield agroecosystems. We used the DSSAT‐CENTURY model to predict long‐term SOC (0–30 cm) using datasets from two experiments assessing tillage and nitrogen (N) sources in a Mollisol from the midwest United States (28 years) and tillage and crop rotations in an Oxisol from southern Brazil (33 years). The conversion of prairie and grassland soils to conventional agriculture decreased SOC by 61 and 12% in the Mollisol and Oxisol, respectively. Soil organic C accrual in NT soils was >0.5 Mg C ha⁻¹ year⁻¹ under medium‐low‐yield maize in the Mollisol and negligible in the Oxisol under soybean/wheat rotation. Organic fertilization and crop rotation increased SOC accrual at both sites. Simulated SOC had good agreement with observations for NT soils but overestimated SOC in tilled soils. The model's parameters were then modified for tilled soils. Long‐term simulations (100 years) revealed that SOC accrual in NT soils (0–15 cm) is partially offset by losses at 15–30 cm under low C inputs. Simulations with best crop management practices (BP; irrigation, high‐yield cultivars, higher plant density and improved N fertilization) augmented C inputs and SOC stocks, ultimately recovering SOC to the levels of prairie soils. Our results suggest that the adoption of NT, recycling of organic fertilizers and the use of BP should be further promoted for recovery and permanence of SOC in agricultural soils.

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使用DSSAT-CENTURY模型评估增强土壤固碳的策略

有人建议采用免耕（NT）来恢复土壤有机碳（SOC），这将有助于缓解气候变化。但是，研究人员质疑NT土壤能否实现SOC隔离和维持农作物产量。免耕试验是相对较新的（<50年），很少有研究能够评估高产农业生态系统中的SOC动态。我们使用DSSAT-CENTURY模型，使用来自两个实验的数据集来预测长期SOC（0–30 cm），这些数据评估了来自美国中西部（28年）的Mollisol中的耕作和氮（N）源以及美国耕作和作物轮作来自巴西南部的Oxisol（33年）。草原和草地土壤向常规农业的转化分别使Mollisol和Oxisol的SOC降低61％和12％。NT土壤中有机碳的积累> 0。^-1年^-1在大豆/小麦轮作下，玉米在Mollisol中处于低产玉米之下，而在Oxisol中则微不足道。在两个地点，有机肥和轮作增加了SOC的累积。模拟的SOC与NT土壤的观测值吻合良好，但耕作土壤的SOC被高估了。然后针对耕种土壤修改模型的参数。长期模拟（100年）显示，在低碳输入下，NT土壤（0-15 cm）中的SOC累积被15-30 cm处的损失部分抵消。利用最佳作物管理实践（BP；灌溉，高产品种，更高的植物密度和改善的氮肥施肥）进行的模拟增加了碳投入和有机碳储量，最终使有机碳恢复至草原土壤的水平。我们的结果表明采用NT