CONTEXT

Cropland soil organic carbon (SOC) stock can be increased by agricultural management, but is subject to various factors. The extent and rates of SOC sequestration potential, as well as the controlling factors, under different climate and management practices across a region or country are important for policy-makers and land managers, however have been rarely known.

OBJECTIVE

We aim to investigate the extent and rates of SOC sequestration potential over 2021–2040 under different scenarios of climate change and Sustainable Soil Management (SSM) practices, and quantify the impacts of climate change and SSM practices on the SOC sequestration potential, for croplands across Finland at a spatial resolution of 1 km.

METHODS

RothC model is run iteratively to equilibrium to calculate the size of the SOC pools and the annual plant carbon inputs. Then, it is applied to investigate the SOC sequestration potential over 2021–2040 under different scenarios of climate change and SSM practices. Finally, facorial simulation experiments are conducted to quantify the impacts of climate change and SSM practices, alone and in combination, on SOC sequestration potential.

RESULTS AND CONCLUSION

Under the combined impacts of climate change and SSM practices, the SOC sequestration potential during 2021–2040 relative to 2020 will be on average − 0.03, 0.007, 0.05, and 0.13 t C ha⁻¹ yr⁻¹, respectively, with carbon input being business as usual, 5%, 10%, and 20% increase. This is equivalent to an annual change rate of −0.04%, 0.009%, 0.07%, and 0.17%, respectively. Therefore, a 20% increase in C input to soil will not be enough to obtain a 4‰ increase per year over the 20-year period in Finland. Carbon input will promote SOC sequestration potential; however, climate change will reduce it on average by 0.28 t C ha⁻¹ yr⁻¹. Across the cropland in Finland, on average, the relative contributions of C input, temperature, and precipitation to SOC sequestration potential in 2021–2040 will be 56%, 24%, and 20%, respectively, however there is a spatially explicit pattern. The SOC sequestration potential will be relatively high and dominated by C input in west and southwest Finland. By contrast, it will be relatively low and dominated by climate in north and east Finland, and the central part of southern Finland.

SIGNIFICANCE

Our findings provide the information as to where, how much, and which SSM practices could be applied for enhancing SOC sequestration at a high spatial resolution, which is essential for stakeholders to increase cropland SOC sequestration efficiently.

中文翻译：

---

在气候变化和农业管理的交互影响下，2021-2040 年芬兰农田的土壤有机碳封存潜力

语境

农业管理可以增加农田土壤有机碳 (SOC) 储量，但受多种因素影响。在一个地区或国家的不同气候和管理实践下，SOC 封存潜力的范围和速率以及控制因素对决策者和土地管理者很重要，但鲜为人知。

客观的

我们的目标是调查 2021-2040 年不同气候变化情景和可持续土壤管理 (SSM) 实践下 SOC 封存潜力的程度和速率，并量化气候变化和 SSM 实践对农田 SOC 封存潜力的影响芬兰，空间分辨率为 1 公里。

方法

RothC 模型迭代运行至平衡，以计算 SOC 池的大小和每年的植物碳输入。然后，将其应用于研究 2021-2040 年不同气候变化情景和 SSM 实践下的 SOC 封存潜力。最后，进行了表面模拟实验，以量化气候变化和 SSM 实践单独和组合对 SOC 封存潜力的影响。

结果与结论

在气候变化和 SSM 实践的综合影响下，2021-2040 年相对于 2020 年的 SOC 封存潜力将平均分别为 - 0.03、0.007、0.05 和 0.13 t C ha -1 yr -1 ^， 碳^输入为照常营业，增加 5%、10% 和 20%。这相当于年变化率分别为 −0.04%、0.009%、0.07% 和 0.17%。因此，在芬兰的 20 年期间，土壤碳输入增加 20% 不足以实现每年 4‰ 的增长。碳输入将促进SOC封存潜力；然而，气候变化将平均减少 0.28 t C ha ⁻¹  yr ⁻¹. 在芬兰的整个农田中，2021-2040 年碳输入、温度和降水对 SOC 封存潜力的相对贡献平均分别为 56%、24% 和 20%，但存在空间明确模式。SOC 封存潜力相对较高，主要由芬兰西部和西南部的 C 输入主导。相比之下，它将相对较低，主要受芬兰北部和东部以及芬兰南部中部的气候影响。

意义

我们的研究结果提供了关于在何处、多少以及哪些 SSM 实践可以应用于以高空间分辨率增强 SOC 封存的信息，这对于利益相关者有效增加农田 SOC 封存至关重要。