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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. 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. 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. 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. 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. • IPCC tier 3 approach was applied to quantify cropland SOC sequestration potential. • 20% increase in C input would not be enough to meet the 4‰ target over 2021–2040. • Climate change would reduce SOC sequestration on average by 0.28 t C ha−1 yr−1. • 20% additional C input is not enough to compensate climate change impact on SOC. • Contribution of C input, temperature, precipitation to SOC sequestration is 56%, 24%, and 20%. [ABSTRACT FROM AUTHOR]

Peatlands provide habitats for many species and a variety of ecosystem services worldwide. In this study we used an integrated biophysical-economic modeling approach with multi-objective optimization to investigate how alternative land-use and land-management (LULM) options jointly affect economic returns from marketed (timber, energy peat, restoration costs) and non-marketed public goods (water quality, GHG emissions, biodiversity) in a typical landscape dominated by peatlands in northern Finland. We considered several LULM options including no action (the current state will continue), bioenergy wood harvesting, intensive forest management, restoration, and energy peat extraction with three after use options (no after use, reforestation, rewetting). Our study revealed strong tradeoffs between biodiversity and ecosystem services in drained peatlands. Optimal LULM depended strongly on the chosen objectives, i.e. whether marketed or non-marketed goods were preferred. For example, when the objective was carbon neutral land-use, the no action option was mostly chosen, while bioenergy wood harvesting was mostly chosen when the objective was to provide economic and environmental benefits at the same time. The strong tradeoff between biodiversity and ecosystem services indicates that compromises are unavoidable in order to obtain a multi-functional landscape which provides biodiversity conservation, climate change mitigation and water protection in a cost-effective manner. • Selection of alternative land-management options for peatlands was analyzed. • The cost-impact analysis utilized multi-objective optimization. • The variables were the NPV, biodiversity, climate impact, and water emissions. • A small decrease in the NPV resulted in a clear increase in environmental benefits. • Optimal land-management depended strongly on the chosen objectives. [ABSTRACT FROM AUTHOR]