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Natural climate solutions (NCS) offer immediate and cost-effective ways to tackle the climate crisis by transforming atmospheric carbon to soil carbon or avoiding greenhouse gas emissions. However, the climate mitigation potential and economic costs of NCS for cropping systems in China remain inconclusive. The major objectives of this study are (i) to estimate the NGHG reduction potential across Chinese main cropping systems caused by NCS, (ii) to quantify the economic costs of adopting optimal management with different abatement potentials. The Denitrification-Decomposition (DNDC) model was used to estimate the NGHG, including SOC sequestration, N 2 O emissions, and CH 4 emissions. After calibration, we ran the DNDC model with derived data at municipality-level. We estimated the NGHG under current management, adopting optimal management individually, and integrated optimal management to project the maximum NGHG reduction potential caused by NCS. We used the marginal abatement cost method to estimate the economic cost. The four natural climate solutions, N fertilization management (NFM), straw returning management (SRM), tillage management (TM), and rice irrigation management (RIM) can reduce national NGHG in main cropping systems by approximately 118.8 Tg CO 2 -eq, 116.3 Tg CO 2 -eq, 35.2 Tg CO 2 -eq, and 74.4 Tg CO 2 -eq, respectively. The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO 2 -eq, equivalent to 90.2% of current NGHG, and 80% of which can be realized at the price of CN¥ 285 (Mg CO 2 -eq)−1. We further identify the priority NCS for different crops and regions and conclude that nitrogen fertilization management should be the priority NCS at the national level. Our findings highlight the great potential of NGHG reduction by adopting NCS precisely and the importance of optimizing agricultural management as a whole, and they will help policy makers to develop smart-agriculture in China. [Display omitted] • Estimating net greenhouse gas emissions (NGHG) reduction potentials of agriculture. • IPCC recommended tier 3 method was applied for seven cropping systems in China. • The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO 2 -eq. • 80% of NGHG mitigation can be realized at the price of CN¥ 285 (Mg CO 2 -eq)−1. • The priority NCS was identified for different crops and regions. [ABSTRACT FROM AUTHOR]

Climate change mitigation in the agricultural sector is a key policy goal. Marginal abatement cost curves allow comparing the cost-effectiveness of agricultural greenhouse gas mitigation measures. Existing studies often do not account for the heterogeneity of farms and interactions between mitigation measures. The objective of this study is to present a new approach that allows the calculation of a marginal abatement cost curve that considers farm level interaction effects of climate change mitigation measures. We assess the influence of farm structural heterogeneity on the greenhouse gas abatement potential and the corresponding abatement costs when measures are implemented jointly on the farm level. We use the bio-economic farm model FarmDyn to simulate farm-specific abatement potential and mitigation costs for a set of mixed dairy farms in a Swiss case study region (n = 66) and develop an approach to calculate a bottom-up, marginal abatement cost curve based on our sample of farms. Simulation results are used to identify and quantify the effect of heterogeneous farm structures (e.g., size, land use, etc.) on the interactions of climate change mitigation measures using regression analysis. In our study, interaction effects reduce marginal abatement costs by 7% and the overall greenhouse gas abatement potential by 3% compared to a stand-alone consideration of four climate change mitigation measures. Our analysis of how the underlying farm structures affect interaction effects between climate change mitigation measures shows that complex processes on the farm level can have ambiguous effects (i.e., increasing or decreasing greenhouse gas emissions). We conclude that our approach can provide important knowledge about how heterogeneity affects marginal abatement costs when mitigation measures interact with each other. Knowledge about the effectiveness and efficiency of climate change mitigation measures and their interaction effects improves our understanding and development of bottom-up marginal abatement cost curves, which represent an important and widely used tool to inform policymakers and stakeholders on cost-efficient and cost-effective climate change mitigation in agriculture. [Display omitted] • We calculate a marginal abatement cost curve for agricultural greenhouse gas emissions. • Our approach allows to consider interactions between mitigation measures. • The results permit to identify the heterogeneity in marginal abatement costs across farms. • A bio-economic farm level model is used for mixed dairy farms in a Swiss case study region. • Interactions are important for abatement potential and cost-effectiveness. [ABSTRACT FROM AUTHOR]