Climate change scenario modelling of soil carbon turnover on basis of improved soil carbon pool distribution on a regional scale

区域土壤有机碳(SOC)通量和池的高分辨率表示有助于改进对气候变化和反馈对农业生态系统的影响的评估。然而，动态土壤有机碳库模型(即DAISY)中的土壤有机碳库划分仍然具有挑战性，特别是在考虑气候条件变化的驱动影响时，例如单个土壤有机碳库的温度敏感性。当在存在生态系统和农场系统异质性的区域尺度上进行SOC建模时，这种约束的复杂性被放大。我们建议在第二阶段对DAISY SOC周转模型进行改进，包括为两个SOC池SOM1和SOM2开发新的通用SOC稳定性指数，以及基于SMB1和SMB2池的微生物酶活性生成微生物池划分指数，并考虑底物利用效率。这些基本步骤将主要通过进一步开发基于红外(IR)的技术(漫反射中红外傅里叶变换光谱(MID-DRIFTS)、演化气体分析(EGA)、中红外光谱分析、热解-MIRS)来实现，从而能够在区域尺度上对有机碳和微生物生物量池进行高通量、与土壤质地无关的分析。将采用类似的技术为两个添加的有机质库AOM1和AOM2生成作物残渣质量指数，作为C和N循环的初始调节器。为了考虑两个模式地区(Kraichgau和Swabian Alb)气候变异性的预测影响，SOC模式将通过相应的C和N池的显式温度函数来进一步发展。为了校准和验证动态SOC模型，我们将恢复到两个模型区域的实验场现场，并考虑我们现有的与国际研究人员在长期野外实验中的合作。在与1695年新的综合陆地系统模式系统(ILMS)连接之前，将使用DAISY-EXPERTN对与预期区域气候的影响有关的单个参数和组合参数进行敏感性分析，这些参数与高级区域SOC模式有关。相关的已开发和参数化的模式例程和高分辨率区域土壤输入地图将纳入ILMS。在最后一步中，将评估在有和没有改进CN模块的情况下，不同土地利用方式下的气候情景分析对土壤碳动态和来自大气的反馈的影响，以得出改进土壤碳固定方法的建议。

A high resolution representation of regional soil organic C (SOC) fluxes and pools facilitates an improved assessment of impacts of climate change and feedbacks on agro-ecosystems. However, soil organic carbon (SOC) pool partitioning in dynamic SOC models (i.e., DAISY) remains challenging, in particular when considering the driving influence of changing climatic conditions, e.g., by temperature sensitivities of individual SOC pools. The complexity of this constraint is magnified when SOC modelling is performed at a regional scale, where ecosystem and farm system heterogeneity exist. We propose an improvement of the DAISY SOC turnover model in Phase 2 including the development of novel and generic SOC stability indexes for the two SOC pools SOM1 and SOM2 as well as the generation of a microbial pool partition index based on activities of microbial enzymes for SMB1 and SMB2 pool distinction also considering substrate utilisation efficiencies. These essential steps will be primarily achieved through a further development of infrared (IR)-based techniques (diffuse reflectance mid-infrared Fourier transform spectroscopy (midDRIFTS), evolved gas analysis (EGA), in situT midDRIFTS, pyrolysis-MIRS) allowing a high-throughput, soil texture-independent analysis of SOC and microbial biomass pools at regional scale. Similar techniques will be employed to generate crop residue quality indexes for the two added organic matter pools AOM1 and AOM2 as initial regulators of C and N cycling. To account for the projected impact of climate variability in the two model regions (Kraichgau, Swabian Alb), the SOC model will be furthered through explicit temperature functions for corresponding C and N pools. For calibration and validation of the dynamic SOC model, we will revert to the experimental field sites in the two model regions as well as considering our existing cooperations with international researchers at long-term field experiments. Prior to coupling to the new Integrated Land-system Model System (ILMS) of FOR 1695, sensitivity analysis of individual and combined parameters related to the impact of expected regional climate with the advanced regional SOC model will be performed with DAISY-EXPERTN. The relevant developed and parameterised model routines and high resolution regional soil input maps will be incorporated into ILMS. In the final step, impacts of respective climate scenario analysis under alternative land uses, with and without improved CN module, on soil C dynamics and feedback from the atmosphere will be evaluated to derive recommendations for improved soil C sequestration approaches.