The dynamic character of forest soil organic carbon (SOC) stocks is demonstrated in the simulation model TransparC2U. The model has up to 10 layers, each with two pools with first order kinetics running for 40 years. The model is aimed at teaching soil science to a broad audience in academia, extension services, secondary schools and public life. The learning objective of the model is to bring about an understanding of SOC dynamics over time, uncertainty, and the complexity of the soil profile with its pedogenesis represented by soil horizons. The user works in an illustrated spreadsheet calculator with options for instant and interactive exploration of the multiple uncertainties and constraints on forest SOC stocks. The user divides the initial SOC stock in each horizon into two pools, C_new with faster mineralization, and C_old with very slow mineralization, based on their knowledge of horizon designations and stabilization mechanisms.

Data from 23 soil Nordic and Baltic forest soil profiles with horizons characterized by chemical and physical properties are available. Site information to the user intended for reflections on choosing parameter values includes soil classification, tree species, climate, stand age, soil nutrient status and properties that govern physical or chemical protection of soil C (extractable phosphorus (P), total nitrogen (N), subsoil clay content and extractable iron (Fe)). Other changeable inputs are the average annual aboveground litter fall, root litter allocation to individual soil horizons as a fraction (%) of aboveground input, and decomposition rates of each pool. The game played aims for preservation of the initial C stock by manual calibration by the user. The sensitivity of the potential C change (dC ±) is tested by changing the parameter values and watching the effects on model results, i.e. C stocks in each horizon over time. The sensitivity analysis can involve the uncertainty of the input, the initial C content in each horizon, the fraction of C_old and the turnover rates that represent heterotrophic respiration.

The processes representing C input to deeper horizons (roots and exudates), bioturbation by macrofauna, as well as podzolisation provide optional transfer of C between the forest floor and mineral soil layers when judged appropriate by the user based on the site and stand information.

The user may interpret results of the simulation by examining the outputs of total C stock change over 40 years by inspecting total N and P requirements for new litter inputs against potentially available current and future N and P stocks in the soil and the capacity of C binding by subsoil clay and Fe-oxides. It highlights the physical and chemical soil properties required to justify the simulated fate of new and old SOC and the sensitivity of controlling parameters on a decadal timescale to the user.

仿真模型TransparC2U演示了森林土壤有机碳（SOC）种群的动态特征。该模型最多包含10个层，每个层有两个池，一级动力学运行40年。该模型旨在向学术界，推广服务，中学和公共生活中的广大受众讲授土壤科学。该模型的学习目标是对SOC随时间变化的动态性，不确定性以及土壤剖面及其土壤成因的成岩作用的复杂性进行理解。用户在图示的电子表格计算器中工作，该计算器具有用于即时和交互式探索森林SOC存量的多种不确定性和约束条件的选项。用户将每个层级中的初始SOC存量分为两个池，C _new更快的矿化，而C_老很慢矿化的基础上，他们的视野名称和稳定机制的认识。

提供了来自23个北欧和波罗的海森林土壤剖面的数据，这些剖面具有以化学和物理性质为特征的地貌。给用户的反映选择参数值的站点信息包括土壤分类，树木种类，气候，林分年龄，土壤养分状况以及控制土壤C（可提取磷（P），总氮（N））的物理或化学保护的特性，底土粘土含量和可提取铁（Fe））。其他可变化的输入是地上凋落物的年平均下降量，根系凋落物在各个土壤层中的分配（占地上输入的分数（％））以及每个池的分解率。玩游戏的目的是通过用户手动校准来保存初始的C库存。通过更改参数值并观察对模型结果的影响（即随时间推移每个视野中的C储量）来测试潜在C变化（dC±）的敏感性。敏感性分析可能涉及输入的不确定性，每个视野中的初始C含量，C的分数_老和周转率代表异养呼吸。

当用户根据现场和林分信息判断合适时，代表向更深层（根和渗出物）输入C的过程，大型动物对生物的扰动以及荚果化的过程提供了林地和矿质土壤层之间C的可选转移。

用户可以通过检查40年来总C储量变化的输出来解释模拟结果，方法是根据土壤中潜在可用的当前和未来N和P储量以及C结合能力来检查新垃圾输入的总N和P需求。被土壤和粘土中的铁氧化物氧化。它突出显示了证明新旧SOC的模拟结果合理所需的物理和化学土壤特性，以及对用户而言以十年为单位的控制参数的敏感性。