MINCA "MItigation of Nitrogen pollution at CAtchment scale"

集约化农业，特别是化肥的使用，是确保日益增长的世界人口的粮食供应的关键。肥料中含有的氮不仅被植物吸收并最终收获，而且还通过各种气体和水文途径以活性氮(Nr)的形式释放到环境中。这会导致严重的环境问题，如富营养化、温室气体排放或地下水污染。我们假设，基于科学的氮素缓解策略可以减少N2O和NH3的排放，并在保持产量的同时减少向水中输入的N3。因此，MINCA项目的目的是建立一个耦合的、基于过程的水文-生物地球化学模型，作为一种工具来确定田间管理策略，从而减少农业为主的景观中的氮过剩，从而减少氮污染。我们特别感兴趣的是农田、地下水、河岸和溪流界面的氮转化机制。为了克服目前在景观尺度上理解Nr转化的时空水文生物地球化学通量的局限性，我们将创新的野外实验与基于过程的建模方法相结合。然而，N循环在水-生物地球化学模型中的表示是复杂的，基本过程的验证是数据密集型的。因此，这些测量是在四个不同的农业、一个草原和一个林区进行的。MINCA由四个紧密相连的工作包(WP)组成。WP1描述了Vollnkirchener Bach研究区正在进行的水和氮流测量。已经相对广泛的连续测量，例如N2O排放量、土壤水分、径流和水质，将通过进一步的测量得到扩展，例如N3淋溶和浓度、叶面积指数的季节性发展、产量、生物量及其C和N含量。此外，还将在实地活动中测量15N2O和15NO3同位异构体。WP1中模型实验的多标准测量和WP2中基于模型的升级方法将允许WP3中的参数减少、不确定性分析和过程合理性测试。这将能够确定N污染在景观中发生的时间和地点。这一深入的知识将构成WP4中以科学为基础的缓解情景的基础。耦合模式以实时数据同化模式执行，以实现德国联邦粮食和农业部设定的目标值。量身定做的N2O排放和N3淋溶现场实验将证明缓解潜力的有效性。

The intensification of agriculture, and in particular the use of fertilizers, is the key to securing food supplies for a growing world population. The nitrogen contained in the fertilizer is not only absorbed into the plant biomass and finally harvested, but is also released into the environment as reactive nitrogen (Nr) via various gaseous and hydrological pathways. This leads to serious environmental problems such as eutrophication, greenhouse gas emissions or groundwater pollution.We assume that science-based nitrogen mitigation strategies make it possible to reduce N2O and NH3 emissions and reduce NO3 inputs into waters while maintaining yields. The aim of the MINCA project is therefore to establish a coupled, process-based hydro-biogeochemical model as an instrument for identifying field management strategies that make it possible to reduce the Nr-surplus and thus reduce N pollution in agriculturally dominated landscapes.We are particularly interested in the Nr conversion mechanisms at the interfaces of fields, groundwater, riverbanks and streams. In order to overcome the current limitations of understanding the temporal and spatial hydro-biogeochemical fluxes in Nr-transformation on the landscape scale, we will combine innovative field experiments with a process-based modelling approach. However, the representation of the N cycle in hydro-biogeochemical models is complex and the validation of the underlying processes is data-intensive. The measurements are therefore carried out on four different agricultural, one grassland and one forest area. MINCA consists of four closely linked work packages (WP). WP1 describes the ongoing measurement of water and nitrogen flows in the Vollnkirchener Bach study area. The already relatively extensive continuous measurements, e.g. N2O emissions, soil moisture, runoff and water quality, will be extended by further measurements such as NO3 leaching and concentrations, seasonal development of the leaf area index, yields, biomass and their C and N content. In addition, 15N2O and 15NO3 isotopomers will be measured in field campaigns. Multi-criteria measurements for model experiments in WP1 and model-based upscaling methods within WP2 will allow parameter reduction, uncertainty analysis and process plausibility testing in WP3. This will enable to identify when and where N pollution occurs in the landscape.This in-depth knowledge will form the basis for the development of science-based mitigation scenarios in WP4. The coupled model is executed in a real-time data assimilation mode in order to achieve the target values set by the German Federal Ministry of Food and Agriculture. Tailor-made in-situ experiments on N2O emissions and NO3 leaching will demonstrate the effectiveness of the mitigation potential.