Modelling the Impact of Liquid Organic Fertilization and associated Application Techniques on N2O and N2 Emissions from Agricultural Soils

对耕地土壤施用液态肥料会影响氮素向大气的损失，包括NO、N2O和N2以及硝酸盐的淋滤。这些排放降低了作物氮素利用效率，造成了温室效应和平流层臭氧的破坏以及水生资源的污染。其程度取决于肥料施用技术与肥料和土壤性质之间复杂的相互作用。虽然已知肥料对氮转化（包括气体通量）的影响类型，但其预测仍然很差，因为以前的研究大多排除了N2通量的量化，而目前的模型没有考虑土壤中肥料组分空间分散引起的过程动力学。我们的建议解决了一般问题，即液体粪肥施肥及其应用模式如何影响农业土壤中的N2O和N2通量，如何优化它们在保持作物产量的同时减少排放，以及如何改进模型以找到答案。我们将通过有针对性的实验来解决这个问题，量化控制条件下土壤-粪肥系统的N2、N2O和NO通量以及总矿化和硝化速率，并利用结果来评估和改进模型。工作计划的第一部分包括实验室试验，比较不同的液肥施用技术结合土壤和粪肥性质对N2O和N2排放的影响。这将是测试和改进经验和基于过程的模型的基础。此外，我们将使用微渗仪实验和合作项目的现场实验数据来测试模型。第二部分的工作方案包括基于实验数据的模型测试和改进。我们将首先测试和校准一个现有的概念性“静态模型”，该模型考虑了粪便成分的空间分布。这是为了评估其概念方法在机械数值模型中实现的潜在有用性。对于后者，我们计划使用模型coumodel和DNDC。这些模型可以通过预测呼吸、扩散、矿化、pH的相互作用及其随时间对硝化和反硝化的影响，动态模拟浆液施用技术的影响。这两个模型都是设计来模拟大块土壤条件和仅与土壤-大气梯度有关的运输。我们将使用“静态模型”算法实现对有机热点产生的梯度进行建模的能力。工作计划的最后一部分将利用改进的模型评估粪便对耕地农业的影响和潜在的温室气体减排方案。模拟将被设计用于测试现实环境条件的假设，以预测在各种土壤和气候条件下粪便对N2和N2O通量的影响，并依赖于粪便的性质。

Fertilizing arable soils with liquid manures affects gaseous N losses to the atmosphere including NO, N2O and N2 as well as nitrate leaching. These emissions impair nitrogen use efficiency of crops and contribute to the greenhouse effect and stratospheric ozone destruction and pollution of aquatic resources. Their extent depends on the complex interaction between manure application techniques and properties of manures and soil. Whereas the type of manure effects on N transformations including gaseous fluxes is known, their prediction is still poor because previous investigations mostly excluded N2 flux quantification and current models do not consider the process dynamics arising from the spatial dispersion of manure components within the soil. Our proposal addresses the general question, how liquid manure fertilization and its application mode impact N2O and N2 fluxes from agricultural soils, how their optimization could mitigate emission while maintaining crop yields and how models would have to be improved to find answers. We will address this by targeted experiments to quantify N2, N2O and NO fluxes as well as gross rates of mineralization and nitrification of soil-manure systems under controlled conditions and using results to evaluate and improve models. The first part of the work program includes laboratory experiments to compare the effect of different techniques of liquid manure application in combination with soil and manure properties on N2O and N2 emissions. This will be a basis to test and improve empirical and process based models. Furthermore, we will use data from micro-lysimeter experiments and field experiments from cooperating projects to test the models. The second part of the work program includes model testing and improvement based on the experimental data. We will first test and calibrate an existing conceptual "Static Model" that takes into account spatial distribution of manure components. This is to evaluate the potential usefulness of its conceptual approach for implementation into mechanistic numerical models. For the latter we plan to use the models CoupModel and DNDC. These models could simulate the effects of slurry application techniques dynamically by their ability to predict the interaction of respiration, diffusion, mineralization, pH and their impact on nitrification and denitrification over time. Both models are designed to model bulk soil conditions and transport only in relation to soil-atmosphere gradients. We will implement the ability to model gradients due to organic hotspots using algorithms of the "Static Model".The last part of the work program will evaluate manure effects in arable agriculture and potential greenhouse gas mitigation options using improved models. Simulations will be designed for testing assumptions of realistic environmental conditions in order to predict manure effects on N2 and N2O fluxes in various soil and climate conditions and in dependence of manure properties.