Exploration and modeling of the transport of mobile organic substances in the topsoil-subsoil-aquifer continuum

可移动有机颗粒物质(MOPS)不仅在农业土壤中是土壤碳循环中被忽视的组成部分，它还包括有机分子、植物残体、有机矿物团聚体和(微生物)生物等。一旦在表土中产生拖把，向更深的区域运输，不仅可以为地下食物网提供燃料，还可以促进它们的多样性。第一阶段的研究结果表明，MOPs的释放是由单个事件触发的，而迁移是由优先流控制的，并且生物孔具有特殊的重要性。我们的重点是对MOP释放和运移的机理理解和数值模拟，以及阐明它们在农业土壤表土-底土-含水层-连续体中的碳流作用。我们的目标是(I)描述MOPS谱的特征，包括垂直流动路径上的(微生物)；(Ii)定量评估作为外力和水力条件的函数的水和MOPS的动态；(Iii)研究生物孔、水力条件的作用及其与气候/人为因素的相互作用；以及(Iv)模拟水和MOPS的动态，从而建立一个“统一的食物网”模型。实验室和田间实验方法的核心是探索水和拖把在外力(气候、轨道、人为)下的动态，以及作为作物类型、休耕时间和耕作操作通过拖把输入的碳的函数。通过我们的研究，我们将有助于更好地定量了解拖把在地下食物网中对碳流和多样性的作用。

Mobile organic particulate substances (MOPS), which comprise among others organic (ma-cro)molecules, plant residues, organo-mineral aggregates, and (micro)organisms are the neglected component of the soil carbon cycle not only in agricultural soils. Once generated in the topsoil, MOPS transport into deeper zones may not only fuel the subsoil foodwebs but also contribute to their diversity. Results of the first phase suggest that MOPS release is trig-gered by singular events, while transport is governed by preferential flow with particular im-portance of biopores. Our main foci are the mechanistic understanding and numeric model-ling of the release and transport of MOPS and the elucidation of their role for the carbon-flow in the topsoil-subsoil-aquifer-continuum of agricultural soils. Our objectives are (i) to charac-terize the MOPS spectrum including (micro) organisms along the vertical flowpath, (ii) to quantitatively asses water and MOPS dynamics as a function of external forcings and hy-draulic conditions, (iii) to investigate the role of biopores, the hydraulic conditions and their interplay with climatic/anthropogenic factors, and (iv) to model water and MOPS dynamics, thereby contributing to a “unified foodweb” model. Central to the lab and field experimental approach is the exploration of the water and MOPS dynamics in response to external forcing (climate, orbital, anthropogenic) and as a function of the input of carbon via MOPS by crop type, fallow times, and tillage operation. With our research, we will contribute to an improved quantitative understanding of the role of MOPS for carbon flow and diversity in subsoil food-webs.