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

移动的有机颗粒物（MOPS）是土壤碳循环中被忽视的组成部分，它包括有机大分子、植物残体、有机无机团聚体和微生物等。MOPS一旦在表层土壤中产生，就可以向深层迁移，不仅为底土食物网提供燃料，而且还有助于其多样性。第一阶段的结果表明MOPS的释放是由单一事件触发的，而运输是由优先流控制的，特别是生物孔隙的重要性。我们的主要焦点是MOPS的释放和运输的机制的理解和数值模拟，并阐明其在农业土壤的表土-底土-含水层连续体中的碳流的作用。我们的目标是：（i）表征MOPS谱，包括沿着垂直流道的（微）生物;（ii）定量评估水和MOPS动态作为外部强迫和水力条件的函数;（iii）研究生物孔隙的作用、水力条件及其与气候/人为因素的相互作用;（iv）模拟水和MOPS动态。从而有助于形成“统一的食物网”模式。实验室和田间实验方法的核心是探索响应外部强迫（气候，轨道，人为）的水和MOPS动态，并通过作物类型，休耕时间和耕作操作的MOPS作为碳输入的函数。通过我们的研究，我们将有助于更好地定量了解MOPS对底土食物网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.