Modelling root uptake processes in heterogeneous soils at the plant scale with a specific attention to biopores and rhizosphere impact on nutrient acquisition

土壤剖面中植物养分吸收的模式是在细胞或亚细胞水平上发生的复杂过程的结果，但影响植物环境功能中的整个植物行为，其在时间和空间上变化很大。植物养分的获取取决于根构型和生长、土壤性质和异质性以及养分和水分的三维分布。同样重要的是这些参数如何相互作用，例如养分分布和土壤特性和异质性如何影响根系生长，或养分和水分限制如何影响同化物分配。因此，需要使用空间分辨率的数学建模来解析根结构的空间结构以及养分和水分分布，以定量地解释这些复杂和相互作用的过程，并预测环境约束下的植物养分吸收行为。该项目的主要目标是建立一个建模平台，能够描述土壤中到整个根系（WP 1）的单个根系的三维流动和运输过程。模型参数将从研究组（WP 3）中以工厂规模进行的特定实验中获得，并存储在特定数据仓库（WP 2）中。将根据情景分析（WP 4）研究不同参数（描述单根尺度的根系生长和养分吸收）对土壤剖面尺度养分吸收的影响。从植物和田间规模的实验中获得的关于水分和养分吸收以及根系生长的数据将与模型预测进行比较，以验证模型。三维根尺度模型的模拟将用于验证不描述单个根尺度过程的较大尺度一维模型（WP 5和SP 10）的假设和参数化。

The pattern of plant nutrient uptake in a soil profile is the result of complex processes occurring at the cellular or sub-cellular levels but affecting the whole-plant behaviour in function of the plant environment that varies strongly in time and space. The plant nutrient acquisition depends on root architecture and growth, on soil properties and heterogeneity, and on the 3-D distribution of nutrients and water. Equally important is how these parameters interact, as for instance how the nutrient distribution and soil properties and heterogeneity impact root growth or how nutrient and water limitation affect assimilate allocation. Mathematical modelling using a spatial resolution that resolves the spatial structure of the root structure and the nutrient and water distribution is therefore needed to quantitatively account for these complex and interacting processes and to predict plant nutrient uptake behaviour under environmental constraints. The main goal of the project is to build a modelling platform able to describe 3-D flow and transport processes in the soil to individual roots of an entire root system (WP1). Model parameters will be derived from specific experiments performed at the plant scale in the research group (WP3) and stored in a specific data warehouse (WP2). The impact of different parameters, which describe root growth and nutrient uptake at the single root scale, on nutrient uptake at the soil profile scale, will be investigated based on scenario analyses (WP4). Data on water and nutrient uptake and root growth from plant and field scale experiments will be compared with model predictions to validate the model. Simulations with the 3-D root scale model will be used to validate hypotheses and parameterizations of larger scale 1-D models that do not describe processes at the scale of individual roots (WP5 and SP10).