Im Rahmen des Forschungsvorhabens Timber Earth Slab (T.E.S.) schließen sich Branchenexperten aus der Industrie aus den Bereichen Holzbau und Lehmbau mit Professuren der TU München aus den Disziplinen Digitaler Fertigung, Holzbau und Baukonstruktion, Klimadesign und Architektur zusammen, um im mehrgeschossigen Holzbau einen grundlegenden Beitrag hin zum CO2-neutralen Bauen anzustoßen: T.E.S., eine industriell gefertigte Net-Zero Holz-Lehm-Decke. Geschossdecken sind eine zentrale Komponente für das Erreichen der CO2-Neutralität im mehrgeschossigen Holzbau mit sehr hohen Anforderungen an den Brandschutz, thermischer Masse und Schallschutz. T.E.S. kombiniert computergestütztes Design, robotisch gestützte Fertigung und Materialtechnologie, um eine neue innovative Lösung für die industrielle Fertigung eines ressourceneffizienten und funktionsintegrierten Deckensystems aus Holz und Lehm zu erforschen, das alle strukturellen und bautechnischen Anforderungen für den mehrgeschossigen Holzbau erfüllt, außerdem CO2-neutral hergestellt werden kann und vollständig rezyklierbar ist. Mithilfe der Materialtechnologie des ETH-Spinoffs Oxara, mit der Lehm mit geringem Wasseranteil fließfähig gemacht und vergossen werden kann, und robotischer Fertigungstechnologie, die die maßgeschneiderte Herstellung einer auf den Fließlehm abgestimmten feingliedrigen Holzkonstruktion ermöglicht, verspricht T.E.S. ein hybrides Deckensystem, welches die Stärken beider Materialien ideal kombinieren lässt: Durch die guten statischen Eigenschaften von Holz in Kombination mit den positiven Eigenschaften des Lehms hinsichtlich thermischer Masse, der Möglichkeiten zur thermischen Aktivierung, Brandschutz und Schallschutz können mit T.E.S. Nachhaltigkeit, Performativität und Kosteneffizienz in einer Deckenkonstruktion zusammengebracht werden.
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).
In subsoils, organic matter (SOM) concentrations and microbial densities are much lower than in topsoils and most likely highly heterogeneously distributed. We therefore hypothesize, that the spatial separation between consumers (microorganisms) and their substrates (SOM) is an important limiting factor for carbon turnover in subsoils. Further, we expect microbial activity to occur mainly in few hot spots, such as the rhizosphere or flow paths where fresh substrate inputs are rapidly mineralized. In a first step, the spatial distribution of enzyme and microbial activities in top- and subsoils will be determined in order to identify hot spots and relate this to apparent 14C age, SOM composition, microbial community composition and soil properties, as determined by the other projects within the research unit. In a further step it will be determined, if microbial activity and SOM turnover is limited by substrate availability in spatially distinct soil microsites. By relating this data to root distribution and preferential flow paths we will contribute to the understanding of stabilizing and destabilizing processes of subsoil organic matter. As it is unclear, at which spatial scale these differentiating processes are effective, the analysis of spatial variability will cover the dm to the mm scale. As spatial segregation between consumers and substrates will depend on the pore and aggregate architecture of the soil, the role of the physical integrity of these structures on SOM turnover will also be investigated in laboratory experiments.