Project Details
Projekt
Ecosystem nutrition as driver of soil organic matter turnover, a modelling approach
Applicants
Dr. Marion Schrumpf; Dr. Sönke Zaehle
Subject Area
Soil Sciences
Term
from 2016 to 2021
Project identifier
Deutsche Forschungsgemeinschaft (DFG) - Project number 320333754
Long-term ecosystem monitoring suggests that increasing atmospheric CO2 and continued nitrogen (N) deposition may drive forest ecosystems into phosphorus (P) limitation, with significant impacts on forest functioning. However, the processes controlling the biological availability of P, and their dependence on soil development and weathering are not sufficiently understood. In its first phase, the SPP 1685 has collected a unique data set on P cycling in acquiring (i.e. predominantly weathering-driven P availability) and recycling (i.e. predominantly organic-matter-driven P availability) ecosystems. We propose to develop a novel process-based, biogeochemical soil model of the C, N, and P cycles to integrate these observations with a mathematical representation of the major biogeochemical processes, and thereby to put the observations into one consistent framework. We hypothesise that soil organic matter turnover is pivotal to maintain ecosystem nutrition along the gradient of P availability. To better understand the soil C dynamics at different levels of P availability, we will add some critical analyses on the C turnover in these forest soils using the 14C technique. The model will be built on an existing model of soil organic C turnover, transport, and stabilisation in the soil column, and represent the organic and inorganic N and P cycle as well as differential nutrient acquisition strategies of plants and microbes. With this model, we will study the effects of different levels of P supply, in particular the role of soil organic matter storage and turnover on biological P availability. While trying to keep the model simple, the processes implemented should be able to correctly predict ecosystem responses to the experimental fertilization planned in the second phase of the SPP 1685. The model development will contribute to a better understanding of the underlying causes for the shift between P acquiring and recycling ecosystems, and offer the potential to apply this knowledge regionally and for the study of CO2 fertilization and N deposition on forest ecosystems.
DFG Programme
Priority Programmes
