Modelling the impact of soil management on soil functions

Abstract

Soils are the central resource for the production of biomass and due to an increasing soil loss and an increasing demand for food and energy there is an enormous pressure on soils. Besides the importance of soils for biomass production there are other essential soil functions we would like to preserve. To render agricultural productions efficient and sustainable we need to develop model tools that are in the position to quantitatively predict the impact of a multitude of management measures on soil productivity and soil functions. These functions are considered as emergent properties produced by soils as complex systems. The major challenge is to handle the multitude of physical, chemical and biological processes interacting in a non-linear manner. There is a large number of validated models for specific soil processes. However, it is not possible to simulate soil functions by coupling all the relevant processes at the detailed (i.e. molecular) level where they are well understood. A new systems perspective is required to evaluate the ensemble of soil functions and their sensitivity towards external forcing. A second challenge is that soils are spatially heterogeneous systems by nature. Soil processes are highly dependent on the local soil properties and, hence, any model to predict soil functions needs to account for the specific site conditions. We propose a new model strategy based on a thorough analysis of the interactions between physical, chemical and biological processes considering their site-specific characteristics. Coupling of the observed nonlinear interaction may define the stability and the sensitivity of the systems with respect to soil productivity and soil functions. The presented approach has been developed in the framework of the BonaRes project funded by the by the German Ministry of Education and Research.