Die Bedeutung des Wurzelumsatzes für die Nährstoffaufnahme — Eine Sensitivitätsanalyse

Abstract

Fine roots are continuously growing and dying during plant growth, i.e. the fine root system underlies a continuous turnover. By use of a mechanistic model to describe nutrient transport in the soil and nutrient uptake, it could be shown that this root turnover can be of benefit for nutrient uptake. New roots grow into undepleted soil areas and are able to perform a higher inflow than older roots in depleted soil areas. However, this result was not consistent. The model was used in a sensitivity analysis to reveal the influence of single transport and uptake parameters on calculated uptake assuming a wide range of root turnover rates. The benefit of root turnover for nutrient uptake is highest at poor nutrient availability, i.e. low soil solution concentration and low soil moisture content. Furthermore, the benefit increases with a high maximum inflow. However, these results are only a first attempt to investigate the relevance of root turnover. Exudation pattern, mycorrhiza, inhomogenuous nutrient supply, variable uptake physiology and other facts influencing nutrient uptake were not taken into account.