Modelling low soil water potentials for grassland ecosystems

Christina Bogner1, Eun-Young Jung2, Katharina Müller1, Bettina Engelbrecht2
1 Ecological Modelling
2 Functional and Tropical Plant Ecology

P 4.17 in BayCEERversity: Across scales, compartments & communities

Introduction

Drought and flooding have pervasive consequences on grassland composition, diversity, ecosystem function and services. With global climate change, droughts and flooding events are projected to increase. Understanding plant, community and ecosystem responses to drought and flooding is therefore important. A prerequisite to rigorously examine responses to drought is to adequately evaluate spatial and temporal variation of the variables relevant for plant performance - the soil water potential, especially at the low (dry) range. Yet, soil water potentials are rarely assessed in the relevant studies. To address this problem, in this contribution we evaluate ways to use the data sets often available in relevant studies to model low soil water potentials.

Material and Methods 

We measured the relation between soil-water potential and soil water contents with a dew point potentiometer (WP4C, Decagon Device), focusing on values below -1.5 MPa, i.e. on the range relevant for plants, for soil samples from the Biodiversity Exploratory network of grassland plots.

Results

We will combine the measurements with a modelling approach to derive soil-water retention curves for dry soil conditions, based on the approach by Schneider and Goss (WRS, Vol 48, W06603, doi:10.1029/2011WR011049, 2012).