PRS Publications

Have this publication emailed to you.

The influence of drought and rewetting on plant and soil nutrient dynamics

Lenaerts, B . 2020. University of Antwerp


Global climate change is currently already impacting the world as we know it and will do so even more in the future. An increase in the frequency of extreme weather events and intensification of the global hydrological cycle are among the expected consequences. Changes in precipitation patterns and altered evapotranspiration will lead to prolonged droughts in many regions. In soils, when droughts come to an end, rewetting will typically cause a temporary pulse of numerous microbial processes, known as the Birch effect. A prominent result is an elevated CO2 flux, which has been studied extensively. Effects of these mineralization and soil processes on nutrients other than carbon (to a lesser extent N and P) have been left aside. However, these other nutrients may play an important role for plants that have been subjected to drought and their recovery after rewetting. We examined the effect of rewetting on several relevant nutrients (N, P, K, Mg and Ca) in a mesocosm environment with controlled irrigation and no natural precipitation. Eight different irrigation regimes were imposed, varying between 1 and 60 days. Soil nutrient supply rates were measured with PRS probes. Plant aboveground biomass was sampled right before the major rewetting event at day 60, a week after and one month after this event. Nutrient supply rates in the soil and nutrient concentrations in the plant aboveground biomass were compared. We found a positive trend with drought length in both the nutrient supply rates and the plant biomass, indicating that post-drought recovery of plants might be mediated by nutrient release upon rewetting. However, we did not find a significant difference between nutrient supply rates, or pre and post rewetting in the plant aboveground biomass nutrients. We confirmed the Birch effect, but more research remains necessary to disclose its exact impacts and underlying mechanisms.