1,2,4,5,- 1Department of Soil and Environment, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden
- 2State Key Laboratory of Maize Bio–breeding, College of Agronomy and Biotechnology, China Agricultural University, Beijing, China
- 3Physics of Soils and Terrestrial Ecosystems, Institute of Terrestrial Ecosystems, ETH Zurich, Zurich, Switzerland
- 4Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
- 5PSI Center for Neutron and Muon Sciences, 5232 Villigen PSI, Switzerland
In a large field trial on sandy loam, Lama et al. (2022)1- albeit involuntary - tested the effect of drought on the performance of 300 genotypes during two contrasting years: 2017 (cool and wet) and 2018 (hot and dry). Remarkably, some genotypes achieved yields under drought conditions (2018) comparable to established high-yielding varieties. The reason for this remains unclear.
One possible explanation is that this positive effect is linked to modifications of rhizosphere wettability. Sandy soils are known to be susceptible to water repellency upon drying, and several crops, such as maize, barley, and wheat, can modify soil wettability through root exudation2. However, it is still uncertain whether rhizosphere water repellency in sandy soils is an advantage, as it can delay rewetting and thereby reduce biological activity and potentially limit root water uptake.
In this study, we investigated the effect of rhizosphere-induced wettability modifications on water dynamics in naturally water-repellent sandy soil. Using time-series neutron radiography, we quantified rewetting dynamics following a dry-down experiment. While the bulk soil exhibited reduced rewetting, preferential rewetting was observed in the rhizosphere of maize. This finding may help to explain why certain plants benefit from reduced precipitation in sandy soils. Firstly, rewetting occurs preferentially in the rhizosphere, where it can directly support microbial activity and root water uptake. Secondly, localized rewetting may reduce nutrient leaching and promote nutrient retention and turnover through localized enzyme activity.
References
1. Lama, S., Vallenback, P., Hall, S. A., Kuzmenkova, M. & Kuktaite, R. Prolonged heat and drought versus cool climate on the Swedish spring wheat breeding lines: Impact on the gluten protein quality and grain microstructure. Food Energy Secur. 11, e376 (2022).
2. Naveed, M. et al. Surface tension, rheology and hydrophobicity of rhizodeposits and seed mucilage influence soil water retention and hysteresis. Plant Soil 437, 65–81 (2019).
How to cite: Benard, P., Jia, R., Di Bert, S., Wassermann, B., Bickel, S., Kaestner, A., Zang, H., and Carminati, A.: Preferential rhizosphere rewetting in water repellent sandy soil, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-17300, https://doi.org/10.5194/egusphere-egu26-17300, 2026.
