The effects of climate change are already being felt in Germany, with high temperatures and water shortages causing fats and waxes to accumulate on the ground, preventing water absorption and leading to severe erosion. The low rainfall since the extreme drought of 2018 has resulted in dried-out plants, high risk of forest fires, and drying out of moors. Even wheat harvests in moderate climate regions like Germany are threatened by water scarcity and global warming. Despite heavy rainfall this summer, the Helmholtz Centre for Environmental Research’s Drought Monitor shows that soil moisture levels have not returned to their previous levels, with many regions still experiencing moderate to extreme drought in the top 25 centimeters of soil.
A study by the Federal Institute for Geosciences and Natural Resources (BGR) has shown that the recovery of soils from their previous strong drying out is hindered by the fact that the soil surface becomes water-repellent, a paradoxical effect known as wetting inhibition. This is caused by fats and waxes from plants being released and deposited on mineral soils during dry periods, making it difficult for the soil to absorb rainwater, leading to water runoff and continued dryness. Wetting inhibition also leads to stronger soil erosion, washing away fertile soil and further worsening the living conditions of many plants. To investigate the extent of wetting inhibition in Germany, BGR researchers analyzed soil samples, climate data, and satellite images, allowing them to make statements about the wetting ability of soils on a landscape scale.
The study’s results can be used to develop countermeasures for affected areas, including targeted irrigation and the addition of wetting-promoting substances such as clay. The project also aims to help better understand the consequences of climate change, with heatwaves becoming a more frequent phenomenon in Germany in the future, exacerbating the problem of water-repellent soils.
