12/08/2022 | Water use by trees on cropland: competition or co-existence?

The integration of trees on agricultural land, also called agroforestry, is a common practice in the tropics. This practice is also becoming more relevant in temperate regions, like central Europe, as agroforestry is considered a promising approach to make agriculture more resilient to climate change. The trees can, for example, create a suitable microclimate for crops to withstand prolonged droughts or heatwaves. However, a major concern among farmers is whether the trees will compete with the crops for water.

To investigate this, the German Hydrological Society (DHG) awarded Dr. Suzanne Jacobs with a research stipend to conduct a hydrological field study at the agroforestry system that was established at the university research farm Gladbacherhof in February 2020. Using stable isotopes of water (²H and ¹⁸O) in the soil, trees and crops, Dr. Jacobs will trace back from which soil depth the trees and the crops take up their water. This will provide a first insight in whether the trees and crops are likely to compete for water from the same source and will be used as a basis for more in-depth research into the water dynamics in agroforestry systems.

 Silvoarable (i.e. trees on cropland) agroforestry system at Gladbacherhof. The tree lines consist of apple trees, high value timber trees, fast-growing poplar to produce biomass and elderberry shrubs.

Picture: S. Jacobs