FELD 1/2025

Digital Lusatia The

Digital Lusatia The small drone takes off into the blue February sky with a buzz. Squinting against the sun, Nicole Köllner steers the drone over the test field, lying barren in the winter. As part of a project in Land-Innovation-Lausitz, a scientist has sown evening primroses here on the grounds of the Leibniz Institute for Vegetable and Ornamental Crops in Großbeeren. The area is an initial test site to see how evening primrose copes with the Brandenburg climate. The drone images taken by the geologist will show where the plants have grown well. Once it has reached its starting point, the drone works on its own. At a height of 20 meters, it flies over the field according to a precisely specified pattern. It takes photos at regular intervals to create a complete image of the test area. Strictly speaking, the small aircraft does not take simple photos, but multispectral images. »There are six different cameras on the drone,« explains Köllner. »In addition to the visible red, green, and blue spectrums, they also record near-infrared radiation.« Now, in February, the tiny, roseshaped evening primroses are barely visible. With the help of an algorithm, the scientist can have them marked on the images. This makes it possible to get an overview of where the evening primroses have grown and where they have not. The drone data also shows how healthy the plants are. Lausitz Monitoring—LauMon for short—is the name of the project for which the geologist from GFZ Potsdam and her colleague Carsten Neumann are recording the land surface of Lusatia using drone data. LauMon is one of 25 projects being part of the Land-Innovation-Lausitz (LIL) alliance. 24

Digital Lusatia WHAT SATELLITES REVEAL ABOUT THE WATER CYCLES IN LUSATIA While Köllner is mapping the vegetation and soils of Lusatia in detail, her project partner Jenny Kröcher is studying the region on a larger scale. Using data from satellite images, groundwater and water level measurements, the geoecologist from ZALF is observing how humans have changed the water cycles of Lusatia over the last 30 years. All the data Kröcher needs for this is freely accessible. Her goal: »I am developing a method that allows me to show how the water cycle is changing without the need for complex models,« explains the scientist. »Most importantly, I want to show that this is also possible in Lusatia, where water levels are significantly affected by open-cast mining and agriculture.« What the geoecologist has discovered about evapotranspiration is particularly interesting. »On agricultural land in particular, I can see that evapotranspiration is increasing earlier in the year than it did 30 years ago,« she says. Climate change means that the growing season is starting earlier, and plants are therefore beginning to transpirate water earlier too. »At the same time, I can observe that evapotranspiration declines much earlier in the year—as early as June,« Kröcher continues. Her conclusion: The water availability to plants is already insufficient in early summer. Standard aerial photograph (left) and thermal image (right) of an agroforestry field in Lusatia. The thermal image shows differences in heat radiation across the area. In agroforestry systems, this can be used, for example, to investigate the shading effects of the planted trees. 25