Climate researchers point out that we must expect significantly more frequent, longer, and more intense periods of drought in the future. The ClimGrassEco project, in which we investigate the consequences of climate change with higher temperatures and CO2 concentrations for grasslands, takes this into account. Within the framework of this elaborate field experiment, we have the opportunity to create artificial drought under controlled conditions by equipping some of the experimental plots with rain canopies, thus preventing precipitation for a specific duration.
Drought in agriculture is difficult to describe because its impact results from the interplay of many factors. These include primarily a lack of rainfall combined with high temperatures, shallow and sandy soils, south-facing locations, and the type of vegetation. To cope with drought stress, plants have developed survival strategies that prevent complete desiccation and, depending on the duration, range from a slowing or cessation of growth processes to the death of plant parts.
The thermal imaging photograph, taken with a drone over an uncovered area with sufficient water supply (top) and plots subjected to several weeks of drought stress under a rain shelter (bottom), shows clear temperature differences. Higher temperatures in the covered plots indicate that the stressed plants are reducing their transpiration to conserve water, thus preventing adequate cooling of the leaf surfaces. This results in stunted growth and a significant yield reduction.
These and many other observations within the framework of the ClimGrassEco research project will provide insights that offer a sound basis for early adaptation measures to climate change.
