Leibniz University Hanover: Force Measurement and Research with ZwickRoell on the Growth of Plant Root Tips
Case Study
- Customer: Leibniz University Hanover, Institute of Earth System Sciences, Department of Soil Science, Chair of Soil Biophysics
- Location: Hanover, Germany
- Industry: Research Institute & Academia
- Topic: Penetration resistance in soils depending on root exudates and soil moisture
January 2025
The Institute of Earth System Sciences at Leibniz University Hanover simulates the growth of a root in soil. Root tips of plants release substances known as mucigel into the soil, which can influence the subsequent growth of the roots. With support from ZwickRoell, the university investigates how this process is affected by the soil’s water content and what forces the roots develop.
Institute for Earth System Sciences at Leibniz University Hanover
The Institute of Earth System Sciences (IESW) at the Leibniz University Hanover was founded in 2024 and is an important interdisciplinary institution that combines several previous institutes, including Soil Science, Geobotany, Geology, Mineralogy, Physical Geography and Landscape Ecology. The aim of this restructuring is to intensify cooperation between different specialist areas and to promote research into the complex interactions between humans and nature.
A central concern of the IESW is the investigation of the effects of global change, particularly with regard to climate change, the loss of biodiversity and the sustainable use of resources. The Institute pursues an integrative approach that incorporates both scientific and social perspectives in order to develop solutions to pressing environmental issues. In addition, the IESW is promoting the creation of a joint geocampus, which facilitates the exchange of students and researchers and strengthens interdisciplinary teaching. Through innovative research projects and practice-oriented study programs, the institute offers a platform for aspiring scientists aiming to address the challenges of our time.
The task
Measurement of forces during simulated root growth
The impact of soil moisture on the effect of mucigel on the forces required for root growth is largely unexplored. Researchers were therefore faced with the challenge of designing a completely new experiment to simulate the growth of a root. This required a compression test with adjustable measurement speed, where position and applied force could be measured at short intervals with high accuracy.
The ZwickRoell solution
Compression test with stainless steel penetrometer needle
The growth of the root was simulated by pressing a penetrometer needle into the prepared soil samples at a defined speed. A specially manufactured stainless steel tip (based on the root geometry of a plant) was pressed at a defined speed into homogeneous soil samples with different combinations of mucigel and water content. The researchers used a ZwickRoell AllroundLine (Z100) materials testing machine. From the resulting forces, penetration resistances and energies required for root growth were calculated and the influence of mucigel and water content quantified. Thanks to the wide range of possible test speeds, the best possible variant could be selected with the help of a preliminary test, which provided realistic results with optimized measurement duration. The measured forces formed the basis for calculations and analysis of the investigated factors.
“With the ZwickRoell testing machine, we discovered that the plant's mucigel is particularly helpful for root growth when the conditions are most challenging for the root. Specifically in dry and clayey soil. In short: we simulated the growth of a plant root in the soil and measured the resulting forces.”
MSc Ulla Rosskopf, PhD student at the Institute of Soil Science, Leibniz University Hanover
The result
Soil moisture is of crucial importance
The influence of mucigel on the force required for root growth depends on the prevailing soil moisture. In fine-grained soil (clay), mucigel reduced the energy required for root growth under dry conditions, while it slightly increased in moist soil. These effects were significantly less pronounced in a coarser-grained soil (sand).
Click here to access the publication in the scientific literature.
