The important contribution that regular liming makes to soil health and climate resilience was a key takeaway from the first Lime Symposium organized by Vereinigte Kreidewerke Dammann (VKD), an Omya joint venture, in January 2025. Experts from the Universities of Hannover, Kiel and Osnabrück joined agricultural advisors from state institutions and private organizations, as well as from trading partners and agricultural trade advisors to discuss the need for reliable solutions to soil fertility and plant health issues, particularly in the light of increasing challenges caused by climate change.
Acid soils can have a devastating impact on soil structure, nutrient availability and crop productivity, yet many growers continue to suffer their consequences without taking action. According to the 2018 Thünen Report, 42% of arable soils and 57% of grasslands in Germany suffer from excess acidity, which could be alleviated by regular liming. As Dr. Michael Dreyer, CEO of Agro Counseling Dreyer, explained, "An optimal pH improves nutrient uptake and stabilizes soil structure, which enhances production input efficiency, boosts water retention, and supports higher yields and crop quality.”
Prof. Dr. Stephan Peth from Leibniz University Hannover agreed, emphasizing that proper pH is vital for maintaining soil structure. His research, using X-ray tomography, reveals how changes in soil structure are affected by pH adjustments. Dr. Tina Frank, Agroecology and Soil Science expert at the University of Osnabrück joined the discussion, explaining, "Lime promotes the formation of stable soil aggregates, optimizing air and water balance and creating better conditions for soil organisms like earthworms."
It is the calcium in lime that has such an advantageous effect on soil structure. The calcium ions improve soil flocculation, binding clay particles and organic matter together to form aggregates. These factors contribute to greater resilience against extreme weather conditions like drought or heavy rainfall. Well-limed soils are less prone to nutrient leaching, especially nitrogen, and are also less susceptible to wind and soil erosion or compaction.
Prof. Dr. Ute Kropf from Kiel University of Applied Sciences showed that calcium not only benefits the soil but also plant health and productivity. Her long-term trials demonstrated that fields with regular lime applications produced higher yields and healthier crops, especially barley and sugar beets. She explained that calcium contributes to disease resistance through its role in cell wall stability.
To maximize liming benefits, Kropf offered the following practical tips:
- Incorporate liming regularly into the crop rotation, using stubble lime applications, or by applying lime at the end of winter in areas with high rainfall
- Divide fields into sub-areas for more efficient lime application based on soil sampling
- Choose liming materials carefully, avoiding high-magnesium limes on wet soils
- Test calcium saturation if soil calcium levels appear inadequate
- Monitor soil structure regularly and consider loosening compacted soils.