Soil is a Natural Water Reservoir – Potassium Supports Retention
The potassium increase trial in Halle (Saale) is actually one of the oldest ongoing long-term trials on potassium increase in Germany, launched by Karl Schmalfuß in 1949. One of the location’s research projects focused on demonstrating the connection between potassium application and water use efficiency.
The trial compared two variants of potassium fertilization (0 kg K2O and 240 kg K2O), showing that the field capacity, and therefore water retention capacity of the soil had been raised by 9%. At a soil depth of 30cm, this corresponds to 90.000l ha-1 of additionally retained water, or 9mm precipitation.
Potassium influences soil stability, due to precipitated potassium salts, significantly increasing the soil’s water retention properties. The precipitated potassium salts cause bridging between the soil particles, reducing the size of the macropores and increasing the soil’s water retention capacity.
Potassium is therefore not only essential for yield production, but also has a sustained effect on the soil’s water retention.
This project is funded by K+S KALI GmbH; practical research is conducted by working groups from the Halle, Gießen and Kiel universities.