In a previous project, we observed that the manure on one farm was unusually fluid and had low emissions of methane and manure gas (H₂S). This may be linked to the long-term addition of lime suspension to the manure. Our hypothesis is that the lime suspension enhances the breakdown of organic matter and leads to the release of ammonium and other compounds that inhibit methane-producing microorganisms. A lime suspension is very finely ground lime dissolved in water and with a dispersant agent added so that the lime stays liquid.

To investigate this further, we will conduct a survey among farms using lime suspension. In addition, we will compare methane emissions, manure gas, microbial composition, pH, water content, and chemical properties in six cattle manure storage facilities at Jæren—three with and three without the addition of lime suspension. Our partner Omya Hustadmarmor will assess whether the current dispersing agent used in the lime suspension can be replaced with an alternative approved for organic farming.