The Dutch government aims to reduce ammonia emissions to protect the environment, and the dairy sector is a major contributor. Farmers can lower emissions by reducing livestock numbers, modifying barn floors, or adjusting feed rations, but these options can be drastic or costly. Manure treatment offers an alternative without requiring barn modifications. Kopros, a microbiological product added to manure, reduces ammonia emissions by using microbes that convert ammonia into organically bound nitrogen, which limits volatilization. As a result, treated manure contains more organic nitrogen that is gradually released after field application through mineralization. This process reduces nitrogen losses to air and water and lowers the need for synthetic fertilizers. Kopros also contains plant growth–promoting microbes that may improve soil quality, crop growth, and the soil microbiome. However, its effects on soil quality, crop quality, and nutrient leaching have not yet been thoroughly studied, so this demonstration project aims to gain practical experience in grassland and arable farming and support future research.