A rest home for retired horses, The Paardenkamp Foundation, wishes to contribute to circularity. It is exploring the possibilities to process and apply horse manure with straw on the own farm.
At the moment, solid horse manure is exported from the farm to be used elsewhere as mushroom substrate and liquid dairy manure from a nearby dairy farm is used for fertilization of the land.
The following alternatives were studied:
- using horse manure for fertilization,
- composting of horse manure,
- fermentation and anaerobic digestion of horse manure.
The end products differ in physical and chemical characteristics, e.g., application methods for solid and liquid manure products, nutrient levels in the products and gaseous emissions from processing and land application. Also the survival rates of pathogens such as parasites and worms and degradation rates of veterinary medicines may vary between the different technologies.
It is concluded that adherence to the current working method (the replacement of horse manure with dairy manure for fertilization of the land) is the best compromise between circularity, soil fertility, animal health and economy of De Paardenkamp.