The impact of horse husbandry on eutrophication
There are around 350,000 horses in Sweden, which together produce large quantities of manure. Horse manure that is collected, handled and stored safely, and then returned to the agricultural sector, constitutes a valuable resource. Manure that is not properly managed risks leaching nutrients – phosphorus and nitrogen – into watercourses and ultimately contributing to eutrophication in the Baltic Sea.
Horse manure accounts for almost 20 % of the total amount of farmyard manure produced in Sweden. However, a large proportion of this horse manure comes from small horse farms that do not engage in agriculture, which means that large quantities of manure are not reused in crop production. Furthermore, 76 % of Sweden’s horses are located in urban areas or areas close to urban centres, where it is difficult to establish a functioning cycle for horse manure.
The contribution of horse husbandry to eutrophication has begun to attract attention, and some work is underway to encourage possible measures. However, there is a lack of data on the proportion of horse manure that is managed inadequately or not at all, the proportion that is managed safely and used as plant fertiliser, and scientifically grounded measures to minimise nutrient losses from horse husbandry. These knowledge gaps make it difficult for decision-makers, regulatory authorities and horse owners to take the necessary measures to minimise nutrient losses from horse husbandry and improve the utilisation of manure as a resource.
However, some knowledge does exist. As part of the Living Coast project, a series of simple measures were implemented in collaboration with a horse farm to demonstrate how nutrient leaching can be prevented. Horse manure can be collected, handled and stored safely using simple methods. One example of a very simple measure is to change feeding locations in the paddock, thereby reducing local wear and tear on grassy areas. A healthy paddock is much better able to absorb and retain nutrients than one that is trampled and muddy. However, many private individuals own small horse farms, and both horse owners and stable owners often have limited knowledge of the value of horse manure, the risk of environmental impact and possible measures.
The project The Impact of Horse Management on Eutrophication aims to generate new knowledge on how densely populated and trampled horse paddocks affect the aquatic environment. The project will also provide a scientific basis for motivating action on horse farms and for selecting effective and cost-effective measures.
The objective is to calculate losses of nutrients, nitrogen and phosphorus, from paddocks at five horse farms. The project will also conduct interviews with the horse owners at the farms regarding the horses’ time spent outdoors, how manure is managed and the farm’s feeding routines. Experiences, results and recommendations from the project will be compiled and disseminated to selected target groups.
The impact of horse husbandry on eutrophication is being carried out by BalticWaters in close collaboration with Stockholm University, Södertörn University and Swedish University of Agricultural Sciences. The project is funded by the Thuréus Forskarhem och Naturminne Foundation.
Project materials
SU: Horse farms can cause eutrophication (2024-01-12)
Scientific article: Managing multi-functional peri-urban landscapes: Impacts of horse-keeping on water quality (2023-11-20)
Workshop: the path to sustainable horse husbandry (2022-11-10)