Sustainable phosphorus management of horse paddocks at Julmyra
Julmyra Horse CenterPhosphorus lossesPhosphorus accumulationEutrophicationHorse paddockOutdoor horse keepingHorse manure management
Horse keeping is gaining an increasing interest in Sweden. During 2004 to 2010 the number of horses increased
with 10 - 20 %, and was estimated to be 362 700 in 2010. Julmyra Horse Center (JHC), situated in Heby municipality,
is a gated community for people sharing a large interest for horses and a vision of a sustainable horse
management has been formulated. This study evaluates how the horse keeping of today at JHC, and how an
expansion of the horse keeping may affect the risk of enhanced phosphorus load to the nearby lake system
Vansjön ? Nordsjön. The risks associated with outdoor horse keeping are an accumulation of phosphorus in the
soil profile caused by dung deposition and roughage residues, and treading damages, that might contribute to
eutrophication. The soils in the area are mainly lowland soils with high humus content. The mineral fractions are
dominated by sand, sandy loam and moraine. There are no regulations regarding livestock densities for outdoor
horse keeping in Sweden, but maximum 2-10 horses/hectare is recommended in order to retain a vegetation
cover in paddocks. The livestock density at JHC today is 17.5 horses per hectare, causing treading damages in
most paddocks. The paddocks receive approximately a yearly input of 38 ? 53 kg P/hectare with the current
horse density. The soil phosphorus status in most of the paddocks (P-AL) was low to moderate, 4.2 ? 7.9 mg/100
g soil. However, in areas where an accumulation of phosphorus by dung deposition had occurred over a long
period of time, and for a loose housing system the P-AL values were higher (17.7 and 16.3 mg/100 g soil). In
these areas, the values of phosphorus sorption capacity in the soil were low or moderate (1.1 and 4.5) and the
degree of soil phosphorus saturation quite high (up to 22.0 %). It was concluded that there is a continuous accumulation
of phosphorus in the horse paddocks which is not sustainable in the long-term. In order to make the
paddock management at JHC sustainable suggested countermeasures are increased paddock areas, cleaning of
dung and roughage residues and establishment of grass vegetated buffer strips between paddocks and the watercourse.