Equine manure storage and management plans

The Règlement Sanitaire Départemental (RSD) is currently the overarching text in France which imposes hygiene and health requirements upon all equestrian and equine establishments, regardless of the number of animals housed there. The location and distances for manure storage as well as the rules on spreading are described in the sheet on Rules for the storage and spreading of horse manure.
The construction of a manure storage area must be considered according to the number and type of horses housed with bedding, the accessibility required to handle the manure (manual, tractor and transporter) and in compliance with the rules in terms of impermeability and distances from third parties.
Horses are usually accommodated in the following conditions:

• individual accommodation in boxes,
• daily cleaning of about 8-10kg of straw/day/animal,
• a feed ration consisting of dry fodder and concentrates.

When the box is cleaned, the manure has a dry matter content of 35 to 65%, corresponding to very compact manure. Despite its characteristics, horse manure is not exempt from the obligations around short-term storage on an impermeable platform where any run-off can be recovered.
Regardless of the frequency of cleaning (daily, weekly), it is essential to store the manure:
on an uncovered platform with a back-slope with a gradient of 3 to 7%;
or on an uncovered platform which includes a pit for collecting run-off;
or on a covered platform with a back-slope.

The DeXeL method was developed by the Institut de l'Elevage (Idele) in collaboration with the Institut Technique du Porc (ITP) and the Institut Technique de l'Aviculture (ITAVI) and was approved by the Comité National de Suivi du Programme de Maîtrise des Pollutions d'Origine Agricole.
“The DeXeL software is the result of a collaboration between I-CÔNE and the Institut de l’Elevage. It is used by most technicians who carry out the preliminary studies provided for by the PMPOA (Programme de Maîtrise des Pollutions d’Origine Agricole). A technical committee of users participates in the definition and evolution of the software. It is made up of specialists in building and agronomy from the Chambers of Agriculture, Cooperatives and Design” (see www.i-cone.fr/Products/Dexel).
The reference document “Calculation of storage capacities for ruminant, equine, pig, poultry and rabbit effluents” (September 2018 version, in French) is updated annually (see idele.fr/services/tools/pre-dexel.html). Storage capacity is expressed in m²/animal for a minimum of two months’ storage. The surface area for at least two months’ storage is the regulatory capacity prescribed by the French Nitrates Directive.

The reference tables are established for a single purebred horse (stallion, mare or gelding). These references take into account the loss of volume due to the maturation of the product over time.
For a single horse, the surface area of a manure storage area with three walls for one month’s storage is equivalent to 1 m²/animal.
Where it is necessary to take into account different animals, the following reductions are applied:

Pluviometry

It is also necessary to take into account the rainwater that collects on uncovered areas of equine waste and to calculate the volume of run-off to be stored in the sealed pit according to (P-ETP) and the storage duration for:
•    brown water in uncovered exercise areas,
•    rainwater on uncovered ancillary surfaces,
•    leachate on the manure storage area.

For the uncovered pit and other uncovered surfaces, see the P and ETP references in “Rainfall on Pit: ref Part II, paragraph 2.1” in Calculation of storage capacities for ruminant, equine, pig, poultry and rabbit effluents” Idele, September 2018, in French

Note that:
•    If a mechanical manure removal system is used, the manure pile can be up to 4.50m high, with an average height of 1.50m.
•    In the case of manual removal, the average height of the pile is around 2.00m.
Ask for a diagnosis of the compliance of manure storage facilities using the “pre-DeXeL” tool developed by the “building” department of your local Chamber of Agriculture.

An alternative to creating a manure storage facility is to use skips which are periodically removed from the facility. The skips must comply with the same impermeability regulations as a manure storage facility (RSD).