Creating new farm roads under Department specs

When we think of farm infrastructure, we often think of animal housing, handling facilities and milking equipment.

As a country that bases its livestock model on utilising grazed grass, farm roadways are the connective ribbons that link up the paddock system that we so favour today in Ireland across beef, dairy and sheep enterprises.

The inclusion of farm roadways was a welcome addition to TAMS III, with a reference cost of €24.90/linear metre given. The reference cost is irrespective of the road width and whether own machinery or materials are used or not.

Key design criteria

A well-designed, carefully built and properly maintained farm roadway system has many benefits, including reduced lameness, better general animal health, faster and easier movement of stock, greater grass utilisation due to increased paddock access and the prevention of run-off to dry ditches or watercourses.

For dairy farms, additional benefits include reduced levels of mastitis, cleaner cows and lower SCC. For better herd management, consideration can be given to widening the road at the entrance to the farmyard in the form of a Y shape to improve movement of livestock and reduce dunging.

With the maintenance of roads close to the farmyard (a high traffic area) a difficult task, the Department states that concreting a section of the roadway close to yard is “sensible”, although this can create issues surrounding lameness.

Small stones dragged on to the concrete from gravelled areas can be pushed up into the cow’s hoof, as the only give between a cow’s hoof and a concrete road will evidently be the cow’s hoof.

For this reason, the sweeping of the concrete area to ensure it is free of stones, or adding a kerb to encourage stones to drop off cows’ hooves may be required.

While it may not always be possible, the positioning of new roadways adjacent to watercourses should be avoided.

However, where a new farm roadway runs adjacent to a stream, a fence on both sides of the roadway shall be erected to ensure livestock cannot access the water.

Construction

All topsoil and soft material should be excavated per Department guidelines, to a minimum depth of 150mm or down to a solid stratum, with the excavated material suitably disposed.

New farm roadways shall be laid in good weather when soil conditions are dry, primarily to ensure that the roadway material does not mix or get pressed into soft soil where a geotextile membrane is not used.

The finished level of the roadway shall be above the level of the field, otherwise drainage will be on to the roadway instead of off it.

A total of 200mm to 300mm of fill material should then be applied, with the necessary crossfall installed in the fill material to ensure an even distribution of the surface layer (50mm of fine material).

The fill material should be compact rolled to prevent the mixing of it and the surface layer, with the surface layer then rolled after being laid.

Removing water off the roadway quickly will extend the life of the surface and reduce the cost of maintenance mainly through removing the likelihood of potholes developing.

To remove water quickly from roadways they should slope to one or both sides, with a slope of 1:25/ 2.3° recommended.

A roadway that slopes to one side is easier to construct.

However, livestock flow is generally better on roads that have a gentle camber from the centre to each side.

Where there is a risk of runoff in to any watercourses, the cambering of slopes from the centre of the road must not be adopted, with the camber to be constructed that soiled water is directed towards the field and not the watercourse.

Slope

Roadways on steeply sloping ground can be subjected to a stream of water running the length of a section of roadway during heavy rainfall, which can damage the surface of the road through removing finer material and exposing the rougher aggregate underneath.

In this situation, angled ramps (to prevent buildup of soiled water on the roadway), shallow channels or cut-off drains at intervals across the roadway will divert water off the road before it builds up volume and momentum that could possibly be damaging.

The width of roadways depends on the number of livestock in the herd. Guidance on standard sizes is given in Table 1. The fence should be positioned about 0.5m from the edge of the roadway. This will allow livestock to utilise the full width of the roadway while at the same time prevent them from walking along the grass margin.

Dairy farms using automatic milking systems (AMS) or robotic milking can ignore this table as cows will not travel in the mobs typically seen with conventional milking.

A cow track in the grass margin usually means that the fence is too far from the roadway edge, and/or the surface of the roadway is too rough.

Cows should be evenly spread out across the working width of the road when being moved, being allowed to move at a steady pace.

The Department recommends the using of a geotextile membrane between the road materials and the soil, although it is not a requirement.

A geotextile is a synthetic, porous fabric used to separate the foundation layer from the ground underneath.

It prevents the base stones from becoming mixed with the soil and vice versa, helping to keep the roadway foundation material clean and free-draining for an improved upper road surface.

Farm roadways, particularly those in frequent use by machinery, can suffer considerable deformation in use and the role of the geotextile in this situation is to provide physical support, as well as separation.