If you are going to spend money on land drainage, you need to make sure that you are doing it right. This was the general consensus at the recent Aurivo drainage farm walks in Mayo and Donegal.

In the first of a series of events held by the Aurivo Farm Profitability Programme, in conjunction with Teagasc, the focus was on growing more grass and grazing it at the shoulders of the year.

Two Aurivo suppliers hosted the farm walks – the Walsh family, based near Knock, Co Mayo, and the Hastings family, from Lifford, Co Donegal.

Jarlath and Danny Walsh, Knock, Co Mayo

Dairy farmer Jarlath Walsh introduced the farm, with Mayo Teagasc adviser Brendan Garry outlining the need for the 43ha milking block to produce at maximum capacity and increase grassland production and availability for grazing. Milking nearly 120 cows in two milking platforms, father and son Jarlath and Danny want to improve the underperforming land.

The crossbred herd produced 440kg of milk solids (MS) per cow in 2013 (5,400 litres).

Soil fertility is generally good and able to support the grass demand from the milking platform, with 90% of the farm at Index 3 for phosphorus.

The Western Drainage Scheme installed many drains on farms in the 1980s and while many of these have broken down due to heavy machinery use, stock damage and the movement of drains in peaty soils over time, there are several gravel mole-type drains still working 25 years later.

The main Walsh grazing platform is working well, with good-quality grass and soil fertility, hence the decision to focus on improving the more difficult land.

The most fascinating thing about this farm walk is that, in the difficult land, in an area of no more than 10 to 15 acres, there were three drainage issues occurring: normal springs popping up, broken-down mole drains and soil compaction. It is clear from the advice given during the walk that not only do drainage systems differ from farm to farm but various issues arise within the farm paddocks.

The springs obviously need to be tapped and perhaps more mole drains should be installed. Jarlath and Danny decided that the first step in their project was to maintain the existing open drains and then use the land drain flusher to clear out the buildup of ‘‘red’’ iron deposits in underground pipes.

Test pit

Teagasc land drainage specialist James O’Loughlin said: “The natural follow-on from this is to dig a test pit in a problem area to examine the soil profile and investigate what’s happening in the layers we cannot see from the surface.”

Jarlath and Danny decided to make some land improvements last year, with the plan to address the paddocks in a step-by-step approach. Financially, a step-by-step approach is the most sustainable way to take on such a project. The land had consistent issues with waterlogging and was prone to damage by stock.

Jarlath and Danny drained the section using a gravel mole-type drainage system (shallow drainage) before reseeding the area. They installed collector drains at 20m spacings and then linked these together with gravel mole drains at 1.7m spacings.

At the end of the tour, it was highlighted by Danny Walsh that, although drainage is a major project, it is important for them to remember why they are doing it – to grow more grass. He further outlined that, post-drainage, paddocks are often tender and need greater care.

Wesley Hastings,

Ballindrait, Lifford, Co Donegal

The Hastings family is farming near Lifford, Co Donegal. They are milking 185 cows this year on 74ha. They produced an average of 552kg MS/cow (6,300 litres) in 2013 with their NZ Friesian herd.

The Hastings purchased an outfarm in 2013, which they use for rearing heifers and silage. The newly acquired outfarm has poor soil fertility, with phosphorus at Index 2.

The outfarm is dealing with soil compaction, a common problem shared by many of the farmers in attendance.

Local adviser Seamus Culhane examined the soil structures of the farm and demonstrated other soil types from surrounding areas, including brown earths, brown podzolics and gleys. In samples taken from the Hastings’ farm, and its surrounding area, it was clear that the roots from the grass were only penetrating 5in to 8in deep and all of a sudden stopping short, indicating soil compaction in the region.

In a shallow digger-made hole, Teagasc’s Frank Kelly indicated the effects of compaction on grass-growing abilities and how to tackle it with a sub-soiling machine.

Teagasc specialist Pat Clarke outlined the costs associated with taking on land drainage, with research indicating that it would cost between €5,000/ha and €7,000/ha for large-scale drainage. The message is to look at what you already have – can it be maintained?