Last week, I visited a number of the farms in the Teagasc Heavy Soils Programme in Limerick and Kerry. A number of observations jumped out. The investment in drainage can be significant in terms of money and time. You need to know what you are doing and have a plan. Some farmers told me that, in the past, they have invested a lot of money and, within a short number of years, the paddock has reverted to where it was with little or no improvement.

The cost of the drainage does not guarantee success. Just because it’s expensive does not mean it is the right thing to do or that it’s going to work. You need a plan that will be site-specific for your farm. There may well be soil type issues that will strongly influence the type of drainage you complete.

You can also argue that spending €2,500 to €3,000 per acre beside your milking parlour can potentially release a lot more money for you than a purchase of €5,000 per acre 15 miles over the road. The message is if you can get away with a spend of €500 per acre for the right job, why spend €2,500 on the wrong design which might not work.

A clear example of the above cost and option dilemma faced John Leahy, a dairy farmer based near Athea in west Limerick. John is a demonstration farmer in this project and five acres of his farm has been drained and is now being measured for success.

He dedicated a paddock to the trial across the road from his parlour that was simply growing rushes three or four foot high in recent years. He still has some paddocks like this. In the past, John has got little use from the land, maybe using it as a holding paddock for a few weeks in the summer but getting no productive value from it.

Last year, he dug deep collecting drains across the paddock, linked these up with gravel moles and reseeded. The cost was significant at €2,800 per acre.

I walked across the paddock after heavy rain last week and it’s fair to say he could have let his milking herd on it. It had been grazed and was actively growing a good crop of lush green grass. Yes, it’s early days, but the transformation has been a complete reversal. Part of the control plot in the paddock was not drained and the land was very wet.

Outside the ditch, John had a number of paddocks where he had drains at the sides of the paddock but, in these paddocks, with his own 13t excavator, he simply had turned down the top soil profile so that he had a harder, more trafficable layer of soil on top. These paddocks were also sound underfoot and were actively growing.

As poorer subsoil was now on top of the profile, they didn’t look as rich or productive but they were also a lot better than the field of rushes they replaced. I asked engineer Pat Tuohy, who is leading the Heavy Soils project with James O’Loughlin, for his opinion as I was walking across the paddock that had been ‘turned’.

He said: “No outflows have been created to allow water to leave the paddock. In fairness, we can’t discount this and the cost is about half of what we spent in the trial paddock. However, there is a school of thought that this could revert to its previous state sooner rather than later. We will monitor with interest.”

Expensive

Clearly, the most expensive job might not be the right job and this project aims to try and differentiate the best options. A number of other points also jumped out from our visit.

Remember, if you buy an excavator and do a lot of the work yourself, you need a lot of time on your hands to drive the machine. Dairy farmers generally don’t have that kind of spare time. Yes, you can buy the driver time but factor that into your investment at €80 to €100 per day. Factor in the soil fertility cost and maintenance of the soil fertility and drainage in the overall plan. Spending large amount of money and not getting soil fertility sorted out is pointless. A good farm roadway is essential if you want to make the most from of these ryegrass pastures.

James O’Loughlin explained that Teagasc, in association with Kerry Agribusiness, Dairygold Co-op and Tipperary Co-op, is holding farm walks on four of the seven Heavy Soil farms at different venues around the country starting next week.

The objective of the programme is to increase the profitability of farming on these heavy soils by increasing grass production and utilisation. The average grass production (t DM/ha) on the seven farms in 2011, 2012 and 2013 was 10.6, 7.8 and 10.3, respectively. The reduced grass production in 2012 highlights the huge effect the wet summer of 2012 had on pasture growth on these farms.

Two significant factors were identified as limiting grass production and utilisation on these farms: (1) low level of soil fertility (P, K and pH) and (2) poor drainage infrastructure on these naturally poorly draining soil types. A programme has been put in place in each farm to increase soil fertility to recommended levels.

James said that, on each of the seven participating farms, two hectares of land were identified to be drained. The soil type ranged from peat to carboniferous shale to red sandstone till.

After site investigation, the most appropriate drainage solution was selected. A range of drainage systems were installed over the seven farms which included deep drains (1.7m), shallow drains (0.9m), mole drains and gravel mole; additionally, ripping was carried out where necessary.

All of this work was carried out last summer, when conditions were ideal. The effectiveness of these drainage systems is being monitored using modern water flow technology.

A series of farm walks are planned to showcase the work done on four of these farms. Land drainage, soil fertility and the farm business will be discussed. These events are open to all farmers and qualify as a BTAP event for beef farmers.

21 May: 11am

John O’Sullivan milks 102 cows on a 71ha farm (20ha leased) 2km from Castleisland, Co Kerry. The farm has poorly structured heavy-clay subsoil with poor permeability. It is located in an area of high annual rainfall (1,300mm average). There has been considerable investment over the years in farm infrastructure.

A main drain with eight lateral collector drains at 20m spacings was installed on a 2ha paddock last year. Gravel mole drains were installed on half of the paddock and deep ripping in the other half.

22 May: 11am

John Leahy milks 90 cows on a milking block of just under 40ha outside the village of Athea in west Limerick. The average annual rainfall is 1,320mm.

The farm has a mixture of heavy mineral soil and some peat over carboniferous shale.

Open water courses were deepened, a spring tapped and collector drains at 20m spacings were installed on 2ha last year. Gravel mole drains were then installed.

28 May: 11am

Tom and TJ Ryan (pictured) are a father and son partnership who milk 70 cows at Rossmore near Dundrum in Co Tipperary on 50ha (14ha rented). The soil is a heavy, silty, clay loam with poor permeability.

The average rainfall for the area is 982mm. Deep drains at 1.7m were installed to exploit a permeable layer located at a depth of 1.5m to 1.7m. These drains were dug in two stages. The first metre was dug with a 60cm wide bucket and the lower 70cm was dug with a narrower tile drain bucket; this was to prevent the collapse of the drain during excavation which could happen by using the narrow tile drain bucket alone.

An 80mm drainage pipe with 60cm of stone was used and the drains backfilled.

29 May: 11am

Danny Bermingham milks 100 cows at Mountrivers, Doonbeg, Co Clare on 67ha (44ha owned). There are two soil types on the farm: peat and a heavy clay soil which is poorly structured, very dense and with poor permeability. The average rainfall for the area is 1,185mm. Open water courses were cleaned and deepened collector drains 0.9m deep and 15m apart were installed and mole drains pulled on 2ha of the clay soils last year.

Ready Danny Bermingham’s My Farming Week here.