Unlocking the potential of heavy soils dairy farms
Improving soil fertility, grazing infrastructure, grazing management and herd genetics are key priorities in the Teagasc Heavy Soils Programme. James Dunne Teagasc Dairy Knowledge Transfer Specialist tells us more.
One common question when dealing with farms which are of moderate to poorly drained soil status is: “Does my focus need to be different given the fact I have a heavy farm?” This sentiment often hinders progress and leads to inefficiencies.
The Teagasc Heavy Soils Programme (HSP) over the past decade has shown that the fundamental management practices to achieving farming success on these soils are similar to those on free-draining soils. However, they require adjustments to take account of prolonged periods of wet weather and poor grazing conditions.
Key lessons
At the outset of the programme the primary focus was land drainage, but it soon became obvious that although targeted land drainage would make up part of the solution, at individual paddock level it was a combination of management practices that would play a significant role across all the farms. This involves improving soil fertility, grazing infrastructure, grazing management and herd genetics.
Correcting soil fertility
As part of the programme, a soil sampling campaign was undertaken to monitor soil fertility status. All paddocks on the participating farms are now sampled annually. Soil sampling has shown that most HSP farms are below optimal soil fertility levels. The sampling interval and intensity has allowed soil fertility to be addressed on a paddock-by-paddock basis.
Lime and fertilizer application strategies have been developed with a focus on the under-performing sections of each farm. Increasing soil fertility on these soils brings particular challenges in terms of nutrient response rates. An intense regime of data over an extended period. Targeted nutrient improvement measures across the HSP farms has seen them move from a position where in 2013 only 2% of paddocks were optimum for pH, P and K to the current figure of 30% for this measure.
There remains a lot of room for improvement – a major issue with building soil fertility status on such soils is a disparity in responsiveness to applied nutrients or lime. Regular soil sampling means nutrient allowances can be targeted at the most responsive farm areas to ensure best return. Soil fertility improvements have delivered a large part of the increased grass grown on each farm. HSP farms on average have increased grass grown from 10.6T DM hectare in 2011 to 12.5T DM hectare in 2022.
Increasing grass utilisation on grassland farms is a key driver in increasing net profit. Improved grassland management relies upon robust grazing infrastructure; collection at a paddock scale in terms of nutrient inputs (chemical/organic fertiliser, concentrates) and off-takes allows for an in-depth understanding of changes in soil nutrient levels when compared with annual soil tests suitably sized and shaped paddocks with multiple access points serviced by roadways of sufficient quality and adequate drinking water.
On heavy soil farms, grazing infrastructure is particularly important to maximise grassland utilisation during periods of wet weather. Appropriate roadways, paddock access and water trough provision allows for a flexible approach in terms of grazing allocations and aggressive on/off grazing where required.
Farm audits
The HSP farm audits were carried out by each farmer along with HSP staff and aimed to identify any issues around grazing infrastructure under the following headings: paddock size, shape and access points; extent, quality and condition of the farm roadway network; access to drinking water in paddocks.
A number of issues around grazing infrastructure were apparent on all farms. Many of these were relatively minor in their own right, but combined to create difficulties in grassland management and utilisation, animal performance and labour input, particularly in periods of poor weather and difficult grazing conditions.
Farmer focus: James McMahon
James McMahon has seen his herd’s milk performance increase substantially since joining the Teagasc Heavy Soils Programme, he farms near Swans Cross in Co Monaghan, joined the Heavy Soils Programme (HSP) in 2015. He currently milks 115 cows on a 28-hectare milking platform while farming 79 hectares in total. “The farm is not only heavy in nature, but is also fragmented which has its own challenges,” explains James.
The farm performance wasn’t where he wanted it to be from an animal and grassland performance perspective. After he joined the HSP, a plan was devised to correct soil fertility, improve grazing infrastructure, identify paddocks for land drainage works, and also improve herd genetics and fertility performance. “Along with the HSP team we put in place a long-term plan for the farm which I have been working on over the last number of years,” says James.
On grazing, he placed a strong emphasis on improving the soil fertility status. This has improved dramatically, but continued work is required to ensure the percentage of paddocks optimised for pH,P&K continues to increase. For grazing infrastructure, additional main roadways and spur roadways have been added. And fences have been amended to allow multiple access points into individual paddocks. “If you can’t get to the paddock easily you just won’t get cows to grass on those wet days.”
Soil analysis and classification from the HSP team identified that a shallow drainage system was required in the form of collector drains and gravel mole drainage. “Unfortunately for me, this is the most expensive form of drainage but it is working very well in the parts of the farm where I have completed it,” says James. “We try to complete 2.5/3 hectares a year and then also incorporate this into our reseeding programme. We grew 12.8T DM/Ha in 2022 which we are very happy with and it’s reflected in the animal performance improvements.”