Lime is required on up to 65% of dairy farms, the statistic is a major concern as land is the new quota, according to Teagasc’s Mark Plunkett.
Speaking at Teagasc’s Soil Fertility Conference in Clonmel recently, the Teagasc soil fertility specialist said the majority of Irish soils have a lime requirement.
According to Plunkett, analysis of over 100,000 soil samples shows that lime has become a limiting factor on both dairy and dry stock enterprises, which is having a negative impact on soil fertility and production.
“Lime is required on up to 65% of dairy farms, it is a major concern for these farms as land is the new quota, 69% of dry stock enterprises have a lime requirement.”
Plunkett added that lime is the starting point for successful soil fertility management.
“We aim for a pH of 6.3, we have a lot of soil below this target and there are only 10% of soils with good overall fertility. Lime is the starting point.
“Grassland farmers should start thinking like tillage farmers and start thinking about grass off-take.”
Despite the relatively high number of soil samples taken on an annual basis, Plunkett highlighted recent research which indicates that only 40% of these samples are used for agronomic use.
“We are actually good at a taking soil samples, there are 100,000-120,000. Only 40% of the samples taken are used for agronomic use.”
Soil Phosphorous and Potassium
Like lime, a large percentage of farms are also lacking Phosphorous (P), with 55% of soils currently sitting in Index 1 and 2, said Plunkett.
The Teagasc specialist added that there a lot of Irish soils with a P level below the recommended Index 3.
“There has been a steady increase in soils below index 1 and 2, this has been a limiting factor for grass production.”
However, he added that there has been some improvement since 2012.
According to Plunkett, Irish soils tend to have a good level of Potassium, however, in 2009 Potassium (K) usage dropped by 50%, but it has slowly started to return back to 2006-2007 levels.
Soil test results show that there has been a decline in soil fertility from this nutrient from 2008-2011, but this trend has stabilised in recent years, he added.
Plunkett added, that this drop probably occurred as a result of silage harvesting.
Soil Sampling
According to Plunkett, soil sampling is relatively good value for money and it costs in the region of €0.50/ac/year.
“Soil sampling is a small annual cost and it costs in the region of 50c/ac/year. It is the first step in fertiliser planning.”
These results were generated from samples from nearly every parish in the country, he said, and there are approximately 120,000 soil samples taken on an annual basis on Irish farms.
Plunkett added that soil sampling equips farmers with specific information to make the right decisions on farms.
“Up to date soil samples allows the farm to track soil fertility over time.”
