Kintyre livestock and crop farmer Duncan Macalister of Glenbarr Farms near Campbeltown has a message for Scottish farmers; get to know the type of lime being applied on your fields to maximise its impact. Lime is not only a soil neutraliser but also a soil conditioner, and if you do not pay attention then soils can become imbalanced. By changing the type of lime used, Duncan has added nearly one ton of barley output per acre.
The story starts following Duncan’s studies at SAC Craibstone in Aberdeenshire between 1983 and 19847. After the formal education, Duncan went on to work abroad in New Zealand then back in Scotland on farms in Morayshire and down the east coast of Scotland.
Then in 1994 Duncan returned to work on the farm at home and set about implementing some of the good practices he has witnessed on his travels. At the time the farm was running 100 Blue grey sucker cows and 1000 purebred Blackface ewes.
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One of the first challenges at home was the huge number of dockens on the farm. The soils had been turning acidic over the years and the slurry store for the suckler cows was acting as a ‘massive docken factory’. Even 30 years ago the chemistry was not very potent to destroy docks without damaging the clover in the sward.
Duncan noticed that docks were less of an issue on arable farms where a crop rotation kept the ground clean.
He said: “The ground which was in cereals for a number of years got rid of the docks beautifully, so I decided to grow a bit of barley here in Kintyre. It made financial sense too, as we are 150 miles from the central belt which puts £30/t on feed coming in which means today feed barley is over £200/t and straw £140/t. The haulage cost is never going to go away, so we try to produce as much as we can on the farm. We are now at a place where we are more or less self-sufficient, our biggest bill is the fertiliser.”
To tackle the docks Duncan decided to grow four years of spring barley to clean the ground. But in the sand-based soils on the farm, Duncan couldn’t get his barley to perform. He explained: “I couldn’t get it to grow, the soil was sticky. Between 45% and 50% of the soil is sand and wouldn’t expect a drainage issue. The end rigs were not growing well. The ground wasn’t draining like a sandy soil should, when it rained puddles would appear on the ground.”
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The pH in the soil was correct and the fertiliser application was 75kg an acre The barley would get 1.5t per acre and maybe touch 2t/acre in a good year. The land had the ability to perform well with ten to 12 tons of fresh weight silage regularly taken at the first cut and six to eight on a second cut. It would have been ploughed every 10 to 15 years and then reseeded with a castle hill long-term mixture.
Duncan said: “Looking around the area I could see other farms performing better on similar ground. And their crops always grew to the edge of the field, whilst mine was thin, spindly, and poor. I think at the time we were using the feed barley variety Tyne which has been proven to work.”
For a few years, Duncan kept trying to work out the issue with a turning point occurring after he took part in the monitor farm programme. Duncan signed up to be a monitor farmer in only its second round of operation in 2011. The monitor farm programme paid for soils expert James Bretherton to look at the ground to assess ways to improve it. Through soil sampling, James discovered that there was a slight magnesium and calcium imbalance, with too much of the former. The higher magnesium alongside the silt, sand, and clay in the soil meant that the ground had the ability to set like concrete when it rained. If the magnesium levels were lower the particles within the soil could move apart and the porosity of the ground would increase significantly.
Duncan said: “It was a bit of a eureka moment when we worked out that it was high levels of magnesium that had made the soil stick and claggy.”
Once the issue had been identified the next step was working out how the magnesium levels have become too high on the farm. Duncan was always keen to ensure pH levels were correct for growing grass and crops, with the use of granular lime. The choice of lime was always based on the cheapest neutralising value which is common practice on many farms. As a result, magnesium lime from Durhum was the best value to bring the pH up. However, the lime was also applying too much magnesium to the soils and a calcium lime was needed to redress the issue. This type of lime was being produced locally at Campbelltown but was more expensive neutralising value.
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Duncan said: “There was also a lot of concern about staggers in cattle at the time with low magnesium soils triggering more cases on the farm. So adding magnesium to the soil was seen as a win-win. When you compared our magnesium levels on the SAC technical notes we were within the guideline amounts. But you could see the ground was puddling much more than it should.
“To solve the problem we switched to calcium lime from Campbelltown which is 92% calcium and only 2% magnesium. It was what most of the local farmers were using.”
Duncan is keen to stress that farmers should know the type of lime they are buying and the levels of calcium and magnesium.
“You need to know the percentages of magnesium and calcium,” he explained. “Lime is a soil conditioner as well as a neutraliser. We shouldn’t treat it as only sorting the pH but also the help the soil structure.”
Duncan also believes that little and often applications of lime is best for the land. “I put on at most 2/t per acre but prefer to be 1.5t/acre for each application,” he said. “In the 1940s when they started using lime here, they were putting on 0.5t/acre of calcium lime with a horse and shovel. I believe little and often is the way to go.”
Due to the change in the soil, Duncan now aims for a yield of 2.5t to 3t per acre in a good year. But this year isn’t looking like a record at the moment. The Skyfall spring barley has a significant amount of regrowth following a dry June, which Ducan admits is very unusual weather for the west.
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As the weather patterns change on the farm with rainfall nearly doubling over the last 40 years alongside hot and dry periods Duncan is a believer in ensuring healthy soils to maximise resilience. This was recognised at the Royal Highland Show when Duncan won the Scottish soil competition run by the James Hutton Institute.
“Every soil is every farmer’s problem. Soil is the engine room for your farm. It is where everything stems from, buildings, machines, and even animals are secondary to getting your soil right,” he concluded.
FARMING SYSTEM
The current crop rotation starts with a crop of stubble turnips going into a grass field followed by four years of spring barley then back to grass again. The field will then be eight to ten years in grass before returning to crop. Annually the farm grows between 130 to 140 acres of spring barley with most of the grain and straw used for the cattle.
The farm runs 650 cross ewes. and 150 Aberdeen Angus and Hereford spring calving cows in a Black Baldy system. The progeny is finished off grass in their second summer at 18 months with some supplementary grain added towards the end. The heifers, steers, cows with calves, and sheep are all grazed separately on the farm in a rotational system.
Duncan is passionate about his rotational grassing which believes significantly raises output on the farm. He believes that a well-run rotational system is the equivalent of adding 25% more acres onto your farm.
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