Raising soil pH levels by one index point to 6.5 can increase grassland production by 30%.
Independent grassland specialist Charlie Morgan told farmers attending a Farming Connect Master Grass course that soil pH is the main driver for nutrient uptake, with the greatest availability to the plant at index 6.5; below this and there is a sliding scale of reduced performance.
He urges every farmer to make rebalancing low pH levels a priority. “A plant can only fully access nutrients at the correct pH, you will get optimum production from grass and clover swards grown at the correct pH.’’
Mr Morgan led workshops at Master Grass, a Farming Connect initiative to help beef and sheep producers become better grassland managers. A similar course for dairy farmers was held at Gelli Aur College Farm, near Llandeilo.
He says only 30% of recent soil samples taken in Wales are at the correct pH level.
Rainfall depletes lime reserves as does the application of nitrogen and sulphur, which increases acidity.
Mr Morgan, of grassland consultancy GrassMaster, recommends applying lime in early spring or autumn because dry summer conditions will result in lime particles sitting on the grass leaf; winter applications risk runoff.
He says potash and phosphate levels are also extremely variable across Wales; potash is often deficient on silage ground while grazing land can have too much of both minerals.
“If we don’t feed the soil, we don’t feed the grass, and the result is no feed, or more expensive feed, for livestock.
“Farmers must consider the potential of their soils and how they can convert nitrogen into something they can sell.’’
But many farmers are unaware of what base they are starting from because they don’t test their soils.
Soil testing can cost as little as £10 a field and provide farmers with information on pH, phosphate, potash and magnesium levels.
Once these are known, a nutrient management plan can be developed to properly apply nutrients generated on-farm and to calculate precisely how much manufactured fertiliser is needed to balance these, Mr Morgan advised farmers attending the course at Glynllifon, a Farming Connect Innovation Site near Caernarfon.
He regards soil testing as the best tool farmers have for planning profitable fertiliser applications.
“Farmers could not just potentially be saving a lot of money on their purchased fertiliser costs but they could be better using the resources they produce on farm, their slurries and their manures, which should also be tested to establish their nutrient content.’’
Mr Morgan advocates that sheep and beef farmers test their soils every five years and dairy farmers every three years; fields that have no testing programme in place are likely to be under-performing, he warns.
“A dairy farm will burn a third of a tonne of lime in every acre each year, a sheep farm half of that,’’ says Mr Morgan.
In situations where pH, potash and phosphate levels are below target, leys will be dominated by species including Yorkshire Fog and creeping bent.
With a difference of 10 D-value points between these and high quality species such as perennial ryegrass, it can make the difference between a grazing or silage quality of 10ME instead of 11.5ME.
“For potash, every index point below 2 is potentially costing you about 20% of your dry matter, and the nitrogen applied is not utilised to its potential,’’ says Mr Morgan.
Without adequate phosphate, plants won’t develop root structure.
The nutrient requirements of the soil and the amount that can be supplied by manures and slurries should be calculated before deciding what fertiliser to buy. “It might be quite different to what has been done before,’’ Mr Morgan suggests.
Once soils have been tested, a nutrient management plan should be put in place. “Farmers get their soils tested but don’t understand the results and therefore don’t adjust their traditional inputs. A nutrient management plan will give them that information.’’
In Wales, farmers registered with Farming Connect are eligible for between 80 – 100 per cent funding for a nutriment management plan.
The chemical composition of the soil is only partially useful if the physical structure is good.
Compaction has become an issue on many farms after months of rain.
“You can have a perfect chemical analysis but if soils are damaged and compacted, nutrients are not necessarily getting access to the root structure,’’ says Mr Morgan.
Soils need the chemical, physical and biological status of soils to work in harmony, drawing together correct nutrient land flora and fauna levels and the right soil structure, he adds.
“Always carry more animals underground than on it – I was once told that the tonnage of livestock carried is governed by tonnage of soil biology. If you haven’t got a healthy population of bugs there is nothing to see the soil.’’
Master Grass is a series of dedicated courses run by Farming Connect to help Welsh farmers hone their grassland management expertise.
The courses provide farmers with practical skills and confidence to implement changes on their own farms.
There is a focus on selecting and establishing appropriate grass species and varieties for intensive rotational grazing, grazing infrastructure, soil management and measuring and interpreting grass growth measurements.
Dewi Hughes, Technical Development Manager at Farming Connect, says with this knowledge farms could improve their milk yield and liveweight gains from grazed grass and forage and reduce overall input costs.
Carmarthenshire beef and sheep farmer Ben Anthony, who set up a rotational grazing system for his sheep flock last year, says he would now be converting more of his fields into paddocks because the course had given him confidence to do that.
He had learned that water provision was as important as grass quality and quantity in this system.
“It’s not all about the grass, we will plan more carefully where we place troughs,’’ says Mr Anthony, of Frowen, Login.
“It was just one of many points the course taught me, over and above the basics I would have learned at a farmer meeting.’’
This project has received funding through the Welsh Government Rural Communities - Rural Development Programme 2014-2020, which is funded by the European Agricultural Fund for Rural Development and the Welsh Government.