Good soil health is one of the drivers behind strong grassland results. Hannah Park reports.
Discussions around making the most of forage are increasingly coming to the fore, but with weather conditions seemingly hitting both ends of the extreme in recent months, pressure to do so is arguably increasing.
Successfully managing soil health to its optimum is one driver behind good grassland results and was the topic in a recent Yara-organised technical forum in which experts weighed in on specific strategies for improving soil nutrition.
Yara analytical specialist Jon Telfer said farmers needed to make sure their soil was working for them, with analysis key to a grass crop realising its potential.
Mr Telfer said: “Soil is a farm’s biggest asset and healthy soil is the foundation for higher yields and quality on-farm. Tools such as soil health analysis and mineral analysis can ensure it receives the input it requires.
“Testing does not just mean laboratory measurements though. Regular field assessments, checking soil structure and removing any compaction, checking drainage and noting soil biology are among other important actions.”
Many farmers, he said, were not managing grassland to its full potential.
He said: “Following a review of a large group of UK soil samples tested at Yara analytical services, more than half of those tested below the target pH of 6.
“We need a shift in mindset towards treating grass like a crop and, to get more out of fertilisers, we need to get on top of our soil pH.”
Mr Telfer suggested any discussion on soil health should start with pH levels.
He said: “Soil pH affects the availability of all nutrients required for plant growth and impacts particularly on three main drivers of grass yield: N; P; and K.
“There is a direct relationship between the supply of nutrients and the expected rate of grass growth, which is why careful note should be taken of the P and K index soil test results fall into.
“Deficiencies will cost dry matter yield and, if left untreated, will continue to get worse year-on-year. Equally concerning though from an environmental perspective, in terms of the risk of runoff and so on, is the one-in-10 soils which demonstrate excessive levels of phosphate. Agronomically there is no benefit here from further applications.”
Mr Telfer also spotlighted sulphur among the ‘many secondary and micronutrients’ which have role in successful grass growth.
According to figures from the UK national atmospheric emission inventory, reductions in atmospheric sulphur meant about 90 per cent of UK soils were sulphur deficient in 2016.
He advised a nitrogen to sulphur ratio of 12:1 for optimum grass yield and quality, but results from several thousand samples tested by Yara showed two-thirds had a nitrogen to sulphur ratio higher than this.
He also advised getting slurry and manure samples done, as although a key on-farm asset, both were an unpredictable material subject to change in-line with external factors such as rationing, weather and how they were applied.
Mr Telfer said: “Knowing nutrient content precisely will improve slurry use efficiency, in terms of spreading where it is most needed, but could also reduce bagged fertiliser requirement and will result in far better predictably potential of grass growth rates.”
With a revised water framework in England now in force, since 2018, which states any land receiving organic or bagged fertiliser must have a nutrient plan and up to date soil samples in place [no older than five years at the time of application], Mr Telfer advised that to stay compliant, farmers should soil test 20 per cent of their farm every year.