Is your farm sulphur deficient?

Courtesy of her presentation at the Dairy Innovation Day, AFBI (Agri-Food and Biosciences Institute) soil scientist Dr. Suzanne Higgins said that all of Northern Ireland is a sulphur-deficient region.

“Deficiencies of this nature can lead to yield reductions of up to 30%. Grass testing prior to harvest will quickly confirm if silage swards are sulphur deficient,” she added.

I would strongly recommend the inclusion of sulphur in all fertilisers used on grassland. A dressing of 30kg/ha will be sufficient to cover an entire growing season. But its impact will be discerned most clearly on first-cut silage yields.

Higgins confirmed that all grass swards need a ‘phosphate boost’ in the early spring as a means of kick-starting plant growth-rates. This is because soil-bound phosphorous is not readily available at that time of the year.

“The most effective way of achieving this is through an application of slurry,” she added.

“A soil pH of 6.0 is the optimal value for grass growth. In cases where soils are acidic, high-quality ground limestone should be applied at the recommended rate. This will be determined by way of a soil test.

Lime should be applied at three-yearly intervals in order to maintain soil pH levels at their most appropriate value.

Higgins confirmed that nitrogen is the main determinant of grass yields.

“But it can be quite easily lost from the soil,” she said.

This is why it is so important that application levels are spread evenly across the growing season.

Work at AFBI has confirmed the benefits of using a protected urea source, when it comes to applying nitrogen. This new technology works to inhibit ammonia volatilisation throughout the warmer, summer months.

AFBI’s Dr. Debbie McConnell highlighted the ways by which dairy farmers can get more milk from grazed grass.

“There is growing evidence that producers can apply more nitrogen to their grassland areas, as a means of upping production,” she explained.

“In cases where less than 140kg of nitrogen is sown per hectare, it has been shown that an economic response of €11.60 will be generated for every €1 invested in additional fertiliser.

The extra nitrogen must be spread throughout the growing season and best use must be made of the additional grass that is produced.

According to McConnell, each additional tonne of grass dry matter produced per hectare will improve margins by €385/ha.

“There is a capacity to achieve over 10t of grass dry matter per hectare across all the dairy production systems practised in Northern Ireland,” she concluded.