This is a subscriber-only article
Grass growth on David Hunter’s farm near Newtonstewart, Co Tyrone stood at 15.3tDM/ha last year, over double the Northern Ireland average of 7.5tDM/ha.
Speaking at a LacPatrick event on David’s farm on Wednesday, Dr Debbie McConnell from AFBI said that results from Agrisearch’s GrassCheck project show that annual grass growth of 10tDM/ha is achievable on NI farms, regardless of farming system and land type.
Host farmer David Hunter runs 75 dairy cows in a spring calving, grass-based system. The herd averaged 6,150l/cow at 4.04% butterfat and 3.39% protein from 1.5t concentrates last year.
The target for David is 6,000l from 1t of meal. This would deliver a milk from forage value of 3,778l, which is more than 2,000 litres higher than the NI average.
Host farmer David Hunter.
David started milking cows on his farm six years ago, initially running a mixture of Holstein and Friesian cows. He has since started to use Jersey semen and is moving towards a cross bred herd.
Lime
Visitors to David’s farm were told that applying lime to correct soil pH is the first and most important step to improving soil fertility.
Dr Debbie McConnell pointed out that 50% of grassland soils in NI are below pH 6 and she said that an increase of over 1tDM/ha in annual growth can be achieved by increasing soil pH from 5 to 6.5.
Recent soil analysis for David’s farm shows a pH range from 5.8 to 6.7, with an average value of 6.3.
2017 trends
Damien McAllister from DLF Seeds said that the higher soil pH paddocks on David’s farm grew more grass last year.
Presenting figures for the top performing paddocks on the farm in 2017, McAllister said that the best grew 18.6tDM/ha and had a pH of 6.7, whereas growth ranged from 15.4-17.6tDM/ha in three paddocks that all had a soil pH of 6.1.
“All paddocks had the same soil fertility and the same amount of nitrogen applied. I am not aware of any difference in land type because they were all grazed the same number of times,” McAllister said.
However, he said that pushing soil pH above 6.5 can potentially lock up copper in the soil. McAllister advised farmers to carry out a broad-spectrum soil analysis to find out the level of molybdenum and other micro nutrients which can have an impact on this.
SHARING OPTIONS: