A PROFIT from Grass conference held at Scotch Corner focused on the increasing role of forage crops in livestock production and offered delegates some tips on how to reduce soil compaction.

The growing global demand for food is expected to increase pressure on human-edible sources of food for animals, an effect which will lead to a greater role for forage crops in livestock production, explained Dr Debbie McConnell of DairyCo. Feed costs remain the biggest driver of profit and grass is still the cheapest source of food for ruminants, she said.

These factors combined mean it is vital for the industry to maximise the potential of grassland, but the percentage of milk from forage on dairy farms has been fairly static over the years, with some holdings even experiencing a decline. The GB average milk from forage figure for 1982 was 1,400 litres/cow, which represented 26 per cent of the total yield, with the figure for 2012 at 2,221 litres/cow, or 28 per cent.

The key to grassland management is getting the soil in the right condition and alleviating compaction is the most important element for growing a productive, high quality crop, said Dr McConnell.

“It is believed that about 70 per cent of our grassland soils are carrying some degree of compaction. Affected soils will typically hold 20 per cent more water, compared with healthy soils. This will reduce the amount of oxygen available to plant roots. In addition, nitrogen losses can be up to 40 per cent higher and the net result is a negative impact on grass yields. One solution is to aerate the soil, although care must be taken to minimise plant kill, if a slitter or sward lifter is used.”

When choosing between a sward slitter and a sward lifter, the slitter is appropriate for compaction up to about 10cms, with the sward lifter more suitable for deeper compaction. Comparisons of the two techniques have shown that autumn is the best time for soil aeration, as it allows the soil to ‘bed in’ over the winter. However compaction problems can be exacerbated, if aeration is carried out in unsuitable conditions. In fields where soils are aerated in the spring, some evidence of root kill has been noted.

l The meeting was organised by Mole Agriculture, Dow AgroSciences and Germinal Seeds