7 September 2001

Nfertiliser boost for grass?

SEPTEMBER fertiliser applications could offer a much needed boost to autumn grass growth, particularly for farms carrying extra stock.

Applying nitrogen fertiliser up to mid-September can increase autumn supply, according to Northern Irelands Department of Agriculture and Rural Development. Reseeds and swards with high perennial ryegrass content respond better to nitrogen applications of 40-50kg/ha (32-40 units/acre) than older swards, it advises.

But financial gains from applying fertiliser will decline after mid-September, says David Patterson of Greenmount College, Co Antrim. "There may be a case for applying fertiliser until Sept 20 in southern England, where it is warmer and there is less risk of heavy rainfall, but applications may present an environmental risk in northern regions."

Maximising grass quantity and quality is the key to getting the most from pastures, says Dr Patterson. "Growth rates are beginning to slow and are currently about 50-60kg DM/ha. Longer rotations are critical to maintain grazing for as long as possible."

Rotation length should be about 30-35 days at this time of year. Bringing in previously ungrazed areas or silage aftermaths can help extend the rotation, says Dr Patterson.

"Stock should also be prioritised. Lactating dairy cows or beef finishers should graze best quality paddocks, with other stock grazing areas not accessed by these groups."

As well as growth, grass quality should also be maximised, he advises. "Ensure swards are cleanly grazed or cut to clear the base before building them up. Lax grazing and then allowing them to grow for three to four weeks is bad news as far as grass quality is concerned." &#42