It is potential to reduce fees or eradicate nitrogen fertiliser functions with out having a serious detrimental have an effect on on grazed grass progress. Nonetheless it ought to be achieved on the right time and on acceptable fields.

Many producers may be tempted to tug once more on fertiliser this season in mild of escalating nitrogen (N) prices. Nonetheless, merely halving utility fees would possibly probably see a 20-25% low cost in grass progress.

In its place, it may be extra sensible to reduce or stop N at certain cases of the season, says neutral soil and grassland specialist Chris Duller.

In doing so, the grass progress dip may be lowered, whereas moreover lowering the annual fertiliser bill.

See moreover: Decisions for lowering bought-in fertiliser on livestock farms

Fertiliser trial

In 2020, Mr Duller carried out a trial at Mountjoy, a Farming Be part of demonstration farm in Pembrokeshire, to evaluate the have an effect on of lowering N within the summertime and autumn.

The farm’s common worth was utilized for the first 4 grazing rounds – the first had no N, then fees of 30, 30 and 20kg N/ha (12, 12 and 8kg N/acre) had been utilized.

From July to October, grass each acquired no N, 18kg N/ha (7kg N/acre) or a half worth of 9kg N/ha (3.5kg N/acre) for each of 4 grazing rounds.

By not making use of any summer season season or autumn N, full N use for the 12 months lowered by 50%, whereas full grass progress dropped by merely 10% (see desk beneath).

When a half worth of N was utilized within the summertime/autumn, there was a 6% low cost in grass progress for 25% a lot much less full N all through the season.

Fees on grazing ground

Mr Duller advises in opposition to lowering N fees dramatically on silage ground as this may occasionally reduce yields and compromise manufacturing. He suggests the subsequent on grazing ground:

1. In the reduction of N firstly of the season

Look to reduce N functions in February-March when N response fees are lower.

Avoid making use of N to poorer ground that will have a lower response paying homage to north-facing fields or these with a low pH or compaction. In these cases, do not apply N until soils are warmth.

On good fields, N fees will probably be lowered by 5 or 10kg N/ha (2 to 4kg N/acre).

Mr Duller says even these producers with a extreme spring grass demand can drop once more, nevertheless by no more than 5 or 10kg N/ha.

2. Be careful for missing out on peak grass progress

Stick close to full fees by May and June so grass manufacturing is not going to be compromised. Proper now of 12 months grass measuring is necessary – if farm covers are above aim there may be options to cut once more on N.

3. Drop N from July

By this time, there has already been a build-up of residual N from muck and urine from grazing cows.

Any clover has moreover begun to restore N. Purpose high-quality leys with good soils and/or clover for zero nitrogen utility presently.

4. Do not decrease N an extreme quantity of on poor ground

Complete elimination of N on swards with solely 30-40% perennial ryegrass and with no clover should often be prevented.

“These will are inclined to stop totally if we don’t feed them,” Mr Duller says. In its place, drop once more by about 5-10kg N/ha (2-4kg N/acre).

5. New leys nonetheless require full worth N

Do not decrease N on new reseeds as they ship the simplest response to N and you will compromise effectivity.

Impression of halving or halting nitrogen functions from July to October (Mountjoy, Pembrokeshire 2020)

  No summer season season N Half summer season season N Full N
Complete N utilized 80kg N/ha (32kg N/acre) (sooner than July) 119kg N/ha (48kg N/acre) 158kg N/ha (64kg N/acre)
Share of full N utilized in season 50% 75% 100%
Worth saving/ha July-September versus full worth N utility (34.5percentN@£650/t) £147/ha (£59/acre)

(£1.88 x 78kg N/ha)

£73/ha (£30/acre)

(£1.88 x 39kg N/ha)

Complete kilos of dry matter produced all through season 14,365kg DM/ha (5,813kg DM/acre) 15,012kg DM/ha (6,075kg DM/acre) 15,978kg DM/ha (6,466kg DM/acre)
Share of full dry matter manufacturing potential 90% 94% 100%

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