Following last year's variable growing season, and a prevailing wind of milk price cuts, grassland farmers face challenging decisions this spring on input costs. However, Philip Cosgrave, Yara's Country Grassland Specialist, emphasises that strategic spring nitrogen management offers the most cost-effective route to maximising forage production. And that "cutting fertiliser applications risks leaving significant grass growth potential untapped."

Whilst last autumn delivered favourable growing conditions, forage pressure is still acute for many farmers with already depleted stores. "There are a lot of farmers under pressure with short forage windows," Philip explained. "We need a kind spring to get grass growth going as early as possible, allowing earlier turnout and reducing pressure on silage requirements."

The false economy of delaying nitrogen applications

With milk price reductions, dairy farmers are inevitably looking at their break-even costs and fertiliser often seems an obvious saving. However, Philip warns against this short-term thinking. Spring-applied nitrogen typically delivers returns exceeding 10kg of grass dry matter per kg of applied nitrogen. With fertiliser nitrogen costing approximately £1.30 per kg and purchased feed around £280 to £290 per tonne, home-grown grass represents substantially better value. 

"Fertiliser is going to produce cheaper feed than buying in that feed," Philip emphasised. "The same principles apply across all grazing systems. Beef suckler operations benefit from early turnout to reduce housing costs and forage consumption. Sheep farmers approaching lambing require adequate grass to support ewes' milk production. Timing may differ by location, but the fundamental principle remains: applying nitrogen when soil conditions permit accelerates grass supply rather than waiting for visible growth."

Farms leaving over 0.5T/ha of grass growth behind

In Ireland, recent research by Teagasc (Ireland's national body for agriculture and food development) revealed significant untapped potential. Their analysis shows the spring target through to late April is 2.5 tonnes of grass dry matter per hectare. However, farm averages reach just 1.8 tonnes – with even top performers achieving only 2.2 tonnes. So many farms leave between half a tonne and a full tonne of potential growth unrealised. "Most of that opportunity is down to grassland management and nutrient supply, particularly getting nitrogen on at the appropriate time," Philip believes.

Strategic application: dividing the farm into thirds

Again, with cost control in mind Philp recommends targeted rather than blanket applications, with nitrogen initially applied to the fields most likely to respond early. 

"The first third should comprise free-draining lighter soils, south-facing fields, and recently reseeded leys. Apply when soil temperatures reach 5.5 to 6 degrees and are climbing, provided conditions are suitable," he advises. Depending on stocking levels, Philip suggests application rates should be 20 to 30 kg N per hectare. 

"If you take a product like YaraBela NUTRI BOOSTER, which is our can-based nitrogen with sulphur product, you're looking at applications somewhere between 80-120kgs per acre. For fields requiring phosphate, products like YaraMila EXTRA GRASS at 27-5-5 deliver the necessary boost."

Addressing common misconceptions on clover

More recent research from Teagasc is reshaping how farmers should manage clover-containing swards in the critical spring period. Contrary to common assumptions that artificial nitrogen and clover don't mix early in the season, the evidence now points to a different approach. 

Farmers should manage perennial ryegrass swards in the same way, whether they contain clover or not, right up until May. This means applying the same nitrogen rates to both pure grass and grass-clover mixtures during spring. The research demonstrates that applying higher levels of nitrogen in springtime doesn't negatively impact clover performance from May onwards, when growing conditions become more favourable.

"Without these spring nitrogen applications, farmers risk running into lower grass supply exactly when demand is highest," says Philip.  "The key message from the research is clear: don't differentiate your spring management based on clover presence."

Organic manures: maximising slurry value

With cost-savings still in mind, Philip suggests slurry and parlour washings also contain valuable nitrogen for kickstarting growth. Early application maximises nitrogen value as reduced temperatures minimise ammonia losses. For NVZ farms, organic manure applications become permissible from early February. 

Wastewater represents another often-overlooked nitrogen source, particularly effective on paddocks with higher covers closed earlier in autumn. However, organic manures typically require topping up with artificial nitrogen to deliver optimal response.

"Don't miss the application window"

Last year's early Spring highlighted the dangers of buying fertiliser late with some farmers hit by logistical delays and missing critical application windows. Philip has three recommendations to ensure farmers can plan to maximise grass production this spring without stretching resources.

"Securing sufficient fertiliser now for first and second applications ensures readiness when conditions allow spreading," he advises. "Secondly, apply nitrogen earlier than traditional timing, monitoring soil temperatures and prioritising the most responsive fields first. Thirdly, recognise the superior economics of home-grown forage, with typical response rates exceeding 10 kg dry matter per kg of applied nitrogen. This is where the value in applying fertiliser is. With pressure on margins and forage stocks, strategic spring nitrogen management offers grassland farmers cheaper feed than buying it in."