County Armagh dairy farmers are being encouraged to use the autumn period to assess underperforming grassland, with DAERA warning that reseeding and overseeding could play an important role in future farm profitability.
The advice comes in a DAERA article published on 16 September 2026. It highlights the work of McCarragher and Sons, members of the Armagh Dairy Business Sustainability Group, who are pictured spreading lime in County Armagh.
Grass remains the foundation of profitable milk production on Northern Ireland dairy farms. However, its productivity and persistence can decline as weeds, poaching damage and less productive grass species become established.
Wilson Marshall, a dairy adviser with the College of Agriculture, Food and Rural Enterprise, said autumn offers farmers an opportunity to examine grassland performance and carry out work intended to improve future forage production.
“Timing is critical when carrying out grassland improvement work,” says Wilson.
According to the guidance, early autumn can provide favourable conditions for new grass to establish and grow before colder weather arrives. A useful benchmark is to reseed about 10% of the grazing platform each year.
When reseeding or overseeding may be needed
Fields with less than 70% perennial ryegrass should be assessed for improvement, particularly where weed levels are rising, weed grasses have become established or sward density has fallen. Grazing records and grass-measurement data can help identify fields that are restricting overall farm productivity.
A full reseed is not always required. Overseeding may be a more cost-effective option where a sward remains reasonably productive but contains poorer-quality grass or areas damaged by poaching.
“The success of overseeding depends largely on achieving good seed-to-soil contact and reducing competition from the existing sward,” explains Wilson.
The article advises tight grazing before sowing, followed by light harrowing and rolling where appropriate. Overseeding is most likely to work in open swards with enough exposed soil for seed-to-soil contact, while slot-seeding equipment may be more suitable for denser swards.
Ryegrass overseeding commonly uses about 10kg of seed per acre. Seed and sowing costs typically range from £55 to £80 per acre, depending on the mixture, seed rate and contractor charges. Farmers may also need to budget for lime, fertiliser, weed control and other field operations.
Results will vary according to soil fertility, the condition of the existing sward, establishment success and subsequent management. Fields with less than about 50% perennial ryegrass, substantial deterioration or significant weed burdens may be better candidates for a full reseed.
Soil fertility is central to establishment
A full reseed requires a larger initial investment, but it can create an opportunity to establish modern perennial ryegrass varieties with improved yield potential, digestibility and persistence. Better grass production can reduce the need for purchased feed and support milk production from home-grown forage.
Before undertaking either type of grassland improvement, farmers are advised to assess soil fertility. DAERA Soil Nutrient Health Scheme results, where available, should be considered alongside routine soil analysis carried out at least every four years. The tests help determine soil pH and phosphorus and potassium status.
DAERA’s guidance says farmers should aim for a pH of about 6.3 on mineral soils and between 5.5 and 5.8 on peat soils. Phosphorus should be maintained at Index 2 and potassium at Index 2-, in line with soil-analysis recommendations.
Lime is described as one of the most cost-effective inputs where pH is below target. Raising acidic mineral soil from pH 5.5 to 6.3 can increase grass production by at least one tonne of dry matter per hectare each year, although the response depends on soil type, organic matter and management. The additional grass may be worth about £60 per acre annually.
Restoring soil pH can also improve phosphorus and potassium availability and may release up to 60 units of nitrogen per acre each year from soil reserves, potentially reducing the need for purchased fertiliser.
Measuring returns from better grass
Farmers are encouraged to use grass-measurement software such as Agrinet alongside regular plate-meter assessments. Monitoring can identify weaker fields and allow farmers to compare annual grass production before and after renovation.
That comparison can help determine whether reseeding has delivered a return on investment and ensure future budgets are directed towards fields where the greatest gains are possible.
Variety choice is also important. Farmers should consider seasonal growth, digestibility and persistence, and select mixtures suited to grazing, silage or a combined system. DAERA recommends using independently evaluated varieties included on recognised recommended lists.
White clover is increasingly being included in reseeding mixtures to improve forage quality and support biological nitrogen fixation. Where clover is used, soil fertility and nitrogen fertiliser applications need particular attention.
With feed and fertiliser costs continuing to affect dairy profitability, DAERA says productive grassland remains a cost-effective investment. It also points to Northern Ireland’s climate as a natural advantage for grass production.
“Improving grassland productivity will help farms reduce costs, improve resilience and support long-term profitability while making better use of our greatest natural resource,” concludes Wilson.
Farmers who have not completed Soil Nutrient Health Scheme training can still attend courses delivered by Countryside Services Ltd or complete CAFRE’s online programme at a time and pace to suit them.