Improving grass production on Dairylink farms
29th August 2015
Dairylink adviser Conail Keown highlights the importance of reseeding and examines how one project farmer is managing the task.
One of the key targets for all Dairylink Ireland project farmers is to increase grass growth capacity on their farm.
Every project farm situation is unique in terms of varying soil type, local climatic conditions, stocking rates and the management capabilities of the particular farmer.
The impact that these factors have on both grass growth and the quantity of grass utilised still remains to be seen on all the project farms, where grass measurement is currently taking place.
On average, only 7.5t of grazed grass is utilised per hectare on Irish farms, but data from the best commercial and research dairy farms indicate that this can be increased significantly.
With grass clearly the cheapest feed available, increasing growth and utilisation will result in improved farm profitability.
Research and analysis from Teagasc profit monitor and PastureBase Ireland has illustrated that by increasing grass utilisation by 1t/ha, net profit can be increased by £190/ha (€260/ha).
A key driver for increasing grass growth capacity on project farms is the weekly measurement of grass cover and the subsequent use of online grassland software to analyse grass production data. This provides the basis for the decisions made on Dairylink farms.
Soil fertility management
Soil fertility is critically important for grass growth. Approximately 90% of soil sampled in Ireland is limited in one of the three major factors that affect soil fertility – pH, phosphorus (P) and potassium (K). Soil samples taken on Dairylink farms show that 55% of soil was found to be deficient in either pH, P or K.
The ideal level for grass growth is pH 6.3, as this maximises the availability of nitrogen (N), P and K.
Applying lime to increase soil pH will increase nutrient uptake and therefore DM yield. It will also improve the long-term persistency of perennial ryegrass in the sward.
Recent research from Moorepark illustrated that lime applied at a rate of 5t/ha to soil with pH 5.3 increased grass production by 1.5t DM/ha in the following two years. Research has also highlighted soils with P and K at index 3 (index 2 based on NI soil analysis) will grow approximately 1.5t DM/ha per year more grass than soils with index 1.
Upgrading soils with poor fertility status is essential for the future of milk production in order to allow farmers to fully capitalise on the cheapest feed available to them.
Farmer focus
David Brady, Stradone, Co Cavan
Newly reseeded areas on some Dairylink farms have established well this year due to ideal growing conditions.
David Brady, based in Stradone, Co Cavan, reseeded 10% of his grazing platform recently, but heavy rain after completion of the reseeding disturbed the seedbed.
However, David has since patched the areas that were worst affected and the reseed is now looking good.
David’s key reason for the reseed was lack of productive perennial ryegrass in the old swards and research has illustrated that swards with low proportions of perennial ryegrass are costing farmers up to £250/ha (€342/ha) per year due to the loss of grass DM production and reduced nitrogen utilising efficiency.
If the cost of reseeding is estimated at £600/ha (€822/ha), the increased profitability of the reseed would cover the reseeding cost in just over two years. It is for this reason that reseeding is one of the most cost-effective investments dairy farmers can make.
Three paddocks on the Brady farm were completely reseeded this year.
Before the plough moved in, the field had new drains installed and old drains were improved. David also took the opportunity to tidy hedgerows and to fix paddock entrances and the areas around water troughs.
David has used alternative reseeding techniques on the farm in the past, but has found that the best results are achieved when the plough is used, as this seems to aid drainage on the farm.
The old swards were killed off with glyphosate before the ploughing.
Grass seed was selected to suit the soil type (heavy and wet). David used late-heading diploid varieties at a rate of 14kg/acre.
He is now planning a post-emergence spray to control docks and all other weeds, which will be applied approximately six weeks after establishment, which will be just before the paddock’s first grazing.
David said: “Management of a new reseed through spraying and grazing is critical on the farm and I consider it equally as important as the method used to reseed in the first place.
“Early grazing allows light into the base of the plant to encourage tillering and I will graze these paddocks with the cows if conditions allow.
“However, given the late stage in the year and current ground conditions, these areas may not carry cows and I may well use young stock for the job.”
The first grazing of a new reseed can be completed at a pre-grazing yield of 600kg to 1,000kg DM/ha (2,100 to 2,500kg DM/ha total cover).
Frequent grazing of the reseed at low pre-grazing yields during the first year of establishment will benefit the sward. The aim is to produce a uniform, well-tillered, dense sward.
If possible, a reseed should not be closed for silage in the first year of production, as the shading effect of heavy covers of grass will inhibit tillering of the grass plant, resulting in an open sward, which is liable to weed establishment.
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