Reseeding is essential for healthy sward
Farmers know the value of reseeding, but the amount of ground reseeded any year largely depends on the weather.
Reseeding was back by about 50% in 2012, while it was normal in 2011, and up 40% in 2010 following two years of bad weather.
Very little seeding was done in the spring of 2013 but fine autumn weather allowed farmers almost make up for the spring deficit.
Seed prices are high, at €70 to €80 per acre, but slightly lower than last year. According to Dave Barry of Gold Crop, there is a good supply of top varieties available.
Poor spring weather is again putting pressure on reseeding opportunities, but it should be carried out where necessary.
Teagasc surveys indicate that many pastures are producing 50% less than their potential.
Based on Moorepark research, there is huge variation in grass dry matter production on farms. There is up to 50% difference between farms and 60% within farms, and the key factor is the level of perennial ryegrass within pastures. Of course, poor soil fertility, soil type, and management will also significant-ly reduce grass production, as well as utilisation. Over 60% of soil samples are deficient in P, K and lime.
Not only will pastures with low ryegrass content produce poorly, but they will be 25% less responsive to nutrients. The response to fertilisers is also reduced by low lime status.
Most of the differences in production between pastures are in the early part of the year. up to May.
With high production costs, reseeding pastures with a low level of perennial ryegrass has become more important than ever. Farmers cannot afford to buy unnecessary large amounts of concentrates to supplement poor grass and silage, or to apply fertiliser on poor pastures that give a poor response.
The extra costs associated with reseeding vary from €200 to €250 per acre.
The extra grass output should be up to 1.5 tonne of dry matter (7.5 t of grass) per acre, per year, which is worth over €200 per tonne.
In addition, the reseeded pasture is much higher quality, and grows earlier in the year. Assuming you maintain the reseeded pasture in a highly productive state for 8 to 10 years, reseeding is the best investment a farmer can make.
If on the other hand you allow reseeds to revert to poor weedy pastures in a few years, reseeding is not worth it. The botanical composition of the existing swards and the management of the grassland after reseeding should be the main influencing factors in justifying the cost of reseeding. The demand for extra feed on your farm is another factor.
Young, germinating seedlings need a ready supply of fertiliser and lime. Ideally, you should soil test which should be taken after ploughing.
In general, reseeds should get three bags of 18.6.12 or 10.10.20 per acre at sowing, and more nitrogen if required after a month, except with high-clover based pastures.
With minimum cultivation systems, always apply at least one-and-a-half tonnes of lime per acre, to counteract the acidity of decaying material on the surface.
Whether you use ploughing or minimum tillage, a fine, firm seed-bed is essential for a good performance. Clover seeds in particular are often covered too deep and are lost. Good rolling is essential.
New reseeds should be monitored closely for pest attacks, such as from slugs, leather jacket, frit fly and rabbits. Post-emergence weed control, usually after five to six weeks is essential.
Seedling docks and thistles are easily killed at that stage; if they are allowed to develop, they will cause problems during the life of the reseed. If clover is important, use a clover-safe spray such as Legumix DB. The main weeds in the reseeds should be identified before choosing a spray, because some sprays have little effect on certain weeds such as chickweed.
Post-emergence spray will not permanently kill docks growing from established roots; that is why pre-spraying with Glyphosate is so important.
