So why should I reseed. Isn’t the field growing grass? Reseeding is extremely important to increase the productivity of any farm. The aim is to reseed 10-15% of your farm every year. While the best-performing farms can produce over 15t DM/ha, estimates suggest the national average level of production is just 9.1t DM/ha of grass. Research from Teagasc has shown that old permanent pasture produces on average 3t DM/ha/year less than perennial ryegrass dominated swards and are up to 25% less responsive to available nutrients such as nitrogen. High quality reseeds can deliver higher stocking rates, increased live-weight gain, faster regrowth’s, use nitrogen more efficiently and grow more grass at the shoulders of the year relative to permanent pasture. Grass quality and utilisation are also improved. At around €700/ha reseeding represents a significant investment but the returns are worthwhile. Reseeding will give you 3-5t DM/ha/year more in feed for livestock for 8 to 10 years before you need to reseed it again.
Reseeding can be carried out in either Spring or Autumn, with Spring reseeding being preferable. In Autumn soil conditions deteriorate as the year progresses, lower soil temperatures can decrease seed germination and variable weather conditions reduce the chances of grazing the new sward or applying sprays for weed control. If sowing clover it is important to sow earlier in the year as it takes up to 10 weeks for it to establish properly. Spring reseeding is ideal due to Increasing soil temperatures and sunshine which help improve grass/clover establishment. Opportunities to graze the reseed several times over the summer months allows the sward to tiller meaning the following spring the sward will be of higher quality than a reseed carried out in the autumn.
If you feel that you can’t take paddocks out as you will be short of grass, paddocks reseeded in the Spring can produce as much if not more grass in the year of reseeding compared to a paddock of old permanent pasture. The aim is to get a reseed back into production in 60 days. Ideally cultivate the sward 7-10 days after spraying the old grass off. The objective must be to minimise the non-productive period. Weather conditions in spring are generally more stable and predictable than in autumn.
Choosing which field to reseed
Base your decisions on regular farm walks and assessment of recent grass performance. Look out for fields not responding well to nitrogen or producing lower-quality silage and with a longer rotation time. High levels of weeds or unproductive grasses could also indicate it’s time for a reseed. When the field is chosen take soil samples from the area to be reseeded. One sample should be taken from every 5-ha. The samples should representative of the entire field/paddock. Soil tests are crucial to establish the levels of Lime, Phosphorous and Potassium needed.
The next decision is to plough or using min-till. The decision will depend on a number of factors including cost, stoniness of ground, equipment available etc.
Ploughing, although the most expensive option, is a reliable method of reseeding. Ploughing buries pests, thrash and native competitors. It also provides the basis for a sound seedbed. After sowing the field should be rolled to ensure good soil to seed contact and preserve the moisture in the soil.
Min-til cultivation techniques allow perennial ryegrass to be introduced into swards without ploughing. Soil disturbance is minimised so the more fertile soil remains at ground level for use by the young seedlings. Again the seedbed should be rolled after sowing to ensure good seed to soil contact. It is a fast and simplistic method of reseeding. It is important that the sward is grazed tightly if Min-til techniques are to be used as surface trash will not be buried.
All the methods can give excellent results but the basic requirement does not change which is a fine firm seedbed. This will conserve moisture, necessary for germination. After sowing, the seedbed should be rolled to “press-in” the seeds and ensure good seed-soil contact.
Reseeding provides the opportunity to select grass varieties which suit your soil type and production system and allows you to use the latest advances in grassland genetics. When selecting varieties for a reseed, refer to the 2021 Pasture Profit Index. Varieties in the index are proven under Irish conditions and give you access to the very latest genetics. Rhyno Farm store has a wide range of grass seed from DLF seeds and Germinal seeds in stock. We have grass seed suitable for cutting and grazing, silage, heavy ground and overseeding. We can cater for special mixes or specific varieties on request. A farm visit for a field/paddock assessment can be arranged at no extra cost. For more information on the grass seed mixes or for brochures call Rhyno Mills or your local sales representative.
Dr Brendan O’Neill B.Agr.Sc, Ph.D
Ruminant Nutritionist
Rhyno Mills, Feed & Farm Store