Reseeded swards have higher yields, better digestibility and superior growth rates in the autumn and spring.
Research at Moorepark has shown old pasture to yield on average, 3 tonne of Dry Matter (DM) /ha less than perennial ryegrass swards.
In Moorepark, pastures with 100% perennial ryegrass had February growth rates of more than twice those with 40% perennial ryegrass. The annual improvement in profitability is worth over €200 per hectare for the 100% perennial ryegrass sward.
According to Teagasc the main benefits are as follows: * Create more productive swards;
* Improve grass quality — up to four units (up tomid-May);
* Improve the nutrientresponse— (+10kg DM/kg of N)
* Increase animal output — 8pc higher milk output/ha
* Reduce silage requirements due to a longer grazing season
* Increase the farm stocking rate However reseeding is expensive at upwards of €200/ac, so you need to ensure that a successful result. Some key points to bear in mind are:
* Identify fields that haven't performed in recent years (slow spring growth, poor response to fertiliser, etc.)
* Soil sample to identify the fertility status of fields and nutrients required as new seedlings are very susceptible to lack of lime and phosphorus (P).
* Slurry (3,000ga/ac) is sufficient to supply the P and potassium (K) nutrients.
* Combine three to four grasses of differing traits to obtain good seasonal DM production (spring/autumn) and high density.
* In choosing a silage mix, go for a high overall DM production and density.
* Information on recommended varieties is available from the Dept. ofAgriculture (www.agriculture.gov.ie) and Agri-Food Biosciences Institute (AFBI) (www.afbini.gov.uk/reclists) . So check out their websites for lots of useful data on the latest grass seed and clover varieties.
Grass varieties are constantly evaluated at grassland research centre trials and on farms. There is new information becoming available all the time about grass varieties. This influences the choice of varieties for the ideal grass mixture whether for grazing or silage.
The Irish recommended list varieties are evaluated for a minimum of two separate sowings and four harvest years at a range of sites around the country.
Varieties will only be listed if they show sufficient merit in terms of overall yield, seasonal yield, digestibility and ground cover score. Over the past eight years there were 99 varieties evaluated for the first time and 76 were rejected.
Spring reseeding generally leads to more successful establishment and gives better opportunities for post emergence weed control. With spring reseeding there is less impact on the grass available for grazing due to high growth rates on the rest of the farm while the reseeded area is out of production.
Ideally graze once or twice, reseed in April and be back grazing in June. When you plan on spring reseeding you are more likely to get it done. The turnaround time for the pasture to be back in production is faster than in autumn at around 60 days.
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