Agriculture - Combinable Crops, Grass Seeds, Maize & Fodder Crops, Agri Chemicals

Grass Reseeding

Posted: 22 Dec 2011

As published in the December issue of the IGA Newsletter
By Dave Barry

Grass is the key ingredient in Irish livestock farming and sets us apart from most other countries. The benefits are seen in reduced production costs and in the green and environmentally friendly image of our milk and meat products. The rainfall that so often makes grass utilisation difficult is what allows such a consistent supply of grass from year to year. 2011 was a good year for grass growth and the weather allowed a long grazing season.

Grass reseeding is an important grassland management tool leading to increased productivity of livestock farming. Essentially you are sowing the very best grass varieties that are available and replacing broadleaf weeds, grass weeds and older less productive perennial ryegrass plants. There has been a strong message from research and advisory organisations and the seed trade in the past ten years that reseeding pays and delivers increased stock carrying capacity, reduces costs and increases profitability. Based on reseeding rates in Ireland in the past few years this message is being taken up by farmers. There is however much more potential to exploit this important management tool to continue improving efficiency.

In looking at the reseeding rates in any particular year the most important influence is the weather. A farmer needs a good supply of grass on the farm and suitable soil conditions to carry out the cultivation and seed sowing operation, both requirements are weather dependent. On examining the reseeding rates in Ireland over the last 25 years; the level of reseeding is closely linked to weather conditions in the April to September period.

The area of land reseeded with grass in 2011 was about 5% ahead of the ten year average. There was strong demand for grass seed in spring and the autumn was less busy. Weather conditions throughout the summer were good in most of the country; parts of Leinster became very dry at times during the summer and the North West was very wet in August and September. Grass seed availability was tight particularly in the autumn. The more popular recommended list varieties were especially scarce. Grass seed prices also increased in 2011 due to increased production costs for seed and tightness of supplies.

In 2010 the area reseeded was among the biggest for any previous year with rates at 30% ahead of the 10 year average. In 2008 and 2009 the reseeding rates were 30% behind the average due mainly to very poor weather in the April to September period.

Looking forward to 2012, assuming the weather plays its part; grass reseeding rates should again be ahead of the ten year average. The message on the benefits of reseeding that is being delivered by Teagasc and The Irish Grassland Association is certainly having an increasing impact with farmers. In 2011 there were many open days and demonstrations organised by these two organisations that very graphically demonstrated the benefits. Also, there are many farmers planning expansion in dairy production over the coming years and they are likely to increase their reseeding rates as part of these plans. Grass seed supplies will again be tight in 2012 and prices will be higher. It is good advice to secure grass seed mixtures early in the season if you want to pick from the very best varieties.

Grassland reseeding is one of the best paying investments available to grassland farmers. Grazed grass is the cheapest feed for cows and drystock and grass silage is among the cheapest winter feeds you can produce. Reseeded pastures will produce higher annual yields of grass compared to old swards. Grass digestibility and intake potential will improve. Based on recent research at Teagasc Moorepark the biggest impact on improved profitability from reseeding comes from a substantial increase in spring grass yields and autumn grass yields. In a recent study at Moorepark, pastures with 100% perennial ryegrass produced February growth rates of more than twice those of pastures with 40% perennial ryegrass. The annual improvement in profitability is worth over €200 per hectare for the 100% perennial ryegrass sward versus the 40% perennial ryegrass sward.

Perennial ryegrass dominant swards will use nitrogen more efficiently. Fertiliser prices have increased in 2011 and look set to increase further in 2012; this provides an extra incentive to reseed. Reseeding will increase the tonnes of grass produced and increase the grass utilisation and therefore the stock carrying capacity of the farm. This coupled with the improved return on fertiliser should return the reseeding cost within two years.

The timing of reseeding is hugely influenced by weather conditions and grass supply on farms. Spring reseeding generally leads to more successful establishment and gives better opportunities for post emergence weed control. Generally 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. Generally when you plan on spring reseeding you are more likely to get it done.

Grass varieties are constantly being evaluated in recommended list trials, grassland research centre trials and on farms. There is new information coming 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 is the most valuable source of information on the grass varieties that are available. 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, 23 of these were listed and 76 were rejected. The recommended list trial protocol has been adjusted in 2011 to improve the usefulness of the results. There are now two separate trials for all varieties; there is a simulated grazing trial and a two cut silage trial and this information will be presented in future recommended lists probably from 2014.