There is no doubting the potential reseeded swards can deliver in terms of growing higher volumes of grass, sustaining elevated levels of animal performance and providing an opportunity to make better quality winter forage. Reseeding represents a significant cost, ranging anywhere from €250/acre to €330/acre on average (depending on the method used) but these costs can be quickly covered if the benefits mentioned above are capitalised on. This can only be achieved by putting plans in place that ensure the success of the reseed.

The first question you need to ask yourself is will the farm benefit from the reseed. To explain further, reseeded swards perform best when managed for high output. If the farm’s stocking rate is low and the additional grass grown will not be utilised or the reseed will not be managed in a manner that enhances its longevity, then you may need to reconsider your options. For some drystock farmers operating at low stocking rates, rectifying soil fertility issues may deliver a sufficient boost in grass growth and may satisfy your needs.

Soil fertility should also be high on the agenda where the decision has been made to progress with the reseeding job. Reseeded swards will not perform anywhere close to their full potential if soil fertility is limiting. The longevity of the sward will also be significantly shortened, with perennial ryegrass gradually disappearing from the sward. Sward establishment will also suffer where fertility is inadequate with new seedlings poor to establish if soil pH and phosphorus levels are inadequate. The first step in addressing these issues is getting up-to-date soil analysis. Where soil fertility is very poor then this should possibly be the first port of call.

Land reclamation

Many sheep farmers are located on marginal lands that could also benefit from addressing land drainage issues. This should be carried out well in advance of reseeding, particularly if drains need cleaning or land needs to be shored. Where boundary drains are blocked and there are wet areas in the field, time should be left after draining to see if existing shores that may be present start running. This is often the case and it can save significant expense to give time to test an existing drains network.

The other topic that should be considered is how best to manage the reseed to get the most out of it. Are access and fencing good enough to allow the area to be rotationally grazed or split if required? Sheep fencing remains a popular item of grant aid under the Targeted Agriculture Modernisation Scheme II (TAMS II). The current tranche closes on 7 April but if an application is already made and the reseed is occurring early in the year then at this stage fencing will need to be completed after the reseed as approval takes at least a few months.

Variety selection

The Department of Agriculture have one of the most comprehensive evaluation systems for testing the performance of different varieties of grass and clover seed coming on to the market. This, combined with Teagasc’s Pasture Profit Index (PPI), provides farmers with extensive information to select a grass variety or seed mix that best suits their system. The index is calculated on several factors which are weighted on their importance as follows – persistency (34.3%), quality (20.3%), spring DM yield (15.4%), silage quality (15%), autumn DM yield (9.3%) and mid-season DM yield (5.7%). The full Department recommended list can be found at www.agriculture.gov.ie.

For seed mixtures aimed at grazing and possibly silage/hay production, the advice is to select a mixture of diploid and tetraploid varieties. Tetraploid varieties are described as being of a higher quality than diploids and are more drought resistant. They have a lower tiller density, however, and this can lead to open swards which can affect persistency in wetter soils.

Diploids have a better tillering capacity and also have a higher dry matter, with the general recommendation to use a 70:30 mix of diploids and tetraploids in swards for general purpose use. In sheep systems where the focus is on grazing early in the year, varieties with intermediate to late heading will also be easier to manage. Varieties selected should be fairly uniform on heading date for ease of management. When looking at the PPI, predicted production in a sheep context should be fairly well balanced over the season.

While perennial ryegrass is the dominant grass variety selected for use on farms, there are instances where it is more advisable to select varieties that may have lower performance but are more suitable to different land types or systems.

For example, in peat soils, selecting more traditional grass varieties may be a better option while for organic farming enterprises some farmers are also finding grass varieties with deeper roots or a mixture of alternative forages work best for them.

Clover content

The final consideration is incorporating clover into the seed mix. Where possible, clover should be incorporated as it will deliver gains in animal performance, especially later in the year. The most suitable varieties for grazing with sheep are small-leaf varieties as large-leaf varieties will find it difficult to compete with the dense nature of sheep swards. In a mixed grazing system, it is best to use a mixture of small- and medium-size leaf varieties. If weeds such as docks were an issue in the sward before reseeding, it may be best to delay and incorporate clover at a later date as many of the best-performing herbicides for controlling docks post-emergence are not clover safe.