Grass growth: Making building covers a piece of cake

Grass is still growing very well across the country, leaving farmers in a good position for building covers – to set themselves up for the final leg of the grazing season.

In terms of average grass growth rates, PastureBase Ireland figures are showing 59kg DM/ha in Ulster, 64kg DM/ha in Leinster, 57kg DM/ha in Connacht and 64kg DM/ha in Munster.

While grass is growing well, grazing conditions have become challenging in some parts of the country due to the high covers and almost persistent rain over the last couple of weeks.

This has meant reaching target residuals – of between 4 and 4.5cm – is becoming a bit of a challenge.

In such cases, it may be time to reintroduce the strip wire and revert to some spring grazing techniques in order to continue achieving maximum grass utilisation and to avoid carrying any dead material over the winter period.

Furthermore, on some farms – particularly lower stocked farms – they are ahead of target in terms of autumn-grazing targets.

Targets for the end of August, according to Teagasc:
  • 2.5 cows/ha – 750kg DM/ha;
  • 3.0 cows/ha – 990kg DM/ha;
  • 3.5 cows/ha – 980kg DM/ha.

It is important for farmers in this scenario to act promptly and identify paddocks which can be taken out for silage, while growth rates are still high. Supplementation should also be reduced in such instances.

Measuring grass weekly will help you know how much grass you have and how much grass you need to have.

Fertiliser deadline

The prohibited application period for chemical fertiliser starts on September 15; which is fast approaching.

It is important that farmers continue to spread fertiliser to maximise grass growth. Research completed by Teagasc shows that spreading now – in the month of August – will give a better response than spreading in September.

The average response to every 1kg of nitrogen (N) applied – during early August, early September and early October – is shown in the graph below. Approximately 30kg of N/ha (24 units of N/ac) was applied to test response levels.

The grass growth response to the N application in early August was 27kg of DM/kg of N. In September, 19kg of DM/kg of N was achieved.

Naturally, the lowest response was in October, when a growth response of 10kg of DM/kg of N was recorded.

From the above figures, farmers can grow almost 1.5 times more grass when N is spread in August rather than September.