Mid-season grassland management is always a challenge – grass is in the reproductive phase, which means it will do everything it can to produce a seed. While good news from a species survival point of view, it’s bad news for farmers, as a seed head needs a stem to support it and a stem is bad for grass quality, milk yield and protein percent.
A typical 21-day rotation length will normally avoid seed head emergence, but when grass is stressed, either due to a lack of moisture or a lack of nutrients, it normally goes to seed much earlier and at a much lower cover.
With many parts of the country now on the precipice of a soil moisture deficit and with much less nitrogen applied this year compared to normal, farmers are reporting a lot of stressed pastures.
Grass growth rates are falling rapidly on many farms as soil moisture deficits begin to bite. The south Munster region appears to be the hardest hit so far.
It looks like rainfall in June will be well below the long-term average of 81mm at Cork Airport
Rainfall levels at Cork Airport are well below the long-term average. Between January and June 2022, total rainfall was 313mm, which is 65% of the long-term average of 485mm. The last six months of 2021 were also much drier than normal, with rainfall at Cork Airport between July and the end of December back 20% on the long-term average.
Rainfall so far for the month of June has been 26mm and with no rain in the long-term forecast, it looks like rainfall in June will be well below the long-term average of 81mm at Cork Airport. While 26mm of rain over the last two weeks is substantial, farmers are saying that it was rendered useless due to the sharp easterly winds that were blowing across the country last week.
Worrying about a drought is futile, as there is every chance that the weather will change before soil moisture deficits really begin to bite. However, it makes sense to plan for a period of lower than normal growth rates over the coming weeks, particularly on farms that are prone to drought or in parts of the country that are getting less than normal rainfall.
The following is some advice for managing grass during the mid-season;
The trigger for additional feed is when average farm cover gets close to going under 500kg/ha and when pre-grazing yields get below 1,000kg/ha and a 21 day rotation length cannot be supported. In a drought situation, all available grass should be eaten, meaning farms can go below 500kg/ha of average farm cover.
However, pre-mowing stemmy swards means the cows have to eat the stem, as they can’t select the nice grass and leave the stemmy grass. Only skip paddocks for silage if there is a true surplus, e.g average farm cover greater than 200kg/cow with growth higher than demand.