Last week saw the start of the silage season beginning on many farms across the country and many farmers are hoping to produce high-quality silage.
Although grass growth has been poor so far this year, many farmers made the decision to cut early and hope for growth to come in the coming days and weeks.
Many farmers are now reportedly planning on operating a three-cut system for 2021, rather than the usual two-cut system.
Monitor swards
For farmers who have not cut yet, they should be going out and examining their closed paddocks to see what growth stage they are at – to determine whether or not they are fit for harvest.
The quality or the dry matter digestibility (DMD) of the silage will depend on how much leaf and how little stem, seed heads and dead herbage are present in the sward when it is harvested.
However, poorly preserved silage can cause a reduction in silage quality, even if grass quality was good at harvest.
Harvest date May 1 May 8 May 15 May 22 May 29 June 5 June 12 June 19 June 26 July 3 Yield (t DM/ha) 2.92 3.99 4.98 5.96 6.79 7.82 8.48 8.93 9.50 9.83 DMD% 79.9 77.9 77.5 76.6 74.6 69.2 67.9 64.3 63.5 58.2
Harvest date for high-quality silage
The target should be to harvest first-cut silage before the end of the first week in June.
The heading date of the ryegrass also has a role to play in determining the cutting date of the sward; you should be aiming to cut before the seed head begins to emerge on the grass plant.
Intermediate-heading varieties will begin heading out in the second half of May and late-heading varieties in the first half of June.
Nitrogen
Farmers commonly delay cutting because they are waiting for the nitrogen (N) that they have spread, to be used up.
When trying to determine if the N has been used up by the grass plant or not, Teagasc recommends going by the rule of thumb – ‘silage uses 2.5kg (two units) of N a day’.
Although, the crop can be cut earlier if weather conditions are dry and sugar levels are good (above 3%).
However, Teagasc also recommends “to test a sample rather than wait for the N to be used up”.