WHEN should grass be
cut for silage this very
dry spring? Cutting early rather than leav-ing swards standing for longer is worth considering where no real rainfall appears likely.
So says Ecosyl NI silage specialist Ken Stroud of Volac. “Really there are two options,” says Ken, “leave grass in the hope that it will bulk up, or cut it early.
“If you leave it and conditions remain dry there is a risk that both quantity and quality will suffer as the grass starts to dry out and die back.
“Should swards become stressed due to drought there is also a risk it will start to produce seed heads prematurely, which also compromises quality, and turn white at the base. This impacts on its ability to regrow.
“Alternatively, by cutting silage fields early you could still harvest a reasonable crop and have your first cut safely banked. By leaving green stubbles, it should also be easier for it to regrow.
“But be careful; it may wilt faster than you think. With a lack of rain, the grass may already be at around 20 per cent dry matter (DM) stood in the field. So if you mow in the morning and ted it within an hour, it might hit a target of 30 per cent DM that same afternoon and be ready to lift that evening.
“The other thing to consider is if you leave cutting a fortnight and this week’s rain settles in, you may not be able to get back in the field to cut it before the end of May!
“But whenever you cut, remember the potential for unused nitrogen to be present in the crop, which will buffer the fermentation. Grass should contain less than one part per 1,000 of nitrate before cutting. To boost the fermentation, wilt to a dry matter at the top of the normal range of 28-32 per cent DM and use a proven Ecosyl additive.”
Ultimately the Volac additive specialist says cutting decisions should be made on a field-by-field basis. Hence it may be a case of cut some fields and leave some.
Other critical considerations include checking if slurry has been properly washed in before cutting.
Where rain has arrived, watch out for luxury uptake of unused nitrogen fertiliser into the crop before cutting, which could otherwise buffer the fermentat-ion.