If drilling in mid to late summer he recommends the fast-growing hybrid brassicas Swift or Redstart, which have the potential to provide up to seven tonnes of dry matter per hectare within 10-12 weeks of sowing.
“By growing brassicas in between old grassland and a new reseed you are cleaning the ground very effectively, as there are two opportunities for weed control,” he says. “In some cases there may still be time to do this ahead of an autumn reseed, using the brassica as a short term break crop to fill a late summer forage gap. Alternatively, using Maris Kestrel kale could provide autumn or out-wintering forage, ahead of spring reseeding.”
David says that good results can be achieved by spraying off the old swards with a good quality glyphosate and then direct drilling the brassica crop, with this being particularly useful in upland areas.
“Ploughing may not always be the best option, particularly where slopes or stones are a potential problem,” he adds. “Drilling the seed directly into the old sward also minimises poaching and keeps the stock cleaner.
“If there are any problems in the old sward with weeds such as docks and nettles, I would recommend use of a specific weed killer before burning it off with glyphosate to prevent re-infestation.”
Fertiliser should be applied in line with the results of soil sampling, to ensure brassica crops achieve their full potential.