There will be a mixed response on farms to this week’s rain. Those who have finished harvest will be glad of it to help with stubble cultivations, but growers with crops still to cut will not be as happy.
Oilseed rape drilling is proceeding and the rain is very welcome for germination. There are the usual concerns about drilling rape following an application of sulfonylurea or DFF herbicides in the previous crop.
The agrochemical manufacturers advise cultivations and thorough soil mixing to six inches before rape is drilled but many crops are sown without that. Usually we get away with it, but it has been an extremely dry year, residues are likely to be higher than usual.
The rain also ought to give good conditions for pre-emergence herbicides in rape. Check that the crop seed is adequately covered by soil (15mm depth) before spraying. Also be wary of spraying if heavy rain is expected – chemical washed down around the seed can affect germination.
As usual, slugs are a potential problem as soon as the crop emerges. It is advisable to check crops daily for damage. Alternatively put out test baits using layers mash and examine the traps a couple of days later. The weakness of this method is that you can miss a new generation of slugs that have hatched after you have examined your traps.
We now have excellent conditions for producing stale seed-beds to encourage germination of weed seeds and it is an opportunity not to be missed, particularly where blackgrass and bromes are a problem. So, produce a shallow tilth, press it and spray off the resulting flush of weeds with glyphosate.