Linseeds best wheat break crop
By Andrew Blake
LINSEED is one of the best break crops for wheat growers – in the south at least, according to latest figures from a group of management consultants.
For the past two seasons wheats after linseed have outyielded crops following a wide range of alternatives for the 25 growers using Optimix field recording systems under the wing of O & N Management Systems.
The company, a joint venture between four members of the Association of Independent Crop Consultants, advises clients on about 18,200ha (45,000 acres) from Kent to the Cotswolds and Leicestershire.
The findings, which suggest winter oats are the least useful break, come from detailed computer analysis of farm results by Cirencester-based Diana Nettleton and her colleagues.
Wheats after linseed in 1996 averaged about 9.7t/ha (3.9t/acre). But those after winter oats gave only 7.2t/ha (2.9t/acre). Of the dozen breaks examined, peas and maize were the next most useful.
Next least valuable after oats, not unexpectedly says Mrs Nettleton, were second wheats followed closely, perhaps more surprisingly, by set-aside.
Kent-based Henry Overman is cautious about the findings. "We need to look much harder at what is going on. Limited data can always skew results."
He believes winter oats poor showing is mainly because official nitrogen recommendations for following wheats have recently been shown to be wrong. MAFF work suggests rates should be much higher, especially where the oat straw is removed, he says. "If you think you have got an index of zero you should probably think of it as minus three."
A key advantage of linseed as a break seems to be the absence of slug damage in following wheats, says Sussex-based Rachel Evans.
OMS 1996 wheat yields according to previous crop (t/ha)
Second w wheat7.9
O & N general husbandry tips
• Winter barley disease key to yields ranging from "disappointing to best ever". Early disease control vital. Net blotch needs watching. Volunteers acting as pest and disease carriers.
• Good results with trials of new seed dressing against BYDV.
• Barley gross margins emphasise importance of achieving quality in malting varieties.
• Winter oilseed rape performance improving, but costs rising due to better understanding of need for fungicides.
• Conditions rather than drilling date key to rape establishment.
• Swathed NIAB trials may miss varietal differences. Cutting a week too early trims 10% off yield.
• Diagnostic tests for eyespot useful. But disease progress and need for treatment depends mainly on weather later in season.
• Big variations in pulse yields. Weed control still a problem in peas. Drilled winter beans doing well on heavy land. Combining in damp avoids pod shatter.
• Brigadier wheat tolerant of wide range of sowing dates. Suggestion that for Consort the earlier the better.
• Vitavax seed dressing anti-flea beetle saviour on spring linseed.
• Farm-saved seed helping contain costs at £30-40/ha.
• Better winter oat varieties responsible for good crop year.