Project Lamport leads fight against resistant


blackgrass • Cover crops and spring drilling help • Glyphosate remains key control tool • Winter cropping can cause problems


S


pring drilling on heavy land can help control blackgrass – but reverting to winter cropping too soon can quickly undo the good work, according to the latest trial results from Agrovista. An early autumn-sown cover crop based on black oats, followed by spring wheat, has achieved the best blackgrass control for the past four seasons at Agrovista’s Project Lamport site in North- amptonshire.


Untreated populations of re-


sistant blackgrass at the site can reach 2000 plants/m2. The cover crop is combi-drilled after a light discing. This, together with the slow early growth of black oats, encourages blackgrass to chit and establish well.


The cover crop then bulks up, conditioning and draining the


No spring flush


“The key is to move the soil to maximise blackgrass germina- tion when we establish the cov- er crop, but to minimise soil move- ment in spring when establishing the wheat crop to minimise the chances of a spring flush.” Spring wheat KWS Willow,


was sown at 500 seeds/m2 on 28 March with a Great Plains Saxon direct drill to keep soil movement to a minimum. But using discs only on a Vaderstad drill or simi- lar can produce a similar low-dis- turbance performance, says Mr Woodhead.


“Seed rate is key – we only ex-


pect 40-60% germination in this land, and crop competition is im- portant – blackgrass will quickly fill any gaps.”


Attention to detail is key when


Cover crops are destroyed at Christmas, rather than a fortnight before drilling, says Steward Woodhead


drilling – the operator must be on board with the process, says Mr Woodhead. “You need to check tractor tyre pressure and travel at the appropriate speed and di-


heavy soil over winter. Both it and the blackgrass are then de- stroyed with two sequential ap- plications of glyphosate before drilling.


This has allowed allows a prof- itable spring cereal to be estab- lished on potentially difficult clay soils over a series of very differ- ent seasons, while driving down blackgrass numbers in crops and reducing the soil seed bank, says Agrovista technical manag- er Stewart Woodhead.


The best control has been achieved using a black oat-based cover crop in tandem with direct-drilled spring wheat


rection to reduce unnecessary soil movement.”


Optimum timing Destroying the cover crop with glyphosate around Christmas, rather than a couple of weeks before drilling, appears to be the optimum timing in year two on- wards. This avoids leaving excess debris that traps too much mois- ture in the top couple of centime- tres of soil.


Under this regime yields hit 8.65t/ha last season, while profits neared £1000/ha, allowing for the cost of cover crop seed and with wheat priced at £135/t. The black- grass count was reduced to just 1.4 plants/m2. Mr Woodhead ex- pects a similar performance this season.


By contrast, the standard farm practice plot – two winter wheats followed by oilseed rape – of first wheat, combi-drilled at the end of September, was inundated with blackgrass, despite a full herbicide programme costing


around £150/ha. “Four years after using the


plough and throwing the best chemistry we have at it, the plot still contains about 500 heads/ m2,” says Mr Woodhead. This wheat would yield in the region of 5-7t/ha, which would lose money.


No quick fix


Reverting to winter cropping too quickly can lead to big problems, especially on a high blackgrass site such as Lamport, Mr Wood- head warns.


In autumn 2015, one plot was


put back into winter wheat af- ter two years of overwintered cov- er crop/spring wheat. “This was a massive mistake – we got an enormous chit of blackgrass.” The cover crop/spring wheat sequence was re-introduced this season but was sprayed off due to blackgrass pressure. “We have lost two seasons of profitable crop- ping and will have to reset the blackgrass control clock,” says Mr Woodhead.


OCTOBER 2017 • MIDLAND FARMER 13


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40