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10 Sep 2020

5x5 farmers boost black-grass control

As featured in Arable Farming Magazine

5x5 farmers boost black-grass control

by Arable Farming September 2020

Shallow cultivation and low disturbance drilling have been essential for controlling black-grass in the 5x5 project. With the project now in its final year, Arable Farming finds out what the farmers have achieved.


For Cambridgeshire farm manager Paul Drinkwater, the 5x5 project field is in a better situation now than it was at the onset of the project.

He says: Over the course of the project I would say we have done what we wanted proved we can have a profitable

rotation which also stops blackgrass getting out of hand on this soil regardless of weather and other problems.

Mr Drinkwater, who is retiring this summer, has put in place a black-grass control system for his successor to continue.

The plan for this land in future is to do as little ploughing and deep cultivation as possible to keep black-grass in the

surface layer. Weve made adjustments to our methods; before we were min-tilling to fivesix inches, now we have gone shallower to 3-4in but getting really shallow as some people recommend is very tricky.


Last autumn, Mr Drinkwater was the only project farmer to sow wheat, all the others were unable to drill as a result of waterlogged soil conditions.

Even so, Mr Drinkwater had to change from the shallow cultivation approach.

We are back in winter wheat for the first time in five years in the 5x5 field. Last autumn we drilled winter wheat on October 28 after sugar beet. The ground had to be ploughed before drilling; it was the only way to establish the crop even though one of our aims was to stop relying on the plough.

We were in the situation of ‘wed better get something in, so we ploughed. The land was last ploughed in 2012, so there has been plenty of time for any buried seed to die off.

The crop received a preem of Liberator in March.

Its had a full herbicide programme to control blackgrass, says Mr Drinkwater.


Norwich farmer James Thomas has always been the exception in the project as he started with much lower levels of black-grass. Like many farmers, he could not drill everything as planned last autumn due to bad weather.

The 5x5 field suffered from a failed oilseed rape crop due to flea beetle and was then sowed with a forage maize for anaerobic digestion in spring, with winter wheat pencilled in for autumn 2020.

Despite growing maize before, Mr Thomas has not drilled it on such heavy land and followed it immediately with wheat.

He says: I hope to harvest at the end of September or early October and then quickly cultivate, spray off and then drill the wheat crop. Obviously, it will depend on the weather.


During the project, black-grass has remained manageable and is still in certain hotspots where we need to keep an eye on it. At the moment, it is there, and we have it under control, but we are not taking any chances.

Bayer/Anglia Farmers 5x5 project

The 5x5 project has followed black-grass control on five farms over five years. Each of the farmers involved chose one field which was monitored closely over the five years, although the grower and his agronomist continued to make all the decisions around cropping and crop protection.

Bayer provided assistance with black-grass headcounts, mapping and resistance testing of black-grass populations.


Although facing a similar set of problems to the other project farmers, Northamptonshire farmer Keith

Thompson will continue with late drilling across the whole area affected by black-grass.

He says: Only 30% of the winter wheat area got drilled as planned. Never before have I not completed

the autumn drilling plan, so it was quite a shock. It will still be in the back of our minds this year, but it

isnt changing the overall plan. There was nothing we couldve done differently to improve the situation.

Having looked at crops on other farms which were drilled in wet conditions, Mr Thompson is confident he

made the correct decision waiting until spring.

It reinforces my view there is no point drilling a crop in bad conditions, its setting it up to fail. You then

spend the rest of the season chasing problems rather than pushing the crop to its potential.

The 5x5 field is in spring wheat this year instead of winter wheat as planned. With an expected yield of five to six tonnes/hectare, Mr Thompson is planning another wheat crop to get productivity back on track. The only upside of the spring crop is that it has provided a good level of black-grass control.


We applied a pre-em of 0.3 litres/ha Liberator + pendimethalin to keep blackgrass under control. As there is relatively little black-grass in the crop and consequently low seed return we will use shallow cultivation and direct drilling.

Soil is in good condition, so any deeper cultivation will be targeted at problem areas. The rain last autumn did create a pan at about 2in, so drilling should be

enough to sort this out. We also use variable rate seed which helps with weed control and maintains yield potential in poorer areas.


Leighton Bromswold farmer Lenny Stamper has successfully controlled blackgrass during the project with

shallower cultivation and late drilling, but last autumn caused problems.

The 5x5 field was intended to be winter wheat, but wet weather prevented drilling. As a result, the field will go into wheat this autumn, however the consequences of last autumn will affect planning.

Mr Stamper says: We only got a small percentage of wheat drilled last year because of the wet weather. We drilled spring beans and spring barley instead, but this year we are intending to drill a large area of wheat.

Harvest 2019 was very good for us, so weve been fine this year despite the difficult autumn. But we need a better year in 2021 to get some cash in the bank, so a good wheat crop is essential. Youve got to be realistic; cashflow is important on-farm to invest in new equipment and buildings.

We will pick cleaner fields for early drilling and land with serious problems will still get drilled later.

The 5x5 focus field is still scheduled for late drilling so Mr Stamper can measure the reduction in black-grass in wheat during the project when using the most effective control methods. But looking ahead he sees challenges to drilling the entire wheat area late.

Oilseed rape

Like many farmers he plans to significantly reduce his oilseed rape area next season, replacing OSR with winter beans, but winter wheat will also fill the gap. As a result, drilling some wheat in late-September/ early October is a necessary step to spread workloads and provide some insurance against another wet autumn.

He says: Last autumn, some wheat finally went in without a pre-em in November. It established poorly and had lots of blackgrass. If a crop is going to carry lots of weeds to harvest it is better to drill it early when it still has good yield potential to compensate for bad areas of black-grass.


The fifth project farmer Julian Swift retired during the course of project.

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