Blackgrass Blues

By Peter Lundgren, The Farmer

I didn’t think it would be long before the thorny issue of blackgrass raises its head (also see previous posts (JB Diego, Scuffing). Blackgrass* has developed resistance to a range of herbicides that were used to control it. Certainly is difficult to attend a farmers’ meeting or farming show without the subject of blackgrass being discussed with increasing levels of panic and despair. There’s even a song about it with the wonderful descriptive line ‘a five o’clock shadow across the fen’  search for ‘The Blackgrass Blues’ by The Ruffs on YouTube.

This is going to be a lengthy response because, in my opinion, blackgrass in symptomatic of a number of issues in farming today.

In most cases, at the top of the list of considerations for the grower is the issue of finance and the basic need for the grower to feed his/her family, put shoes on the kid’s feet, and convince the bank manager to extend the overdraft for another year! OK, I’m being emotive – but that’s not too far from the truth at this time of low commodity prices. So in response to this financial pressure growers have been forced into cropping and rotation decisions based more on profitability than on best farming practice – and I include myself as one of the guilty ones.

What we have seen over many years is increased specialisation in farming with the demise of mixed farming and mixed farming rotations**. Over the last ten years or so, a reduction in the profitability of crops sown in the spring like sugar beet and pulses (peas and beans) has led to an increase in crops that are sown in winter – especially winter wheat and winter rape. Sowing crops in winter has impacted on the traditional crop rotation by closing the window for controlling weeds using, cultural, mechanical or chemical controls. By sowing crops in Winter, weeds that grow at the same time are exposed to increased applications of a limited number of herbicides which creates a perfect situation for nature to select for herbicide tolerance i.e. the plants we don’t want to grow in our fields develop resistance to the herbicides that are designed to kill them and just keep on growing. This concentration on winter sowing wheat and oilseed rape has led to the emergence of blackgrass that is herbicide tolerant.

Currently there is no new chemistry available that works against blackgrass in the growing cereal or oilseed rape crop and, at the same time, some herbicides have been withdrawn from the market place because of concerns over their impact on human health and/or the environment.

It’s also worth saying at this stage that I’m hearing of populations of blackgrass that are acquiring a degree of tolerance to glyphosate*** and blackgrass gaining tolerance to glyphosate would be a nightmare scenario for farmers. But maybe that’s not surprising when farmers and their advisors are reliant on glyphosate and are using multiple doses of diluted half-rate glyphosate on blackgrass to keep costs down.

The ease with which tolerant blackgrass has spread across the country is also symptomatic. The increase in machine capacity, with single bigger machines working over large areas and numerous farms, has increased the potential to spread the blackgrass seed. The blackgrass came on to my farm from dirty contractor’s machinery. This is not uncommon and in my case it was a contractor’s combine harvester that brought the seeds onto my farm. On my neighbour’s farm a contractor’s baler broke down and as the side panels were removed by the mechanic, blackgrass seeds fell out. And then there are the natural agents of spreading seeds – wind, water and birds – helping blackgrass become very widespread.

And it’s not just blackgrass. I’ve got pansies on the farm that are proving increasingly difficult to control – these are badass pansies! – and there are a number of other arable weeds showing increased tolerance to herbicides.

My own thinking is that control of herbicide tolerant weeds like blackgrass is heralding an inevitable change in conventional farm management and culture. In the past our research organisations and scientists have come to the rescue but as growers recognise that there isn’t a silver bullet to problems like tolerant weeds and pests and they are having to revisit their management and adopt alternative strategies.

A number of these strategies, like crop rotation and integrated pest management, would be recognised by our great grandfathers. This is nothing to be ashamed of. Our great grandfathers were successful farmers within their era and I think we are foolish not to revisit and consider their techniques with a view to adopt them where appropriate. I also think organic farming has a lot to offer conventional farmers in terms of alternative strategies that can be assimilated into conventional farm management.

So in the short term growers are looking at control of blackgrass through a combination of cultural, chemical and mechanical techniques but, looking to the future, growers desperately need a rotation that includes financially viable spring-sown crops – preferably a spring sown protein crop (for example beans and pulses) to counter the increasing reliance on imported soya for our livestock sector and also open-flowering (insect pollinated flowers) to provide a valuable source of food for bees and beneficial insects.

Notes (added by AMC)

*Blackgrass is a native grass-weed that grows up to 80cm high and flower from May to August and produces a large amount of dark coloured seed before the crop is cut. Seed production ranges from just 50 up to 6,000 seeds per plant. It can occur at very high densities competing with the crop and serious reduce yields if not controlled. For more on Blackgrass look on the web for AHDB (Agriculture & Horticulture Development Board) Cereals & Oilseeds and search for Blackgrass and there is lots of information.

**mixed farms have crops and animals and mixed farming rotations can include grass for livestock, root crops, grains and set aside.

***Glyphosate is a non-selective herbicide. It is effective in killing all plant types including grasses, annual and perennial weeds and some woody plants. It can persist in soil for up to 6 months depending on climate and soil conditions. Google Glyphosate for more information including a very recent WHO (World Health Organisation) report that voiced concerns about possible impacts of glyphosate on human health.




Please feel free to read through questions and responses from the Field of Wheat collective members and the Farmer.


Evening Peter. Thanks for all that info…. is this blackgrass the weeds we were seeing when we were over? It sounds as if the crop rotation option is a great option for the longterm… once the appropriate crop is chosen of course…just wondering what the option for the short term might be? (ie for this field, this season)
Many thanks and hope those badass pansies don’t come get you on the next full mooooooon…..

2015-11-21 21:36:22

Peter Lundgren, The Farmer

I don’t think you saw blackgrass weeds when you came to the collective event. There was plenty of broadleaf weeds and some annual meadow grass but not much blackgrass. However there is undoubtedly tolerant blackgrass in the field of wheat but not in sufficient quantity to affect yield …. yet. So we will have to adopt control measures that anticipate a time when blackgrass will be a problem and do our best to delay that time.
We do have some options for blackgrass control this growing season. I started the growing year trying to control blackgrass using mechanical means before cultivation and sowing; during the growing year we will use herbicides that are still reasonably effective to kill or weaken the blackgrass plants in the field; and then next year I will look at changes to the rotation that allow for better control of blackgrass. Hopefully this three pronged strategy will defer the day when blackgrass becomes a barrier to profitable productive farming on this field.

2015-11-27 13:12:42

Peter Allen-Williams

Hi Peter,

I wonder what you think about the possible comparison of Blackgrass resistance with the stories recently on the news of the increasing resistance of diseases that affect humans to antibiotics? Looks like two strands of the same story to me..

2015-11-25 15:33:15

Peter Lundgren, The Farmer

Hi Peter
There’s certainly a similarity here. And there is also news of a superbug found on livestock farms in China that is tolerant of all antibiotics.
Its amazing how quickly plants, insects and bacteria become tolerant to the chemicals and antibiotics used by farmers for control. And its also amazing the ingenious manner in which weeds, insects and bacteria gain tolerance – very often science has to break new ground to understand how tolerance has been achieved – whilst herbicide tolerant blackgrass is bad, a superbug is far, far worse and a major threat to the wellbeing of mankind.
I believe that farming does have to shoulder the responsibility for adopting farming methods that create the situations that promote tolerance and farmers can’t continue to hide behind the wider desire of consumers and politicians for cheap food.

2015-11-27 12:40:29


Hi Peter. Thanks so much for the reply. Looks like I served a swerveball there then and got you distracted from what I really wanted to ask!! Sorry! When we visited we talked about something needing to be done about what must have been the broadleaf weeds then…. what is the situation regarding them now? Thanks so much! 🙂

2015-12-10 21:15:01