Certain grass weeds are becoming a very big problem for UK farmers in arable rotations. This is due to a combination of reasons which is providing the ‘perfect storm’ for their proliferation.
Most farmers are experiencing this to some degree, although certain farming systems and soil types create the correct conditions for grass weeds to multiply.
The most common species to cause problems for the arable farmer are black grass, bromes, ryegrass and wild oats. The problem is getting worse and so I am going to discuss the probable reasons for this and what we are doing about it on our farm.
Reasons For Grass Weed Proliferation
On many farms the rotation hasn’t changed for a number of years, but the problem has got much worse over the past few years. So what has changed?
Certain key herbicides have had their licences revoked. This has led to a reliance on fewer herbicides which may not be as effective or this may lead to resistance and so worse control. Resistance to Atlantis is certainly evident, which used to give good post emergence control of blackgrass in wheat.
There has been a trend towards non-inversion tillage by farmers in an effort to cut crop establishment costs. This can bring certain benefits to the soil, but does usually result in a greater number of grass weed seeds germinating and growing in the crop.
We have seen some wetter weather over recent years and many farm drainage systems have come to the end of their lives creating wetter soils which create conditions conducive to grass weed growth.
Situation On Our Farm
Approximatey 60 percent of our farm is of a medium to heavy soil type which we farm with autumn sown crops. The reason for this is that crop establishment and yields are more consistent than spring cropping on this type of land.
However, we aren’t too bad for grass weeds. We have one particularly bad patch of black grass that is about the size of a tennis court. For the past 4 or 5 years we have worked at erradicating this patch. The black grass population has reduced in this patch, but we haven’t got rid of it as yet. We have sprayed tank mixes of pre-emergence herbicides in the autumn with reasonable effect, but far from total control. We have used Atalantis, but this is becoming less effective. We have sprayed remaining plants off with glyphosate in the crop just as the seed heads have formed. We have hand rogued any remaining plants on the outer edges of the patch. This strategy is working, but we are still not rid of this patch and it looks like it may take a few years yet to erradicate it altogether.
When beans or oilseed rape are grown in the field there are some different herbicides available, but we are finding that they are not as effective as they once were. We pay close attention to the correct water volumes, nozzle choice and weather conditions when applying agrochemicals so they are applied in the most effective way.
The rest of the farm is relatively free of black grass, although it is in low populations across all the winter cropping soils. I walk every field each year and hand rogue any plants. This is hard and tedious work. In a typical 15 acre field I would expect to pull about 20 plants that the herbicides haven’t contolled. I think this is time well spent, as the populations can quickly increase and we could soon get into the situation like we did with the small tennis court sized patch.
If I see a black grass plant in the crop when I am travelling through with the crop sprayer I stop, get out of the tractor and pull the offending plant and remove it from the field. When ever I pull a blackgrass plant I carry it off the field just in case any of the seeds have set.
Why Black Grass
You will notice that I have been talking about black grass, and haven’t really touched on the bromes, ryegrass, wild oats, annual meadow grass or any others. These are all problematic weeds to the arable farmers, but black grass is potentially by far the worst.
Black grass plants are extremely prolific in their seed setting and shedding, typically shedding 1000 – 2000 seeds per plant. The seeds are also usually shed before harvest, so no seeds are removed by the harvesting procedure. This is not the case for wild oats or brome, where a certain proportion of the seed is harvested by the combine and removed from the field and many less seeds are produced per plant.
The heavier the soil type the more moisture retentive it tends to be, which is not only the best conditions for grass weeds to grow, but also the least conducive to spring cropping (spring cropping can be good for black grass reduction as the weed doesn’t tend to germinate in spring. Heavier soils are also more difficult to create a fine seed bed, this can lead to a lower germination rate of the crop and hence less crop competion against the weeds. Any large clods can weather down with rain and then weed seeds can germinate with no chemical layer in place to kill them.
As our farm is currently 250 acres it is possible for me to walk the crops and rogue the few plants that are there. Obviously this isn’t so easy on much larger farms, as there is only a few weeks to walk the crops and remove the weeds. As soon as the populations start to get too high then hand weeding isn’t an option anyway.
One future control measure that some larger farms may be able to employ is precision mapping of the weed patches via GPS. Once identified it would be possible to adjust herbicide concentrations in these areas, patch spray glyphosate and patch cultivate to reduce the populations.
These are weeds which start in patches before spreading across the field, so precision farming methods would work well. Systems are already in development to identify and map the weeds.
We hope to eradicate the single patch of black grass within the next few years by continually working on it. This season the wheat in that field was sprayed pre-emergence, but we still had a few plants. We decided not to spray with Atlantis, as we thought we could pull them by hand and didn’t want to add to the resistance problem. There were approximately 100 plants when I pulled them in mid May. I will keep going back to see if any more plants become visible through late may and June.
It will be an ongoing practice to hand rogue all the fields.
We will continue to use a plough based cultivation stategy in most situations. We believe there may be a place for some non-inversion crop establishment as an aid to keeping burried seeds down for an extra season. Normally this would be when oilseed rape is established.
Non-inversion establishment on our soils later in the autumn have given variable results so we don’t see it as been useful on our farm for the wheat or barley drilling. It can give better seed to soil contact than ploughing and retain moisture and germination rate in a dry time, but it has also tended to increase the chances of winter waterlogging compared to ploughing.
We have grown spring beans for the past two seasons which will help with control. We have also introduced grass silage leys into the arabe rotation. Any grass weeds are mown and harvested in the silage before they seed.
Ourselves and other farmers need to be aware of the spread of grass weeds from farm to farm through combine harvesters. There is a tendancy for farmers to rely more on contractors or to share combine harvesters, so this is a path for spreading the weed seeds. We own our own combine, but we do do some contracting work with it. If we were to go to another farm that had a grass weed problem we would cut the problem areas first and then finish off in the cleaner part of the crop so that the inside of the combine would be relatively clean before returning back to our farm. We would refuse any contracting work in fields with bad black grass populations. We are also cautious to not import any manures as we would not know if the bedding straw had been full of grass weed seeds.
These all seem like quite fastidious management decisions, but we believe they are worthwhile. There are few, if any, new herbicides currently in development and we could loose some more of the actives that we have available. Therefore, the situation could get more difficult.
Ammonium Nitrate fertiliser prices have stayed firm at £390/tonne through December of 2008. It is not surprising to hear that fertiliser traders and manufacturers are advising farmers to continue buying to secure supplies – well of course it’s not surprising, they are trying to sell as much product as possible before the price crashes!
Ian Moseley (fertiliser manager for Wynnstay) was quoted in the Farmer’s Weekly as saying “Although the price of urea has collapsed, ammonium nitrate has stayed firm at £390/tonne for December.” And saying of urea prices “It’s dependent on the Asian markey, which usually starts buying in January”. He warned that if farmers delayed purchases, there was a danger that farmers could be left waiting for deliveries in spring, and talking of delivery said “If this suddenly gets pushed into February, then there won’t be enough stock or sufficient transport facilities to meet demand”.
Well it is the view of Farmingfriends that any fertiliser manufacturer or trader should take a beginners course in economics – simple supply and demand economics suggest that fertiliser manufacturers will have been producing product to maximum capacity to try and capitalise on the grain price 5 months ago. Now that the global grain price has fallen to less than half what it was at its peak, then demand for fertiliser will also fall. The fall in demand will be compounded by the fall in oil price, meaning that oilseeds will be in lower demand for biodiesel production (reducing fertiliser demand).
Farmers will look to reduce fertiliser application rates in the spring, possibly by as much as 25%. We all know that ammonium nitrate doesn’t store well from one seaon to the next, so if manufacturers do not move product in spring 2009, they will be left with deteriorating stock.
So the prediction is that prices will fall for AN as they have done with urea due to falling demand, falling oil prices (reducing production costs and demand) and stockpiles of product at plants, docks and distribution warehouses.
The supply industry has been feeding the media, scaring farmers into making purchases at inflated prices since early summer, which can only be described as underhand – as they must have seen the price falls coming. On this farm we predicted what was happening and have not bought any fertiliser yet for 2009. It is clear that any farmers who haven’t yet purchased will be holding out for an avalanche of price falls. We expect ammonium nitrate prices to fall below £200/t and comparing historic nitrogen and grain prices we could even see nitrogen sub £130.
The potato harvest has begun for our farm this week and so I am now grading potatoes. This means that once the potatoes are lifted from the field, they are then tipped from the trailer onto a conveyor belt that allows us to grade the potatoes by picking out the following items;
Although grading potatoes can be a little bit monotonous for some people, the conversation at our grader is certainly entertaining. I suggested that I tape the conversations and include them on my website as a podcast or should I say “potato-cast”!!!
An arable crop is a plant (cereal, fruit or vegetable) that is cultivated for food or other uses, on ploughed land.
How many arable crops can you name? Can you name 30 or more?
Have a go at naming arable crops in the contact form below and the reader who names the most will win a prize. As contestants enter I will let you know the score to beat. You may enter more than once if you wish! Enter by filling in your name, email address and listing all the arable crops you can name. Good Luck. Score to beat is…….33.
We were able to harvest some more of the oilseed rape on Wednesday but we still haven’t finished as the remaining areas are still too wet for the combine to travel. The combine repeatedly got stuck but we were able to ‘dig it out’ with a spade and by jolting it backwards and forwards we would get the machine out and have an attempt in another area of the field. Steady progress continued until 7.30pm when we got stuck once more. I gave the engine full throttle and tried to reverse out of the mud to the sound of a huge crack and the combine slumped over to the left. I immediately knew what had happened -the axle/reduction gearbox hub had snapped and the wheel had fallen off and was now trapped under the frame of the combine.
Having only harvested 5 acres since the last disaster with the unloading spout we were now broken down again – and in glorious harvesting weather. We’d all had enough that night and called it a day. I went spraying potatoes at 6.30 on Thursday morning and then loaded the Land Rover up with blocks of wood and hydraulic jacks ready to try and repair the wheel hub. Luckily we found a second hand hub about 30 miles away which we had to remove from a fire damaged combine before returning home with it. We had to place the wooden blocks under the front axle and then dig out the soil from under the wheel to relieve the weight of the combine that was resting on the wheel. The wheel came out relatively easily and so the next job was to jack the combine up so that the new hub and the wheel could be refitted. The wooden blocks were continually sinking into the soil because the machine had got stuck in a ‘wet hole’ in the field. After several attempts of jacking and then chocking we were able to get the combine to a height at which the wheel could be refitted. The wheel and the hub are both very heavy so we needed to use the forklift which was also sinking in the wet soil.
Harvest recommenced at 4pm after another hard day’s work of repairs. The forklift, wooden blocks, tools, chains, straps and the old wheel hub were abandoned there in the field while we moved onto the next (hopefully drier) field. The combine was altered to harvest wheat and we got started about 5pm and by 8pm the 8 acre field was completed. The grain was 14.7% moisture which is dry enough to put into the grain store without having to dry it down any further. Hopefully the wheat harvest will continue on Friday and we keep our fingers crossed that there are no more mechanical problems.
Harvest on the farm is now progressing rapidly after a slow start. The initial problems have been travelling with the combine, which has been sinking in the saturated soil. The solution to this problem has been to source a set of flotation ‘terra’ tyres and fit them to the combine. Terra tyres have been trading at a premium over recent weeks and long waiting lists have been quoted for new wheel assemblies. Luckily we knew of a neighbour who had a set that they weren’t using so all we had to do was get some wheel centres manufactured by a local engineering firm (£160 for the pair on Saturday morning) and we could get the wheels onto the combine. The other choice would have been to add dual wheels to the existing standard combine wheels, however this can put excess stress on the hubs and is more likely to result in a broken wheel hub/axle. The new tyres have proved useful as the combine has been able to travel along the heavy land fields, although they are still not providing sufficient carrying capacity on the saturated sand land.
Tomorrow will see the last couple of acres of winter barley finished, but we still have 16 acres of oilseed rape left to harvest. The early drilled wheat is ‘fit’ and so tomorrow we will decide whether to try the rape again or go to the wheat. The rape is most at risk of been lost to shedding as it has been ripe for sometime now, whereas the wheat is only just ready for harvesting and so would not come to any harm for a week or so.
Silage fields are now dry enough to cut, but the mower is currently having bearings replaced which were damaged by the floods. Hopefully the mower will be ready by the time we have a window inbetween cereals harvest to make the silage.
On a slightly more embarrassing note, what I have failed to mention in this harvest report is what we have been busy doing this morning. Last night at about 6pm I was driving the combine when I did the thing that all combine drivers fear most - I hit a tree with the unloading spout (the bit that sticks out of the side of the combine to transfer grain into the trailers). It was the last strip of the field along a hedge side and I was concentrating on the pool of water/wet hole and the likelihood of bogging down, but unfortunately this had distracted my concentration away from the fact that the spout was in the out position and that I was going the wrong way round the field. There was a huge bang and the emptying auger shaft was bent and the tube was broken back in one place and dented in several others, just when the sun was shinning and the newly aquired terra tyres were doing their bit. The quote for a new one was in excess of £3,000, and although we are technically insured we decided to try and repair the damage, as after the recent floods we thought the insurance company may not be too receptive to our latest accident! After some inventive engineering, grinding, bashing and welding by my brother until late on Monday night and then again on Tuesday morning, the repair was successful and we were back to the field by 2.30pm. Needless to say that news of this sort spreads rapidly around the neighbours and we had several visitors today to see how the repair was going (or more likely they came to wind me up!)
My day started at 6.30am with spraying potatoes to protect against blight, helping repair the combine spout and then at 3.30pm I started round baling 29 acres of straw which I got finished at about 8.20pm. One of the belt joiners on the baler has started to rip and so that must now be repaired.