NIAB - National Institute of Agricultural Botany

Orson's Oracle

The bleeding edge?

Posted on 27/06/2012 by Jim Orson

Over the last month black-grass control experiments have been assessed and demonstrated. There is no doubt that the Flowering black-grassissue is how to control the weed with herbicides in dry autumns. We are now so dependent on the pre-emergence and early post-emergence herbicides and typically they will not work anywhere near their best when seedbeds are dry.

In addition, in many cases we have the legacy of a high seed return this year. The whole industry really knows what to do about it but many are looking for new and quick solutions. A quick solution would be a new and effective herbicide. We have known for years that this would not be the case. Until quite recently many farmers still firmly believed that the chemical companies were holding something back.

I have had queries about alternative approaches. Weed wiping has been suggested but there are severe practicalities in keeping the wick from touching the crop. Some farmers are suggesting that the industry should be allowed to return to straw burning. I do not think that this will provide all the answer, even if it were allowed (which, I am sure it won’t).

I was a technical adviser to MAFF when the ban was being discussed. There is no doubt that in many circumstances straw burning would provide some advantage and this was one of the arguments which was presented to MAFF. However, public sentiment was totally against burning.

What interests me is the current debate on the impact of direct drilling on black-grass populations. The impact of primary cultivation on black-grass numbers was assessed in the LINK funded series of trials on the greater understanding of the agro-ecology of the weed. Adopting the Simba Solo resulted in the highest black-grass numbers and the plough resulted in the lowest numbers. Direct drilling was somewhere in between.

So direct drilling was by no means the disaster that some had predicted. There could be several reasons for this. One is that much of the freshly shed black-grass seed is lost from the soil surface. A few years ago The Chadacre Agricultural Trust and The Morley Agricultural Foundation funded a PhD on losses of grass weed seeds from the soil surface. Losses were very significant in the autumn and winter but it was difficult to gauge the role of the different factors. There was, for the first time, the suspicion that some black-grass seeds were eaten by predators, possibly birds.

I believe that the proponents of a straw rake to encourage losses of seeds have a case. Pot trials show that black-grass seed germinates and establishes much faster if buried at a depth of 1 cm (0.5 inches) rather than lying on the surface. This may increase overall losses despite burying the seeds away from the soil surface where they are vulnerable to some losses.

In terms of chemical control with soil acting herbicides, one potential advantage of direct drilling is that the seedling and secondary roots of black-grass may be closer to the soil surface when compared to other approaches to primary tillage. Such differences could be of greater importance where there is significant resistance to the herbicides and when conditions are marginal for herbicide activity.

Of course, there is direct drilling and direct drilling. There is a huge difference in the level of soil disturbance between the different types of drill. This has resulted in observations that more black-grass survives between the row of some types of drill and along the row with other types of drill. This aspect could be critical in the longer term. Attention to detail is now the order of the day.

There are, of course, possible downsides to direct drilling. By treating only plants from seed shed in the previous crop, the further development of herbicide resistance will be maximised. This is assuming that resistance can get worse! In addition, there could be some unforeseen circumstances. In Australia, millipedes and earwigs have built up to such high levels in long term direct drilling that they are now damaging crop plants. I am not saying that this would occur on the UK, what I am saying is that there could be problems that we would not have predicted.

However, we will get an early warning because some UK farmers have been direct drilling over the last 10 years or more. Let us hope that they will be on the ‘leading edge’ rather than the ‘bleeding edge’.

If you want to get really depressed, listen to the black-grass blues

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A late winner?

Posted on 18/06/2012 by Jim Orson

The England match against Sweden at the weekend was a cliff-hanger. When Sweden scored their second goal I was moved to walk round the garden. Luckily I was back in front of the screen when England scored their second and third goals.England v Sweden

In many ways the match was a metaphor for wheat growing this year. We had a good establishment and thought we were leading, and then nature struck back. We’ve had pressure from grass-weeds, BYDV and septoria and also face further attacks from fusarium and potential lodging. What a year; at least there’s been no shortage of moisture this spring and early summer! So are we behind or drawing at the moment? More importantly, will we score a late goal to draw or even win?

To score a late goal we need a great grain filling period. This starts at flowering and ends at about 35% moisture content of the grain and during this period it needs to be cool and sunny.

It needs to be cool to extend the grain filling period over as many days a possible. The crop needs, according to varying sources, between 660 to 710 day degrees for grain filling. Day degrees are calculated by dividing the sum of the daily maximum and minimum temperature by two. So if the day’s maximum was 20C and the minimum was 10C, then that day there would have been 15 day degrees - the cooler the weather the longer the grain-fill.

It needs to be sunny to provide the solar radiation to fuel the process of photosynthesis in order to produce carbohydrate i.e. yield. It also helps if the nights are cool to minimise the crop respiring some of the gains made during the day. Crop physiologists’ views vary about how cool; some say below around 9C and others below around 12C. The common features of the good yield years of 1984 and 2008 were sunny cool days and cool nights. We would have had a huge national average yield in 2008 but for the wet harvest that badly delayed combining.

NIAB TAG's Stuart Knight at Cereals EventMuch of the talk at the Cereals Event last week was about wheat yields levelling off. A group of French researchers maintain that in their country this is mainly due to the trend of warmer weather negating the potential gains from variety improvement. Warmer weather has resulted in a reduction in the period of growth from stem extension to ripening and, more specifically in some years, a shorter grain fill period. These conclusions only feed the fire of climate change. However, we’ve seen cooler and warmer weather trends for centuries and so it is important not to jump to conclusions.

There’s no danger that a good UK wheat crop can’t store all the product of a good grain fill. Our varieties in New Zealand can have yields far higher than here. As I said in an earlier blog, this is because we have around the same number of days for grain fill but in New Zealand they have, on average, around 30% more solar radiation during this period. We have a New Zealand farmer staying with us and he attributes his ‘disappointing’ 2012 yields to lack of radiation (and associated very heavy rainfall) during grain fill. ‘Disappointing’ is a relative term. In 2010 he had one field average over 16 t/ha. This would be the world record if he had been minded to adopt the processes necessary to claim it. Interestingly, the variety was Cassius, a UK variety that was not widely grown over here.

So we are in the final part of the match. We need luck to draw or win but we are also carrying some injuries. There’s a lot of black-grass, more septoria on the yield-forming leaves than we would like and there is a nagging doubt about what fusarium may do concerning our ability to push any advantage home. In addition, many crops look a bit ‘wobbly’.

On a personal note, there was one winner from me walking around the garden after Sweden’s second goal. I noticed some slug activity in the bedding plants and treated accordingly. This led to lots of dead slugs on the soil surface on Saturday morning.

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Trust

Posted on 11/06/2012 by Jim Orson

Well, I am back refreshed from a holiday inFrance. The sugar beet and potatoes were not as advanced as would normally be expected, so it seems that they have also suffered from a cold spring.

Whilst I was away there was the mass demonstration against the GM trial at Rothamsted. It seems that ‘mass’ was the wrong description. The organisers said 400 turned up, the police said 200 and a farmer who went along to observe counted no more than 150. Presumably they could not use poor weather as an excuse for such a low turnout.

Do the low numbers suggest a tipping point in the so-called ‘GM debate’? It is hard to tell. Perhaps the self-appointed ‘guardians of our environment’ are not reflecting widespread public concern. Perhaps it also shows that you can cry wolf too often.

The claims that a single small and well regulated trial can despoil the environment have been used too many times. These same arguments were used for the GM crop field-scale evaluations, which were on a far larger area, and the GM potato trial at John Innes, and it’s clear that these have not left any negative legacy.

Last year approximately 160 million hectares of GM crops were grown around the world. As far as anyone knows they, and the GM crops grown over the previous 15 years, have had neither a negative environmental impact nor caused as much as a sneeze in humans. On the contrary, GM crops have led to environmental improvements in some parts of the world by facilitating better soil conservation methods and/or reducing insecticide use. In Canada, GM herbicide tolerance has resulted in canola being a ‘weed cleaning’ crop rather than a ‘dirty’ crop, enabling the widespread adoption of peas (a ‘dirty’ crop) into the rotation and may have resulted in an increase in biodiversity.Rothamsted action day

The general public are becoming aware of these facts and so it is getting progressively harder for those who oppose the technology to scare them. The extra ingredient in the Rothamsted trial was that the scientists did not sit quietly behind their barricades but actively joined the debate. They should be congratulated for doing so.

To achieve public support you have to earn trust and there was an interesting repercussion as a result of the call for mass action. Graham Jellis, speaking on behalf of the British Crop Production Council (BCPC) on Channel 4 News, said that GM crops now accounted 10% of the world crops. This statement obviously caused doubt in some minds, perhaps more so in those unsure of the technology.

Anyway this statement was checked by those who run a website that tries to verify statements made in the media. The site used all the usual tools for verifying this kind of data. Sources ofinformation were discussed, particularly the area of GM crops grown because inevitably it was primarily estimated by those selling GM crops. In addition, there was an interesting debate about what constitutes world cropping. Significantly, there was an acknowledgement that Graham was correct, and he responded by saying that his source ofinformation was the UK Food Standards Agency.

So there may now be a wider acceptance of the success of GM crops and also that the area being adopted is increasing significantly from year to year. This counters the activists’ argument that it is a failed and outdated technology.

I need to stress that I’m not suggesting that GM is ‘the be all and end all’ of agricultural progress, playing a significant role along with other plant breeding techniques. In previous blogs I have expressed caution about the adoption of GM crops without due attention to their possible impact on future cropping options. However, I cannot see how rejecting new forms of agricultural technology will enable us to return to the rural idyll, that some of the objectors seem to crave, without widespread food shortages.

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Bainton opens up a new day out

Posted on 11/06/2012 by Nick Watson

So Thursday 7th June saw the first of three National Agronomy Centre open days. The weather didn't look like it was going to be kind to us, and don't mention the lack of coffee.

With boards up and a field of wheat and oilseed rape the locations for the field tours, Patrick Stephenson, Northern Regional Agronomist, made introductions and welcomed all. With the rain falling senior pathologist Jane Thomas explained the merits of the Optibean programme and Ron Stobart, Head of Communications, discussed the research we are doing in agricultural rotations.

With the rain easing slightly there was the option of going to either field location with Bill Clark, Commercial Technical Director, covering fungicide programmes 'the possibility of a T6 spray' with a look at some crop treated with SDHI fungicides, plus his explanation of the flecking we've seen a lot of this year in wheat crops. Also in the wheat field was Richard Overthrow, Western Regional Agronomist, he was demonstrating the wheat varieties, with several new ones on the list and some highlights to consider for this Autumn.

Over in the Oilseed field, Selwyn Richardson ADAS soil management expert, had dug a suitably large hole to explain the virtues of good soil management, I was surprised to hear that Sugar Beet roots can get as far down as 6ft and OSR as much as 3ft, down deep enough, should it turn dry, to access enough moisture down in the profile to see the plant through the important pod fill period. Alan Dewar talked about insect pest resistance which is becoming more and more of a problem. Finally Simon Kightley, responsible for Oilseeds and Pulses, gave us his enlightening view on the pros and cons of the current OSR varieties along with his choice of the pick of the bunch and ones to look out for in the future.

Also joining us, somewhat drier in the marquee, were representatives from Easton College, HGCA, AFP, RASE, United Oilseeds and CFE.

With the rain abating at 12, the hog roast was a welcome sight and smell, it gave a chance to put down the brollies and chat with a few of the growers attending. Most thought the location was good, with the field display and talks a highlight. It's always good to go to these events, you never know what new bit of information you might pick up, whether on varieties, soil care or the new thinking on why the hell is the cause of that, or just an opportunity to catch up with the rest of the members.

Well one down and two more to go, Morley on the 21st June and Hampshire on the 28th. I'm sure the sun will shine at some point!

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Look before you leap!

Posted on 07/06/2012 by Jim Orson

I have great sympathy with those trying to introduce new crop technologies, which may help us in the challenge to better secure future food supplies.

Take the first halting steps to introduce GM into Europe. Inevitably, the easier to achieve GMs were introduced first; that’s the way with technical developments. GM herbicide tolerant crops offer good and reliable weed control, something for which herbicide manufacturers have been striving over the last few decades.

Not only is weed control in GM herbicide tolerant crops reliable but it offers the real possibility of adopting rational weed control strategies. The grower can check the emerged weed population before application and make an assessment on the risk posedOilseed rape in flower to current and future crops. An application may not be necessary or a lower dose could be used. In most cases, ‘conventional’ herbicide strategies don’t offer this option: weeds have to be controlled before or very soon after they emerge.

However, the potential weed control offered by this technology may be too high in some crops to be acceptable under the EU GM legislation, because it may result in an indirect reduction in the soil weed seedbank. This is deemed a threat to biodiversity in the future. Fancy - a conventional herbicide being banned because it was too effective!

I think that the whole industry is beginning to accept that we need to mitigate the level of weed control now being achieved in the field by encouraging biodiversity on specifically managed areas on the farm. So we could mitigate the impact of the higher levels of weed control possible with GM herbicide tolerant crops. But it is worth pointing out that sympathetically managed herbicide regimes in these GM crops can lead to better within crop biodiversity with no, or very little, threat to the current or future crops.

Part of the anti-GM rhetoric is that the technology is not that special and conventional breeding linked to better knowledge of genomics will result in the same thing. And that’s what has happened with the oilseed rape ‘Clearfield’ varieties tolerant to the imidazilinone herbicides being introduced into Europe.

But now there are campaigners attacking trials containing these varieties complaining that this is GM by the back door! It proves some of those who campaign against GM don’t want any new approaches to food production, but it is also clear that some pine for a return of a rural idyll of small-scale farmers using traditional techniques and cannot see past this point. We may be all right in our rural idyll but outside it more food will have to be produced, possibly with huge environmental implications.

The future is going to get even more complicated. Biotech is opening up other new plant breeding methods and genetic innovation. It is now possible to use GM as part of the process but the final product may not have a GM fingerprint. This is a challenge to regulators if it’s decided that there should be regulations to take into account what is now possible. And in the meantime further new breeding methods will be developed so ‘future proofing’ any new regulations will be a huge challenge.

All novel approaches to crop production need to be considered with care. The ‘imi’ tolerant oilseed rape is a case in point. It offers control of weeds closely related to oilseed rape, namely charlock and runch. It also controls conventional rape volunteers; a very valuable aid to maintaining crop quality. This could be particularly useful in protecting the quality of the high oleic, low linolenic varieties. Of course, this could be the one and only opportunity. The volunteers of ‘imi’ tolerant oilseed rape will be resistant to ALS-inhibitor herbicides.

However, its introduction has to be thought through. The mode of action of the imidazilinone herbicides is ALS inhibition - a very common mode of action with resistance in common poppy, common chickweed and scentless mayweed as well as black-grass. Using an ‘imi’ herbicide in oilseed rape means less reliance on this mode of action elsewhere in the rotation. This will be helped by volunteers on ‘imi’ tolerant oilseed rape being resistant to ALS-inhibitor herbicides.

However, there is one situation that has to be thought through with particular care. Debut, an ALS-inhibitor herbicide, controls oilseed rape volunteers in sugar beet. It enables these two crops to be grown in the same rotation and this may no longer be possible with ‘imi’ tolerant oilseed rape.

 

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