NIAB - National Institute of Agricultural Botany

Orson's Oracle

The promoted narrative

Posted on 17/03/2017 by Jim Orson

A farmer recently mentioned the term ‘the promoted narrative’ over a stimulating lunch. I rather like that because arable agriculture is full of promoted narratives.

A dictionary definition of a narrative is ‘a spoken or written account of connected events; a story’. I think the word ‘story’ summarises some of the statements that I have heard or read in recent weeks.

For instance there is the commonly made statement that an early spring application of chlormequat or another plant growth regulator will stimulate tillering in late sown winter wheat. This is a story. True enough, chlormequat will increase the number of fertile tillers or heads of wheat at harvest. However, it does this by decreasing the tiller loss that occurs from about the first to second node stage rather than by increasing the number of tillers before those growth stages. Hence, application just before the first node stage is perfect for reducing tiller loss. It cannot possibly increase the number of potential tillers when applied in the early spring because only one tiller can emerge from a leaf axil and production of new leaves is a function of thermal time (day degrees) and this process is not modified by plant regulator application.

In terms of yield, the application of chlormequat just before the first node stage of winter wheat can be a good thing in years with a dry spring and a good grain fill. 2011 is a case in point. The wheat crops, untreated by chlormequat, shed too many tillers in May because of the drought. However, the rain in early June and good levels of solar radiation during grain fill meant that there was sufficient photosynthetic activity to feed the extra heads and/or grain sites in the chlormequat treated crops. In the absence of lodging, crop responses of up to 1t/ha were recorded in trials. Sadly the opposite was true in the following year. The dire wet and dull summer of 2012 meant that there was a low natural loss of tillers in May and there was insufficient photosynthesis to fill the grain sites of the untreated crops. Therefore the additional heads and/or grain sites that occurred as a result of chlormequat application were an additional burden. In the absence of lodging, losses from chlormequat application in that year approached the gains measured in 2011.

The early spring application of chlormequat and other plant growth regulators is also said to increase the rooting of late sown wheats. It may do, but independent trials have shown that any yield increase in late sown wheat from this timing is less than that from an application just before the first node stage. Come to think of it, has anyone found that late sown wheats are short of roots in the early spring? Wheat root production increases at an exponential rate during stem extension and so logically, an application of chlormequat just before this stage would be more appropriate. However, I think that any impact on roots from growth regulators is by the bye. I realise that this is a battleground between competing plant growth regulator products but it has never been identified in the field that plant growth regulators can increase nutrient and water capture from the soil.

Another promoted narrative regarding the spring management of late sown wheats is that they need more early nitrogen. They certainly need early nitrogen but they do not need more than a typical conventional crop. This is because the plants are small and while the root system is adequate it is not as developed as a typical conventional crop at this time and so, if anything, applying less nitrogen than for conventional crops is a wiser option.

I could go on about other promoted narratives. Okay…. one more; micronutrients. The story and the products keep changing. I wonder why. A few years ago the promoted narrative was that a single application of a mixture of micronutrients was necessary for all wheat crops, even those not showing symptoms. That was eventually blown out of the water by the superb AHDB project report on micronutrients for wheat. So the selling angle has now changed to a series of applications being required and/or that high yielding crops will only be achieved with their help. Do not fall for it. High yields are a result of healthy soils, good weather and good management. The latter includes using micronutrients only to treat visual deficiency symptoms or persistently occurring deficiencies that will cause symptoms later in the crop’s life. I was surprised by one aspect of the AHDB project: wheat showing a micronutrient deficiency symptom always responded visually to the relevant applied spray but yields were not always increased. This means that the approach I suggest is precautionary.

There are plenty of other promoted narratives; a common one is that organic agriculture is good for the environment. Yet another report has recently been published, this time from Canada, which concludes that this is not true when organic and conventional production is compared on a per tonne basis. Promoted narratives particularly abound for difficult to understand issues such as trying to define the dose of nitrogen required by a specific crop or the impact of weather conditions on yields. Simple values hide the huge variations that occur in real life. I could go on …… but I’ll leave it there!

Leave a comment / View comments


The end of a fairytale

Posted on 03/03/2017 by Jim Orson

I was just starting to write this blog when news came through that Claudio Ranieri had been sacked. Last year, against all odds (well, 5,000 to1), he led Leicester City to the Premier League title. His sacking is indeed the end of a fairytale.

Talking of fairytales, our national press have recently published articles on why UK farming will prosper without subsidies. They all quote the successful adaptation of NZ agriculture to a life without subsidies over the last 30 years. There are some elements of these articles with which I agree but others have a fairytale aspect about them.

There were bankruptcies in NZ when subsidies were first removed in the mid-1980s. Farmers who lost their businesses fell into two camps; those who lived the lifestyle but did not run a business and those really good farmers, especially younger farmers, who had invested heavily. Interest rates soared into the twenties at around the same time as subsidies were removed and there was no way out.

When I first visited NZ around 20 years ago, I was struck by the low level of capital investment in the less productive areas of the business, particularly in and around the farmstead i.e. no posh farmyards, farm tracks, grain storage and barns. However, there was investment going on in productive areas of the business, particularly irrigation. Farmers’ cars tended to be second-hand from Japan (who also drive on the left). Most farmers’ wives were in full time employment and/or heavily involved in the business. This was a vestige from the time when subsidies were first removed and a second income was often essential to keep the business ticking over.

NZ has some climate and market advantages. The main arable area is the Canterbury Plains located to the west and south of Christchurch in the South Island. Here average monthly temperatures are higher than those in East Anglia except for the mid and late summer months. In addition, solar radiation is higher in NZ. This means that crop growth is potentially higher on the Canterbury Plains than in East Anglia, particularly in their autumn, winter and spring. The longer growing season in much of NZ particularly benefits grass production and we all know how they have exploited this to their advantage.

Jim Orson blog -

Average rainfall during the summer months on the Canterbury Plains is a little lower than here in Cambridge. Hence, things can get a bit dry in their summers, significantly limiting their higher potential yields. Many in NZ have overcome this by installing irrigation over the last thirty years or so, not only for arable production but also for grass. Initially there was little restriction in getting a licence for irrigation but things have tightened up significantly over the last 15 years and access to water is getting progressively more problematic. I would like to suggest that the extensive use of irrigation, with cheaper water, has been the major contributor to the increase in NZ productivity that our national press quote and laud. Unfortunately, such an extensive use of irrigation with relatively cheap water is not available to the UK grower.

Jim Orson blog -

On the Canterbury Plains it is not unusual for wheat to receive 100mm-125mm of irrigation a year. The average response is approaching 4 t/ha. The irrigation of wheat is not only a reflection of the cost of water but also the higher potential yields on the Canterbury Plains and that their wheat prices are higher. This is because NZ does not export cereals and so the price of any competing imported wheat has to include the transport costs to what is an isolated part of the world. This provides an advantage to the NZ grower of at least £10/t over world prices. The wheat price is currently around £170/t in NZ.

It is worth pointing out that wheat is often a break crop on the Canterbury Plains. Over the last 30 years NZ has done a great job in building up its herbage and clover seed production. In addition, irrigation has been a significant factor in enabling the establishment of a very significant area devoted to the production of small seeds for export, such as those for horticultural and forage crops. This diversity in cropping has enabled NZ farmers to continue to employ sensible rotations. Over the same period the herbage seed area in the UK has declined significantly and we are only now rediscovering the benefits of rotations.

An issue widely mentioned in our national press is that, without subsidies, our arable input costs, such as seeds, fertilisers and sprays, will go down. This may be a fairytale because, overall, these input costs are equivalent to those in NZ and have been throughout the time I have been visiting that country. Surprisingly, if anything, seed prices tend to be higher in NZ. Some NZ farmers say that their farm machinery costs more than ours but others disagree. This apparent contradiction may be partly due to the swings in exchange rates. Land costs appear to be approximately the same but there are few short term tenancy agreements in NZ.

Another fairytale element of the articles in our national press is the comment that UK farmers have not been keen to adopt new technology over the last thirty years because they have somehow been featherbedded. This, in my opinion, is a contemptuous slur. For instance, the rapid increase in the yields of NZ wheat over the last twenty years has been due to them adopting approaches that were established in the UK in the 1980s.

It is clear that NZ agriculture has not only survived the loss of subsidies but has emerged as a dynamic industry. Their arable industry has done this by exploiting their natural advantages, developing overseas markets and, sometimes, learning from others. I believe that our own industry is equally dynamic and hope that identifying and exploiting its natural advantages and expanding its market opportunities is sufficient for it to thrive in the future. A much more informative document on the impact of the removal of subsidies on NZ agriculture can be obtained by typing ‘farm subsidy reform dividends by Ralph Lattimore’ into your browser.

Leave a comment / View comments


The return of nature

Posted on 20/02/2017 by Jim Orson

I have nicked the title of this blog from Jesse Ausubel of the Rockefeller University in the US. He has long held the view that technology liberates the environment. His papers include some on agriculture and forestry but there are also many papers on other industries, all with this same overriding conclusion.

The basis of his argument is the generally accepted thesis that agriculture has been the greatest destroyer of nature. It is quite clear to me that the initial decision to cultivate a natural habitat has by far the greatest impact on nature. How that land is then farmed is of secondary importance. Hence, in terms of supporting nature, the inevitable conclusion is to cultivate the minimum area necessary to feed the world. This is where technology can come in, lifting yields whilst also maintaining or improving human health and the environment.

Ausubel in a recent review quotes a paper by two geographers who conclude that technology has increased yields in reasonably responsive situations which has resulted in the abandonment of marginal agricultural lands. In the former Soviet Union and Eastern Europe this process has released at least 30 million hectares and possibly as much as 60 million hectares back to nature.

Another interesting reference in the same review quotes a paper arguing that if we keep lifting average world yields at the current rate, stop feeding maize to cars (ethanol), restrain our diets slightly and reduce waste, then an area the size of India, or of the United States east of the Mississippi, could be released globally from agriculture over the next 50 years or so. That would make a huge difference to the natural environment.

In the face of such a prize, it is worth asking the question why so many are absolutely committed to preventing any advances in agricultural technology. This is very much a one-eyed view not dissimilar from those who thought encouraging low carbon dioxide producing diesel cars would reduce the threat of global warming without side effects. The world is really too complicated for single interest groups: surely they could think a little more laterally. I realise that they must keep their subscriptions coming in but they must also think of the possible disservice they may be doing to the wider environment.

BiodiversityWe are constantly told that organic farming is better for biodiversity than conventional farming. However, the UK data I have seen suggest that organic arable crops have the same impact on biodiversity as responsible conventional farming but, of course, conventional arable crops produce around 50% more output per unit area. The difference between the systems in the UK, in terms of biodiversity, is down to the value of the clover/grass fertility building crops in organic systems. These can be used to graze sheep and cattle. However, cattle are five times less energy efficient in producing meat than chickens. Hence, the land devoted to fertility building in organic systems may be far more biodiversity friendly if a minority of it was farmed conventionally and the produce fed to chickens (or pigs), with the majority of the area being specifically devoted to increasing biodiversity. I realise that I may be guilty of being somewhat single-minded on this issue because grass/clover leys may have positive impacts on the soil that are not provided by other crops.

I suspect that the green blob hate the word ‘efficiency’ but that word is the key to a better future for humans as well as the natural environment. New technological approaches must be tested and adopted, if found safe, economic and practical. It is really the only way to achieve a greener world.

Leave a comment / View comments


High wheat yields; a rollercoaster?

Posted on 03/02/2017 by Jim Orson

In a recent blog I discussed the fact that the variation in physical yields between varieties in the winter wheat recommended list trials is the same in both high and low yielding situations. My logical conclusion is that variety choice, in terms of percentage output, is more influential on crop output in low yielding situations. I am sure that in the current economic climate of UK wheat production, an extra 0.25 t/ha due to variety choice will be more welcome by a farmer averaging 7 t/ha than by a farmer averaging 11 t/ha? Of course, this assumes it does not cost more to achieve that extra yield.

Comments have been received on this conclusion. It was argued that farms have both low yielding and high yielding crops and also that yields vary between years. However, I am sticking to my guns because there are fields and farms that consistently have yields well above and well below national averages. Also, there are regions in the UK where yields are fairly consistently above or below national average yields.

An example of a high yielding farm is Salle Farms, near Norwich. The graph below shows the progress in winter wheat yields over the last two decades. Yields are up by 2 t/ha whilst the average yields for England and the Defra Eastern Region have barely increased. You will have to attend the upcoming AAB/BCPC conference to hear how Poul Hovesen has achieved this enviable performance. 

Jim Orson blog -

What intrigues me is that the peaks and troughs in yields at Salle seem to be more exaggerated than those in the English and Eastern Region averages. Maybe this is inevitable because yields on individual farms will vary more from year to year than national or regional averages. However, I have done some crude statistics and the peaks and troughs at Salle are far higher. At the very least, the graph shows that high yielding farms are not immune to volatility in yields and are perhaps more prone, in absolute yield terms, to significant year to year variation.

Should this be the case, then it is perhaps straightforward to proffer an explanation. I have been attempting to predict wheat yields in early July blogs each year since 2012. It is a far easier task when there is no significant shortage of soil moisture. This means that one key weather variable can be dismissed. The real challenge is in years when it is dry in the spring and early summer. Has crop growth been largely unhindered or has the lack of moisture had a significant impact on final yield?

Unfortunately for yield forecasting, high yielding years tend to have dry springs and early summers. With less cloud there is more solar radiation to drive yield potential. Hence, achieving high yields is a tightrope act of getting generous supplies of solar radiation whilst ensuring there is sufficient moisture available to enable the plant to process it into yield. In such situations, soil moisture supplies are crucial and high yielding farms have crops with healthy roots growing in healthy and moisture retentive soils. This combination of healthy roots and healthy soils may explain the significant peaks at Salle and also the less significant yield increases in some years when the national and regional crops remain fairly average.

In low yielding years there tends to be more rain in the spring and early summer and as a result less radiation. For instance, the Junes of 2007, 2012 and 2016 were all wetter and cloudier than average. In such conditions, most or all crops have sufficient moisture and provided that they have a full canopy are able to exploit the lower amount of solar radiation. This results in an overall drop in yield and a coming together of yields on typically high yielding and low yielding farms i.e. adequate (but not too much) rainfall in the spring and early summer are a leveller of crop performance. It is worth pointing out that 2001 had a fairly dry May and June but yields on all farms were lower than average because of the inevitable damage done to the soil and roots in the appallingly wet autumn/early winter of 2000 and early spring of 2001. This was the stuff of nightmares.

To be more succinct, good crop and soil management ensures that yield potential is exploited to the utmost in years when it is high, but in years when low solar radiation significantly limits yield potential, there is not much that good crop and soil management can do to compensate. The disappointing aspect of this observation is that whilst good crop and soil management lead to higher yields they do not appear to reduce the variation in yields from year to year, they may even increase it.

To be even more succinct, the answer lies in the soil (and its management).

Leave a comment / View comments


The real organic revolution

Posted on 20/01/2017 by Jim Orson

In 1943 the then Ministry of Agriculture and Fisheries introduced an Approvals Scheme for proprietary insecticides and fungicides in certain chemical groups. This voluntary scheme was for efficacy only and the approved products had a logo on the label indicating that it did what was claimed.Manufacturers or their agents had to pay a non-returnable application fee of 3 guineas for each product. Another world!

The two scanned pages that appear later in this blog show the complete Approved Products list, first published in 1944. All pesticide groups were added over time. The voluntary Approval Scheme continued until 1985 and the annual list of Approved Products was published in what was known as the orange book. By the end of the scheme the orange book was the size of a longish novel. In 1985, the Food and Environmental Protection Act (FEPA) introduced comprehensive statutory controls of pesticides, including efficacy evaluation.

Amazingly, the efficacy based Approvals Scheme preceded any regulations relating to pesticide safety for human health and the environment. Eventually, The Agricultural (poisonous substances) Act 1952 was introduced to protect agricultural workers from the most toxic products by requiring that protective clothing be worn when using pesticides and restricting the hours permitted to work with them. In 1954 the Government established the Advisory Committee on Pesticides (ACP) as a principle source of advice on pesticide safety issues. A voluntary ‘Clearance’ scheme on pesticide safety, the Pesticides Safety Precautions Scheme (PSPS), ran from 1957 for agricultural products; non-agricultural products were included from the mid 1970s. This voluntary scheme was also subsumed into the first statutory controls under FEPA in 1985. It has to be stressed that whilst PSPS and the Approval Scheme were voluntary, every UK based manufacturer sold only ‘Cleared’ products whose uses were typically Approved a year or two after ‘clearance’. It was the advent of imported ‘Non-Cleared’ products that resulted in the introduction of statutory controls through FEPA.

It is interesting not only to look down the first list of approved products but also to look at the names of the companies selling them. Those as long in the tooth as I am will recognise many of the names but I think that Bayer and H.L Hutchinson are the only companies still trading. Bearing in mind that the year of the list is 1944, the inclusion of a German company is hard to understand. I assume that the then Bayer Products Ltd. was trading independently of its parent company! The other companies on the list have simply stopped trading or were subject to company mergers.

Looking down the list makes me grateful for the modern era of organic chemistry (also referred to as carbon-based or synthetic chemistry) which is the basis of not only more efficacious products but also safer products. Organic chemistry is perceived by some as unnatural but in the case of several products in the first approvals list, returning back to ‘natural products’ would have some serious consequences for human health and the environment.

Keep up to date with crop protection and crop production issues by attending the AAB/BCPC conference Crop Production in Southern Britain 2017, kindly supported by Adama. The conference is to be held on 15th and 16th February at the Peterborough Arena (on the showground). Click here for more details. 


Leave a comment / View comments


Page:  < 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 >  Last ›