annular ciphers, keys and decision trees

Annular designs, comprising a set of concentric rings, have been used as keys and ciphers for hundreds, even thousands of years. They arrange and compress information into a compact form that may be  readily portable, for example on paper or light ceramic. Annular designs have been used variously as a secret code, a memory-system, a focus for meditation, a botanical key and a comparator of microbial genomes. 

Why the specific interest? Over the last few years, we have been looking at ways to condense decision trees [1] having many branches, nodes and leaves  into a more compact form. The first attempt, to be described later on these pages, was for a decision tree on environmental risk assessment. Present developments include a decision tree and general guide for use in planning sustainable agriculture and food. 

Browsing a range of sources revealed several devices of this type that were designed for practical usage. Interest arises in the mechanisms by which the user moved from one ring to another. Here is one of them, used primarily as a botanical key.

Ciba-Geigy Weed Tables

A device published 1968 (1975 in English) by the company Ciba-Geigy Ltd, Basle, Switzerland is a classic of annular design. It is a botanical key (Fig. 1). It accompanies a set of exceptional botanical paintings of some major weeds of the world. 

Fig. 1 Photograph of the design from a library copy of the Weed Tables. 

A note attributes text and layout to Ernst Hafliger and artwork to Hanspeter Eisenhut. The design was a supplement to the Ciba-Geigy Weed Tables, a compendium of major weeds of the world. It was found within a box, sat among books in the ‘weeds’ section of the Hutton Institute Library at Invergowrie, Dundee. It was probably bought at the time of the ‘weeds group’ in the previous Scottish Crop Research Institute. 

The key begins in the centre with the seed leaves (cotyledons, one or two), then moves through foliage leaves, flowers, stamens and carpels (Fig. 2) to reach one of the plant families (e.g. Polygonaceae, Chenopodiaceae) arranged on the outer ring. Each family is contained within a segment of the circle defined by radial lines. 

The key would work in the field if it was printed on strong card or something similar, pinned in the centre so that the whole could be moved round repeatedly until the unknown plant being examined could be linked to its family. In that form it would not be that far removed from a mediaeval cipher with independently moveable rings. 

It could also be a great teaching aid in those few remaining places that still teach about weeds. 

Fig. 2 Colours and symbols are used to help the reader navigate through the options from the centre to the perimeter.

Comment

The botanical key in the Ciba Geigy Weed Tables works (as do most keys) by radiating from an initial (either-or) choice to traverse a number of options until the final decision is made on the plant family of the (unknown) weed in hand. In contrast, most decision trees begin by quantifying many input attributes, then narrow down the options to one final choice. Both this key and decision trees in general can in principle be worked either way.

The Ciba-Geigy weed key shows that a mass of information and instructions can be arranged into a compact and easily understood guide. Its use of colours and symbols make it appeal to some as a work of art, to be framed and hung on a wall. It lacks some characteristics of decision trees – the capacity for balance and weighing of attributes or  explicit cross links between different branches – though these are not needed for it to fulfill its purpose and could in any case be introduced if a computerised version were made of the key.

This weed key demonstrates (to this writer) a stunning, modern representation of the ancient design of the annular cipher. ‘Modern’ … but this was published more than 50 years ago. The authors, designers, artists and publisher of the Weed Tables viewed weeds as special plants that came to coexist with agriculture, not simply some green stuff that had to be eradicated.

[Descriptions of other designs to follow ….]

Sources

[1] For more on decision tree and an example on this web site: Greening with decision trees 

[2] Ciba-geigy Weed Tables. A synoptic presentation of the flora accompanying agricultural crops. Hafliger, E., Brun-Hool, J. 1968. Ciba-Geigy, Basle, Switzerland. First edition in English 1975. The design of the cicular key is attributed to Hanspeter Eisenhut. 

[3] Images used here are phone snaps taken by the author from the copy of the Weed Tables in the James Hutton Institute Library, July 2019.

[4] For an idea of the scope and quality of the illustrations, search online for Ciba-Geogy Weed Tables. The box is still available to buy second-hand. Some vendors show images.

Author/contact: geoff.squire@outlook.com or geoff.squire@hutton.ac.uk

form line, form square? … naargh just mix it!

Formal and informal mixed cropping. Mixed corn and mashlum (oats, beans) preferred historically in Scotland, seed mixed not sown in lines or squares. By mid-1900s, covering very small areas of cereal land. Dredge corn from SW Britain.  Unintended mixed grain from volunteer weeds. Mixes grown as a safeguard. Lessons from history.

Archaeological evidence from many landscapes across the globe shows agricultural land divided into geometric shapes. Linear features may have been constructed as drove-ways to move stock from one piece of land to another; or for cultivation by teams of animals dragging a plough that was difficult to turn. Squares or or other shapes with conserved side-length, are preferred when something has to be contained, such as stock animals or valuable crops that can be surrounded by a wall or fence.

Similar features occur when more than one species of crop is grown in a field. Such intercropping or mixed cropping is widely practiced in many agricultural regions. Smallholder gardens will often consist of small blocks, sometimes even single plants, grown close to each other, sometimes under the shade of a tree-crop. Perhaps the most widely observed configuration is that of lines or rows. One species might occupy one or more adjacent lines, then another species then back to the first species, as in the example below of an intercrop of chickpea and sunflower [1]. 

Chickpea field in which lines of sunflower have been sown, Burma (Myanmar), image by curvedflatlands.

Not all mixed crops are grown in formal configurations. Seeds can be mixed in the bag or mechanical sower and broadcast on the land. Two or more species then emerge together to form a mixed stand.

Also, unintended mixtures can occur when seed dropped on the soil by previous crops emerges in a later one (see below). Whether unintended or planned, simple mixtures have been recorded in agriculture since records began.

A new dawn for mixed cropping in Atlantic Europe?

Three factors need to be assessed when considering the (re)introduction or expansion of mixed cropping. One is whether a biological advantage results from growing the species in a mixture: if there is, the grower gets more from the land or resources than they would if the crops were grown alone over the same area. A second is whether the mixture provides a convenience: even without a biological advantage, it might simply be easier for sowing and harvesting to grow two or more crops in a particular configuration, especially if the grower wanted a varied output (e.g. cereals, legumes, fruit, vegetables) from a small plot of land. The third is whether the mix provides a safeguard or security against unexpected events: here, a biological advantage and ease of management may combine to ensure something is produced.  

The type of mixture used in previous times may also be a practical guide to what might still be feasible. In Scotland, and elsewhere in Britain, the most common sown mixtures from the 1700s to the early 1900s were intended for hay and grazing. They were rarely ‘grass only’, but comprised grasses, legumes and other broadleaf species in proportions varying with the intended use [2]. The legumes in the mix, the most abundant being white and red clover, fixed much of the nitrogen used by subsequent grain crops.

Also references are repeatedly made to assorted mixes of corn and grass, where barley or the landrace bere was sown as a ‘nurse’ for the more valuable and longer lasting hay or grazing mixture [3].

Mixed arable crops (no grass) were also mentioned in sources from the 1700s and 1800s, mainly as sown seed mixtures, very rarely if ever as line intercrops. But by the time formal agricultural census began in the later 1800s, sown crop mixtures such as mixed corn and mashlum were grown over a very small area. 

Mixed corn, dredge corn and mashlum

The two most widely grown crop mixtures in the north of Britain go under the names mixed corn or mixed grain and mashlum. Mixed corn consists of two or more cereals, barley and oats for example, while mashlum consists of a cereal and a grain legume, typically oats and beans (Vicia faba). Mashlum reached its 20th century peak during WW2 (Fig. 1). The subsequent fall but continued usage of mashlum was documented on the Living Field web site [4].

Mixed corn or mixed grain appeared as a separate entry among grain crops in the Agricultural Census of 1929 [5]. Its area expanded and contracted over the next 50 years but generally remained less than 0.05% of the combined cereal area (Fig. 1). There is little information of why mixed corn was grown and also why its area was so small. Oat dominated the cereals in the earlier part of the period shown, then gave way to barley and wheat. 

Fig. 1. The areas sown with mixed corn and mashlum in the Agricultural Census for Scotland [5]: mixed corn not identified from other cereals before 1929 and after 1978; mashlum grouped with other forages before 1944 and after 1960. Over the period shown, mixed corn comprised less than 0.05% of the combined cereal area.

Cereal mixtures grown elsewhere in the UK offer some explanation. A mixture of barley and oats named Dredge Corn was a feature of arable in the south west, mainly in Cornwall [6]. Its area was uncertain due the fact it was returned as ‘barley’ before 1919. As the quote at the top of the page implies, it was used as a safeguard, to ensure a reasonable yield under most conditions. It had a place in the crop rotation, sometimes replacing oats, sometimes barley, and was used in particular for a whole crop feed when the soil or the year was not capable of producing a pure crop of quality to sell as grain.  The proportions varied but were typically two parts oats to one barley. Wheat was added in some cases, making a three-part mixed grain.

While it was certainly grown as a safeguard, it was also attributed biological benefits [6]. It was stated to produce more grain than barley alone and generally more than oats alone, oats being deeper rooted and thereby accessing more resource. In dry years, barley grew to fill the ‘gaps’ left by dying oat tillers. The straw was of higher feeding value than the individual crops, due to better overall structure. But perhaps most relevant to the Atlantic climate, the mix was better able than barley or oat alone to withstand the forces of wind and rain to flatten the crop.  Similarly, one source reported that another variant – a mix of white and black oats – gave a greater yield (of straw) than either alone – the stronger stemmed white supporting the finer stemmed black. 

Despite such reports from farmers, there is little hard information on the yield advantage given by mixtures sown on the fringes of Atlantic Europe. They might have given the 1.1. to 1.3 times advantage widely recorded for intercrops, but without the experimental data from the 1920s or earlier, there is no way of knowing. 

Sown as a seed mix in April, no fertliser or pesticide: (left to right, 1 to 4) the bere barley grew quickly (1), then oat pushed through (2), bere matured first (3) and finally oat (4).
The widespread occurrence of unintended mixtures

It is the nature of small-grained cereals – oats, barley, wheat – to drop seed before or at harvest. The seed remains in the soil and, depending on conditions, emerges in a later crop. Today, such crop-weeds are commonly termed ‘volunteers’ [7]. The sown species and the volunteers in effect form a mixed crop (image below for wheat in barley). Other crops also generate volunteers. Those of oilseed rape are the most visible, but potato and field bean (Vicia faba) often produce mixed crops with cereals, though these broadleaf species may be really controlled by selective herbicides today. 

Unintended mixed crops have been a feature of cereal lands probably since domestication. If the intended product was whole-crop cereals to be fed to stock, then they would have been seen as a benefit – free seed. However, they may also create a problem. They are an unwanted nuisance when they have to be separated from the crop, for example when a pure seed-harvest is needed, and they could harbour and carry over disease. Volunteer cereals are not a recent problem: records from the 1500s [8] on oats relate “that they grow amongst wheat and barley without being sowen, as an evil and unprofitable thing ..”.

Maturing barley crop, golden brown, in which volunteer wheat (upright heads, dark grey-green) has established; younger, still green plants growing in the wheel lines.
Conclusions

Mixed corn, and mixtures of corn and grain legumes, have been recorded for centuries in Scotland, and more generally in Atlantic Europe, but their benefits have not been adequately quantified. Where they were grown, it was as broadcast seed mixtures rather than line intercrops. By the early 1900s, they were minor crops. After the 1940s, agriculture was aiming for the high yields promised by intensification: mixtures almost disappeared. 

Current reappraisal of crop mixtures might perhaps examine why in the early 1900s they never became major crops and why they were rarely grown as line intercrops.

Sources

[1] Photograph of chickpea-sunflower intercrop taken in Burma (Myanmar). Details on curvedflatlands at Mixed cropping in Burma.

[2] Seed mixtures for hay or grazing from the 1700s to the early 1900s are described in a related article on curvedflatlands: Grass mix diversity a century past.

[3] Crop mixtures are frequently referred to by Andrew Wight in the Present state of husbandry in Scotland (1778-84. Volumes 1 to 6), where one of the components (usually bere or barley)  is most commonly a ‘nurse’ crop, protecting the others, which are usually grass mixes (grasses, legumes and other broadleaf species) to be used for hay or grazing. 

[4] Mashlum, Scotland’s cereal-legume seed mix, still occasionally grown, is described on the Living Field web pages at Mashlum – a traditional mix of oats and beans  and Mashlum no more! Not yet.

[5] Data in Fig. 1 are taken from the online Agricultural Statistics in Scotland one of the Historical Agriculture Publications on the Scottish Government web site. Based on the 1965 census, Coppock created an atlas in which the small area sown with mixed corn was noted with the comment that it was ‘not grown in the great majority of parishes’. Ref: Coppock, JT. 1976. An agricultural atlas of Scotland. John Donald, Edinburgh.

[6] Borlase, W. 1925. Dredge corn. In: Farm Crops, Vol 1, pages 265-269.

[7] Volunteer weeds, derived from crops, and presently common in Scotland  are described at the Living Field web pages on Crop-weeds.

[8] Quote on oat from L’Agriculture et Maison Rustique by Estienne and Liebault, 1593 edition. Further details and origin on the Living Field web pages at: Ready, steady mundify (your barley) and  The Library of Innerpeffray.

 

 

Arable trends – positive, negative and neutral

There was no question – following the privations of WW2 – that the arable production systems in Scotland, and indeed all of the UK, had to change. It took the Agricultural Expansion Programme a decade or more to reorganise, then from the 1960s yield per unit area (t/ha) and total output increased steadily by almost threefold due to developments in machinery, fertiliser and new crop varieties. By the 1980s, chemical pesticides  were increasingly used  to combat a rise in weeds, diseases and insect pests, which were themselves thriving on the high nitrogen and carbon contents of the improved crops. But by 1990, yield and total output of grain and other major products levelled and remained so for the next quarter-century. This rise and subsequent levelling occurred in many parts of the world. 

Change despite level output

Not all else has been stable over the last 25 years. Pesticide use has continued to rise and biodiversity to fall. Home production comes nowhere near feeding the people. Economics relies on exports and food security on imports. Yet the future will at some point have to rely again on home production – there is no getting away from it – and nearly all of that production will be in fields. What next then! depends on appreciating how things are now. 

Some of the main positive, neutral and negative trends over the past quarter-century and earlier are listed below in the following main categories: 

  • Agronomic inputs – the addition of fertiliser, pesticide, fuel and other external or imported inputs that drive current arable systems. 
  • Yield and economic outputs – the tonnage and quality of products that come off the field, their markets and profitability.
  • Environment – soil, food webs and biodiversity crucial to the functioning of fields; losses of soil, water and chemicals to the wider environment.
  • Food security – the contribution of arable cropping to the food consumed by the population, the capacity to deliver food security in time of global calamity and reliance on exports.

Not all agree what is positive and what negative. Here, positives support long-term food security, a healthy environment and a viable rural economy, all of which are interdependent. 

The summary below is of a work in progress, at this point concentrating on trends evident from research at scales of field and landscape [1] and official  government databases and web sites from which broad trends and current status can be estimated at regional scales [2]. 

Trends in some topics are not yet included – rural employment, plastic and plastic waste, arable-grass integration, gross margins, risk, education and further training among them. The growth of micro-production and ‘off the grid’ sectors in the form of cooperatives, collectives, urban farming, farmers’ markets, farm shops, etc., is hard to gauge but future food security may depend on the continued growth and influence of this sector. 

Main positive trends

The main positive trends over the past quarter century are in agronomic (fertiliser) inputs and diversification of both products and supply chains. Few if any positive trends occurred in environment, food security and yield.

Agronomic inputs
  • Phosphate fertiliser inputs have continued a major long term decline both in the area of crop treated and the amount per unit area, resulting in total applied phosphate being half in recent years what is was in the 1960s.  
  • Nitrogen (N) – the major rising input driving intensification – has declined to about 80% of its 1990 peak, mainly due to set aside, nitrates directives and price rise.
  • A major part of the N fertiliser decline occurred in winter cereals which had been over-supplied by the late 1980s – a corrective trend taking 25 years.
  • In consequence, nitrogen and phosphate wastage has been reduced as input came closer to offtake, but little scope remains for further savings in current grain crops as specific mass-N and mass-P ratios (stoichiometry) are needed for saleable products. 
  • As a result of the above trends, the nitrogen-phosphorus (N:P) ratio in fertiliser inputs (a useful broad-scale indicator of agro-ecosystem status) increased from its low of 2 in the 1960s and is now stabilising at around 6 which implies a reasonably balanced N:P input. 
  • Nutrient use-efficiency (yield per unit input) for phosphate increased more than three-fold from the 1960s and continued to increase over the past 25 years;  the corresponding metric for nitrogen increased slightly after the 1990s. 
  • GHG emissions in arable (depending largely on nitrogen fertiliser) were  initially cut after 1990 due to set-aside and EU nitrates directives but have been resistant to further reduction i the past decade; solutions to achieving committed targets would include a shift to low-input and N-fixing crops such as grain legumes in arable and grass-clover mixtures in grassland, but mandatory implementation may be necessary.
Diversification of crop products
  • Greater local production of a range of products is an increasing trend, e.g. (with livestock sectors included) cheese, beer, gin, rapeseed oil, botanicals, esculents, meats, landrace-food, soft fruit and vegetables. Yet most arable produce still goes to large-scale markets for livestock feed, alcohol and biofuel.
  • Rise in short food supply-chains – farmers markets, farm shops, cooperatives, but this sector is still a very small proportion of total production. The percentage of the population fed by short supply chains is uncertain.

MAIN NEUTRAL TRENDS

The main neutral trends are in crop yield and total output. The are no  neutral trends in agronomic inputs, environment or food security. (Here, neutral means absence of change in the last quarter-century in something that had changed previously.)

Yield and output
  • Arable and grass surface areas have fluctuated since records began in the mid-1850s, but areas sown to the main cereals have shown no major trend since the 1990s.
  • Yield per unit area over most of the arable sector levelled in the 1990s and has hardly increased since (possibly by 10% over 25 years); exceptions include a rise of yield in oats, which covers the smallest area of the cereals. 
  • Average yields remain well below the highest farm yield and predicted maxima, yet remain high compared to similar crops in other parts of the world (i.e. in the category short-season cereals, temperate, unirrigated), mainly due to the ‘long cool summer’ effect in the NE Atlantic zone.
  • Home production of grain legumes showed some rise from the low point of the 1930s but is still very small (approx 1% arable) compared to legume production in many parts of the world, and accordingly imports supply most of the plant protein eaten by people and livestock .
  • Diversity of crop types increased during intensification (1960-1990) as winter variants of the cereals appeared, and has not since been lost – arable cropping here, while dominated by barley, is still relatively diverse compared to global standards in terms of the number of different crops that can or could be grown.
  • Bad-weather years such as 2012 and 2018 caused a dip in output but not a catastrophic loss –  climatic variation as currently predicted is unlikely to have major negative effects here (provided agriculture remains diverse and reverses the negative trends listed below).  
MAIN NEGATIVE TRENDS

Main negative trends are in pesticide inputs, environment and food security. 

Agronomic inputs
  • Pesticide usage has doubled in most arable crops over the past 25 years despite level yield (pesticides assessed by ‘spray-area’ of formulations or active substances rather than mass) and so pesticide application per unit yield has increased; possible signs of levelling of fungicide application in spring barley.
  • Despite long-established EU strategies to reduce reliance on pesticide, Integrated Pest Management has not been widely taken up in mainstream production (and so is considered a negative rather than neutral trend); integrated (e.g. LEAF) and organic practices are still a small fraction of total cropped area and output; UK-wide IPM policy introduced belatedly and half-heartedly with little effect.
In soil and biodiversity
  • Soil quality (health) is declining in high-input areas due to a range of practices established during intensification (1960-1990) and maintained since; while soil carbon by weight (%C) is down to 1% in some fields, %C tends to be stabilised and not at immediate risk where grass leys occur in the crop sequence and extreme tillage is avoided, e.g. spring cereal-grass systems; but overall soil degradation and erosion risk remain high in arable regions. 
  • Crop-wildlife balance in terms of the sharing of energy and living matter in the ecosystem has moved increasingly to crop, causing further major loss of species, populations and habitat, a trend occurring both in fields and across the landscape; extreme field cleansing evident in many areas brings no benefit to crop yield; high-N plant material (essential for the food chain including beneficials ) is now rare in fields;
  • Impact of loss of beneficials as pest control agents (see note on IPM above) is uncertain while pesticide usage continues to rise.
  • Weed balance showing major long term shift to grasses and away from legumes and other broadleaves. 
Food supply chains
  • Local production of food is far from satisfying population needs for carbohydrate, plant protein or vegetables; home production more geared to alcohol and feed; this despite national policies following WW2 to raise yield for the aim of achieving food security. (The balance of local vs imported food will be examined in later articles.)
  • Since the 1960s (approx) the country has relied increasingly on imported carbohydrate and plant protein (animal feed protein also); the resulting long supply chains are inefficient in use of resources, increase GHG emissions and in many cases degrade external ecosystems.
  • Production is unprepared for – and will be unable to ensure survival through – imposed calamities, either from human folly or aggression (blockade, war) or natural cataclysm (volcanic eruption). (This could be interpreted as a 100-year neutral trend since the country was in a similar position at the start of WW1 and WW2, but is classed as negative because the stated aim in the late 1940s and 1950s was for self-sufficiency.)
  • Farming is in general financially squeezed and receiving nowhere near its fair share of the lauded successes of Scotland Food and Drink. The profitability of much of farming relies on subsidy.
  • The level of agricultural planning, e.g. targets for home production, subsidy to guarantee results-based environmental standards, mandatory reduction of inputs (e.g. in fertiliser and pesticide, emissions, etc.) has looks to have  diminished since the postwar expansion programmes. 
  • The Common Agriculture Policy has supported some major farming sectors, but in many areas of concern has been more counter-productive than helpful, a situation much the same in Scotland as in the UK and most NE Atlantic agro-ecosystems; CAP Greening has not resulted in much greening. 

Next? 

The corrections to the over-provision of mineral fertiliser in the 20th century show what can be done through a combination of EU directives, national strategy and local initiatives.  Can similar action be taken over negative trends in food security and environment? In principle it can. But it is unlikely to happen while cheap imports remain the general preference and wastage is tolerated. Subsidy has failed so far to give adequate support for local food production, environment, small producers and farming-food cooperatives. Mandatory measures may be necessary to curb emissions and pesticide. 

Yet the position is at this point reversible. Most damaged soils can be repaired, food chains shortened, local consumption raised, pesticide brought under control. Farmland habitat and biodiversity can still be restored without loss of yield. But support needs to be tied to results, in healthy food as well as environment. The future should not be left to the big players in arable farming, food and drink. 

[Options to be examined in later articles…]

Sources, references, links

[1] Information on in-field and landscape processes from which trends were defined comes from research by the author and colleagues in the arable-grass regions of Scotland funded by Scottish Government. Examples of recent research papers looking specifically at trends include: Squire, 2017. Defining sustainable limits during and after intensification in a maritime agricultural ecosystem. Ecosystem Health and Sustainability https://doi.org/10.1080/20964129.2017.1368873; Squire, Quesada, Begg, Iannetta, 2019. Transitions to a greater legume inclusion in cropland …. Food and Energy Security https://doi.org/10.1002/fes3.175 (both Open Access). 

[2] The Scottish and UK governments provide many sources of data online or available in hard copy, mostly at national and regional scales. Examples of the sources used to derive many of the trends summarised above are given on this web site at Citizen’s Jury at the Scottish Parliament/ 3 .

[Online 8 July 2019; minor edits 15 July 2018; page to be amended as necessary in light of new information; any major amendments will be noted.]

Author/contact: Disclaimer This article presents the views of the author, G.R.Squire, geoff.squire@outlook.com.

Funding  The author currently has honorary (unfunded) status at the James Hutton Institute. A background knowledge of trends in agricultural production and environment in Scotland was gained in past years through funding from the Scottish Government Strategic Research Programme.

Citizens’ Jury at the Scottish Parliament

A Citizens’ Jury was assembled to deliberate on a major topic of agriculture, land use and food security. They were to spend a weekend at the Scottish Parliament in Edinburgh from 29-31 March 2019. My role was to advise the jurors on current issues, answer questions and draw attention where necessary to reliable data.

Latest …. report and short film prepared by Scottish Parliament now available …. wide selection of online data sources collated on page 3 … see bottom of page for links 

The event was a reassuring experience – a group of people previously unknown to each other coming together, learning individually and together, absorbing complex issues and debating constructively, being courteous to each other and giving due weight to all opinions.

The Friday evening began with an explanation of the event – the jurors did not know the exact topic until then, other than it was to do with  ‘environment’ – and some insight from a visiting speaker on the need to judge reliable information, rather than hearsay and false news, when reaching conclusions .

Perhaps the most important result of the Friday evening was for the jurors to agree a set of rules as to how the discussions would be conducted. Simple guidelines such as ‘there should be no interrupting or talking over another person’ would have at one time seemed natural for such as event, but given the manner in which public argument is so often carried out, the jurors as a whole wanted to make it clear that the views of all should count and be heard.

The second day began with a series of talks, including the opener by me (see link to page 2 below), and  another from Kirsty Blackstock of the James Hutton Institute, Aberdeen. At various times over the weekend, the jurors got the chance to discuss the main questions in three groups of 7 – 8  and also to raise points in general assembly. Each group had a facilitator whose role it was to guide the jurors without leading them down any one path. In an extended session on the Sunday, the jurors heard from and could question people who manage land (farmers, smallholders, etc.) or are responsible for governmental and private policy on land.

Those from the Scottish Parliament who ran the event had prepared well, notably in providing examples of the support given to agriculture and environment. Detailed case studies for Switzerland and Australian had been prepared as a base for comparison with the current (and the  future) position in Scotland.

The need for reliable information

It became clear over the weekend that a visiting specialist at an event like this needs to guard against personal opinion and bias. My view is that, despite irreversible change to land and vegetation since the retreat of the last ice, sustainable production is possible at the same time as restoring lost ecological function. ‘Sustainable’ here means continuing to produce food and other economic products from the land for a further few thousand years.

My (continued) view is that to achieve sustainable production needs major change, after which not all interests will be equally satisfied.  A more equal balance needs to be struck between the various outputs – drink and food, economic returns, soil and food webs, wider biodiversity and environment.

Agriculture has to return to producing most of the food eaten in the country, and this includes plant carbohydrate, protein and nutrients such as minerals and vitamins. Agriculture cannot do this alone – it needs buy-in from people, government policy and the supply chains that connect it with markets, retail and consumers. Food production has in the recent past come into competition with feedstock industries and has generally lost because cheap, plant-based food can be imported.  As a result, the country would last months maybe, probably weeks, in the face of any serious blockade or natural calamity that prevented food imports.

Summary of data sources with links

Any solution for the future needs to take account of many sorts of information – on crops and livestock, economics, markets and supply chains,  on soil and other essential natural systems and on impending change in weather, climate, international markets and food policy. To advise on all this needs not only active research into production ecology and economics, but also familiarity with a very wide range of background information.

The types of data that typically consulted and analyse are summarised on a separate page (3 below).  The data are held mainly on government web sites (Scotland, UK, EU, etc.) and are generally downloadable free of charge. One of the great benefits of the web is that such information is now accessible. When I started work on the Scottish scene 25 years ago, you had to be based near a good technical library or else buy or beg hard copy through the post.

Topics include: the general environment in Scotland; agriculture, land area and crop yield; land use and soil; economics, imports vs exports, EU subsidy and greening; inputs such as fertiliser and pesticide; greenhouse gas emissions, weather and climate; land ownership; natural environment and biodiversity.

Opinions given at the event were based on previous careful sifting and analysis of such information together with research on the historical trajectories of agriculture and land use (which are more difficult to quantify but are increasingly made available though online libraries).

What happened next?

The people running the event at the Scottish Parliament have prepared a report of the event, published on 11 July 2019 and viewable at this link:  Scottish Parliament Citizens’ Jury on land management and the natural environment.

A short film is available at this link: Citizens’ Jury on land management.

Contact: geoff.squire@hutton.ac.uk

Further pages

[2] Presentation by G R Squire at the Citizen’s Jury event 30 March 2019 (to be uploaded)

[3] Sources of information on agricultural census, land use, imports/exports, CAP and greenhouse gas emissions which outlines the range of data that should be examined before reaching conclusions of the current state of food security and environment.

[Article first online 4 July 2019, minor amendments and new pages added up to 2 November 2019]

The 2018 summer drought

The 2018 summer of low rainfall was one of the driest on record. Cereal grain harvest dipped but did not fail, loss of production caused more by conditions in the previous winter than the summer drought. A further example of grain harvest’s resilience to untypical weather in the north-east Atlantic. 

This extended version of an article originally published on the Living Field web site [1] looks in more detail at the rainfall patterns of early summer last year in lowland Scotland.

The long summer of unusually low rainfall in 2018 parched much of the grassland and stunted many of the cereal crops in eastern and central regions. The wheat and barley appeared to suffer in many places. A record low for grain output looked set to happen. Yet the yield figures suggest a remarkable resilience to what turned out to be unusual weather for the region.

First the rainfall …. How low was it?

Daily rainfall records for East Scotland

The Met Office provides several valuable series of historical weather data. The analysis here uses the daily rainfall series for regions of the UK from 1931. The method of deriving such regional records by combining site by site observations was described by Alexander & Jones in 2001 [2]. The rainfall series has been continually updated since then. The Met region ‘East Scotland’ is the one where most of the wheat, barley and oats are grown.  The period in 2018 from April to the end of August joins that of several other years in being unusually dry – 1955, 1976, 1981, 1984, 1995, and 2003 all had rainfall below 200 mm (Fig. 1a).

Fig. 1 Rainfall between 1 April and 31 August for the East Scotland region in all years since 1931, showing (a) total over the period, left; and (b) days with less than 1 mm, right. The line is the value in 2018. Years of low summer rainfall are arrowed. Data source: Alexander & Jones, 2001 [2].

There is little sign of any major trend in either low or high rainfall over the main summer period. Many of the other years after 2000 were much wetter than 2003 and 2018. The highest rainfall of recent times was the very wet 2012, which had more rainfall than all other years except two. What distinguishes 2018 is the pattern of rainfall.

Fig. 2 Cumulative rainfall from 1 April for selected years showing the rapid rise during May in 1976 and 2003, a slow rise after April in 2018 until mid-July and the driest year 1984. Data source: Alexander & Jones, 2001 [2].

Many of the years having low summer rainfall had a fairly wet May, as evident in the steep rise in cumulative rainfall in 1976 and 2003 in Fig. 2. The same pattern occurred in the dry 1955 (not shown). This rainfall in May fills the soil enough to allow the crops to last through a dry June and July at which point most of the season’s growth has occurred.

2018 had a wetter April then most other dry years but then low rainfall until late July. Although 1984 had the lowest rainfall overall, 2018 had the lowest from late April through to mid-July, which is when the solar income is large and when the crops are bulking. Summer rainfall in 2018 would have been less in total than in 2003 if it had not been for that rain in late July and early August. A day by day view of the rainfall in 2018 compared to 1984 and 2003 is given in Fig. 3.

Fig. 3. Daily rainfall from 1 April in three contrasting years: 2003 and 2018 had a similar total rainfall whle 1984 was the driest over this period.

So did this low rainfall during crop bulking have an effect?

Yield figures for 2018

Each year the Scottish Government provide absolute records of crop-areas (i.e. all fields counted) and estimates of yield per unit area based on data from a range of sources. The final estimates are published in December [3].

The wet year of 2012 provides a comparator: most crops but particularly wheat, oats and oilseed rape produced a low yield per unit area that year because of waterlogged soil and low solar income [3]. Total cereal output was lower that year than in any other year of the past two decades.

The records show 2018 yields were no worse. Wheat yield per unit area (t/ha) was down to near the 2012 value but most of the other crops showed little fall in yield (Fig. 3). When expressed as a percentage of the average of recent years, the simultaneous dip among crops in 2012 was not repeated in 2018 (Fig. 4). Spring barley, the most widely grown crop suffered a minor fall to 98% of the long term average.

Fig. 3 Grain yield of wheat (red), oats (black) and oilseed rape (blue) over the last 20 years shown as weight harvested (left) and percent of average (right).

Was anything different about 2018. Total cereal output (the sum of wheat, barley and oats) was low, in fact just above the 2012 value, but this was due to reduced land areas sown with cereals, mainly winter barley which was sown in the autumn of 2017 before the summer drought of 2018. Sources in [3] state ‘Winter barley area dropped by a fifth due to poor weather conditions. This, along with a four per cent drop in yield resulted in production decreasing by 24 per cent.’ The greater effect therefore occurred before the winter and ‘was a result of the difficult weather conditions in late 2017.’

It appears therefore that yields per unit area – the best guide to the effect of weather on the summer bulking conditions – were not strongly affected by the 2018 drought.

Caution is needed because the yield figures are an estimate, i.e. not measured for all crops. Some crops were not harvested for grain at all, where the weather ‘resulted in a number of farmers choosing to whole-crop due to the low yield and quality [2].’ (To ‘whole-crop’ means to take all the grain and straw together for feed without separating the grain.) Some of the poorest yielding fields might have been removed from the estimate of yield since whole-crop cereals would not have been included in grain yield inventories.

Could grain yields collapse in this region?

Drought leads to zero crop yield in many countries. Even in parts of Australia, where standards of agronomy and resource-use are high, recent droughts have led to total failure of cereal crops that are not irrigated.

So could crop failure occur here? In principle yes. But it would have to be a much drier year than any since the records began in 1931. Given there is no discernible trend towards low summer rainfall and that most years between 2003 and 2018 were wet, and two of those years – 2014 and 2016 – produced among  the highest mean yields ever in this region, there are certainly no indications that summer droughts will become a feature of the Atlantic maritime cropland.

Winter flooding may come to impose more severe limitations to agricultural production …. [4].

Sources, links

[1] The Living Field web site at Resilience to the 2018 drought.

[2] Daily rainfall series from 1931: Alexander, L.V. and Jones, P.D. (2001) Updated precipitation series for the U.K. and discussion of recent extremes, Atmospheric Science Letters doi:10.1006/asle.2001.0025. Further information at the Met Office’s Hadley Centre web site: https://www.metoffice.gov.uk/hadobs/hadukp/

[3] Cereal and oilseed rape harvest: 2018 final estimates:  https://www.gov.scot/publications/cereal-oilseed-rape-harvest-2018-final-estimates/ Published 12 December 2018. See also https://blogs.gov.scot/statistics/2018/10/04/2018-scottish-cereal-harvest/

[4] Links to Living Field articles on high rainfall: The late autumn floods of 2012, Winter flood,  Winter flood … continued and Effects on corn yields of the 2016 winter flood.

Author/contact: geoff.squire@hutton.ac.uk or geoff.squire@outlook.com

Funding  The author currently has honorary (unfunded) status at the James Hutton Institute. A background knowledge of crops and climate in Scotland was gained in past years through funding through the Scottish Government Strategic Research Programme.

Grass mix diversity a century past

Innovative seed mixtures from the early 1900s based on functional properties of species. Legumes around 20% of seed mix by weight. Increasing complexity to suit purpose and longevity of the sward. De-diversification in the last 100 years. One of a series of articles on crop-grass diversification.

Diverse grass fields were once a common feature of the agricultural landscape. Mixtures of grass, legumes and other species were widely trialled and adopted in the Improvements era after 1700 [1]. Mixtures were promoted throughout the late 1800s and early 1900s, the topic of this article.

The aim of mixtures was to provide a balanced diet for livestock and to regenerate soil condition and fertility. Nitrogen-fixing legumes in mixtures had the specific roles of enriching soil with nitrogen, before mineral fertiliser came to be widely used from the mid-1900s, and offering livestock a high-protein bite compared to the grasses.

Most traditional meadows have now been converted to fertilised grass or crop. Much of the grass now grown for hay or pasture consists of one or two grass species, with occasionally white clover and often some noxious weeds. Legume forages are now uncommon. Managed grass is usually supported by mineral fertiliser and by imports of high-protein legume-based feed supplement.

Grassland. Shapinsay, 27 May 2019

Change may be afoot! Recent EU funding rounds have brought together researchers and specialists to design and trial new food and feed systems which aim to reverse some damaging trends both in the field and the wider food supply chain [2]. Part of the solution is a re-diversification of agriculture.

To explore some of the main current themes, the Living Field [3] and this web site are running a series of articles on diversification in land use and food production. Many of the forgotten practices of the past are still relevant. Here we look at the structure of diverse ‘grass’ mixtures recommended in the late 1800s and early 1900s.

Groups and species

Traditionally in Scotland, managed ‘grass’ (as distinct from rough grazing) was rarely just left as permanent, untended grazing land. It was either sown for hay or pasture over one, two or three years or left longer as ‘permanent’ grass, but even the latter was usually re-sown after a time to re-introduce species forced out by the more competitive grasses. Published in 1925, W M Findlay went into some detail on how grass mixtures were managed, but the specific interest is that he described mixtures in terms of the mass of seed of each component species [3].

 

Fig. 1 A seed mix made up of grass (blue-green) and legume (red): the inner circle showing all grass and all legumes; the outer circle showing two grass and two legume species.

The lists in Findlay are here presented as circular diagrams of the type illustrated in Fig. 1. The inner circle shows the percentage of seed from the grass family (blue – green) and the legume family (red). The outer circle shows the percentage seed of each species of grass or legume, individual species distinguished by different colours or shades.

In the example shown, the grass makes up about 80% and the legume 20%. There are two species of grass and two species of legume. This is a simple mixture but is still more diverse than many grass fields today.

Cattle on rolled hay field, Inverness-shire, 22 June 2019
Mixtures of increasing complexity

Four mixtures are shown in Fig. 2, the one top left is that from Fig. 1 but with species indicated. It is a mixture recommended for one year’s hay, after which it will be cultivated and turned to arable or transformed into another mix. The next three, moving clockwise, are mixtures of increasing complexity – top right is for two years’ grazing,  lower right for hay followed by grazing and the lower left for permanent grass.

The number of species increases in both grass and legume categories from top left clockwise. The permanent grass mix contains a third category – broadleaf or ‘dicot’ species that are not legumes (orange brown). Of the latter category, chicory and yarrow are included but not plantain which was commonly sown in ‘grass’ mixtures in the Improvements era.

Fig. 2 Four ‘grass’ seed mixes of increasing complexity from top left clockwise, intended for different purposes shown above each circle. Plant species and their proportions, based on sown seed mass, are indicated by different blue-green colours for grasses, red for legumes and orange-brown for broadleaf-but-not-legume plants. Original data in Findlay (1925)

In all categories, grass occupied about 80% (four fifths) of the mixture and legumes 20%, or a little less in permanent grass. The legumes include red clover (two forms), white clover (including a ‘wild’ version), alsike and kidney vetch. The permanent grass mix also has chicory and yarrow.

Findlay also gives an example (Fig. 3 here) of one of R H Elliot’s mixtures from his book Agricultural Changes (1898) which was later published as The Clifton Park System of Farming [5]. Notable in Elliot’s mix is the presence of legumes but also the much greater proportion of other broadleaf plants, most of which were included for specific functional properties [6]. Findlay does not agree wholeheartedly with Elliot’s recommendations, relating for example from his own trials that some of the broadleaf plants did not penetrate a hard soil pan, as Elliot suggested they would.

Fig. 3 Proportions of main groups and species in one of Elliot’s seed mixes [5] given in Findlay [4]: grasses, blue-green; legumes, red; other, orange yellow.

The proportion of seed in mixes was based on trials to assess how much seed of each was needed to cover an acre. Then seed mass was adjusted to suit the balance in the mixture, seed size and germinability and whether hay (flowering heads, less dense) or pasture (leaf, more dense) was the aim.

Were native plants used? Many of the grasses and legumes are native to Britain, but there was an international trade in seed then as now. Many varieties were imported for testing and usage. Over time, lays and pastures would have become a mix of native and imported populations.

The mixtures recommended by Findlay and those by Elliot are based on serious investigative studies that imply a sound knowledge of plants. They were devised at a time before mineral nitrogen fertiliser became cheaply available and among the primary aims of the mixtures was to increase the ‘health’ and fertility of soil as well as feed livestock.

Hay field recently cut & baled, Carse of Gowrie, 20 July 2019
The contribution of nitrogen fixing legumes

By the early 1800s, forage legumes had become standard in sown grass mixtures.  Writing well before Findlay and Elliot, H Stephens in The Book of the Farm [6], first published 1841,  gave weights of the grasses and legumes in mixtures designed for a range of purposes. (The author farmed in Angus for part of his life.) Stephens gives the seed weights for mixtures suited to various durations and conditions: he even includes all-legume mixes and his short-term lay contains about one-third legumes by seed weight.

In all these accounts, the main forage legumes were red clover Trifolium pratense in various forms and white clover T. repens. Others referred to by these authors, included in mixes for specified durations and soils, were alsike T. hybridum,  suckling clover T. minus and crimson clover T. incarnatum (the latter generally considered unsuitable for northern latitudes of Britain but will grow here) Other species were the medic or hop-trefoil Medicago lupulina, bird’s-foot trefoil Lotus corniculatus,  lucerne Medicago sativa and kidney vetch Anthyllis vulneraria.

These are by no means the only ones trialled in Scotland. There was clearly a thirst in the 1700s and 1800s to explore a wide range of species before settling on the clovers. In The Book of the Farm (1908 edition revised by MacDonald), they write about clovers:

” …. the most valuable herbage plants adapted to European agriculture – the white and red clovers. Notwithstanding what has been said of the superiority of lucerne, and of the excellence of sainfoin in forage and hay, the red clover for mowing and the white for pasturage, excel, and probably ever will, all other plants.”

Despite the uncertainty in how seed mass translated to plant mass, Findlay provides one of very few quantitative descriptions of the proportion of nitrogen-fixing legumes in a mix from the period shortly after WW1 when the scientific study and practice of agriculture was becoming established.

Clovers used in grass mixtures: (top left c’wise) red, white, crimson with white, crimson flower and alsike.
Mixtures were planned based on functional characteristics

The mixtures suggest there was a practical understanding of how species would interact when growing in a field. The author points to eight different properties that should be considered in choosing a mix.

  • Adapted to the local soil:  particularly to sandy or peaty soils.
  • Longevity: early or fast growth coupled to short life, e.g. red clover not expected to survive in permanent grass.
  • Habit of growth: a correct mix of ‘top’ plants that provide much of the fodder and ‘bottom’ plants that cover soil and ensure no gaps.
  • Time of year: a correct mix of developmental phases to ensure growing foliage is present for as long as possible.
  • Readily eaten by stock: (fairly obvious but) need to avoid plants that are less palatable or which become unpalatable with age.
  • Feeding quality: (again fairly obvious but) need by experience to assess quality depending on local conditions and manage so as not to diminish quality (and Findlay admits that quality was at that time difficult to measure).
  • Must die when ploughed: so as not to occur as weeds in subsequent crops (less important if permanent pasture is the aim).
What happened next?

One of the great uncertainties in defining agricultural trends is how the composition of grass mixtures changed since the annual census began over 100 years ago. Whereas, the areas sown with grains such as peas and beans were recorded [8], legumes in grass mixtures were not recorded. The census restricts managed grassland to the two main categories, short-term and ‘permanent’. For a time, the census also recorded the proportion of each used for hay or grazing.

There has been no consistent recording of the composition of grass, so the trajectory from the recommendations of the 1920s to the present is unknown. Yet travelling around the country, observing grass and crops, usually from the other side of the fence, leads to the conclusion that most current grass is far from diverse. In some fields there is one or two species, typically perennial ryegrass and timothy. Legumes except for the occasional white clover are absent. In the main, managed grass in Scotland has been de-diversified.

But not all of it …… [Further articles in this series will look at remaining sources of grassland diversity in low-input and organic farming and in commercial seed mixtures.]

 

 Sources, references, links

[1] Andrew Wight’s travels in the late 1700s describe first hand the improvements in field practice that commonly included sowing mixtures of grasses, legumes and other plants. Available online: Wight, A. 1778-1784. Present State of Husbandry in Scotland. Exracted from Reports made to the Commissioners of the Annexed Estates, and published by their authority. Edinburgh: William Creesh. Vols I-VI (e.g. search for title in Google Books).

[2] Recent EU research funding in agricultural and food systems is distinguished by the inclusion of a wide range of small enterprises that will be effective in rediversification. Agroecology at the James Hutton Institute (Dundee, UK) is leading several EU initiatives of this type including TRUE true-project.eu and Diversify plant-teams.eu.

[3] The Living Field project www.livingfield.co.uk at the James Hutton Institute promotes outreach and education. Its garden near Dundee displays many of the plants grown for food and feed, including most of those noted above.

[4] Findlay, W M. 1925. Grassland in Scotland. In ‘Farm Crops’ edited by W G R Paterson. The Gresham Publishing Company, London.

[5] Elliot RH. 1898. Agricultural Changes, later published as The Clifton Park System of Farming. Available online at journeytoforever.org.

[6] Stephens H. 1841. The Book of the Farm. Blackwood, Edinburgh. Printed in many subsequent editions in the later versions of which, revised and re-written, it was named Stephens’ Book of the Farm. Available online from various sources.

[7] Most plants in Fig. 2 and Fig. 3 are recognisable from the common names given by Findlay.  Burnet probably refers to fodder burnet, now given the botanical name Sanguisorba minor and recognised as subspecies muricata to distinguish it from salad burnet (subspecies minor).

[8] Trends in grain legumes and the benefits of increasing their presence in modern agriculture and food supply chains are examined by: Squire, Quesada, Begg & Iannetta. 2019. Transitions to a greater legumes inclusion in cropland ….. Food and Energy Security https://doi.org/10.1002/fes3.175 doi (available free online).

Author/contact: geoff.squire@outlook.com or geoff.squire@hutton.ac.uk.

Funding  The author currently has honorary (unfunded) status at the James Hutton Institute. A background knowledge of crop-grass mixtures was gained in past years through funding from the Scottish Government Strategic Research Programme and EU projects, mainly TRUE [2].

Resilience in a three-grain production system

Summary 

Cereal farming in the north Atlantic region improved to a point in the mid 1900s where starvation and famine were a distant memory. Half a century on from then, impending pressures through soil, climate and economics are threatening stable and reliable grain production. Yet the dire predictions of some commentators are unlikely to happen. Cereal farming has repeatedly adapted and survived since the first settlers brought grain to these islands.

This article summarises the changes that have occurred over the past century and suggests the system has in-built resilience through its combination of three grains – oat, barley and wheat. 

Cereal country, Scottish Borders, August during harvest (@curvedflatlands)Cropland in the northern part of the British Isles has grown barley, wheat and oat as its main cereal grains for thousands of years. Barley and wheat have been recorded since the neolithic, oats perhaps later. Cultivation of all three has sustained people and had been demonstrably sustainable, in that it continues.  There is no reason in principle why it should not continue well into the future.

Until the mid-1900s, these three home-grown grains were the main food of people and livestock. Other crops such as rye have occupied little area. However, at no time were the areas or proportions or uses of these crops fixed. Rather, they have changed as part of long term societal trends and over shorter time scales in response to international markets and bad-weather years.

In 1900, oats dominated. Then the next 100 years saw major changes in the proportional area of the three cereals (Fig. 1).

 

Fig. 1. The proportions of oats, barley and wheat in selected years of the annual agricultural census for Scotland [1, 2]. In 1990 and 2018 w and s refer to winter and spring barley.

It is sometimes assumed that the period of agricultural intensification following WWII, and operating mainly between 1960 and 1990, caused the greatest upheavals in the history of agriculture, but major change in crops and output occurred during the Improvements after 1700 and then in the later 1800s.

Winter wheat, ripening in late August (@curvedflatlands)
Change at the turn of the century – 1900

Figures taken from the official agricultural statistics from 1883 [1] show a steady decrease in the area grown with arable crops compensated by an increase in the area of ‘permanent’ pasture. The total land area grown with all crops and grass was more stable.

In just less than two decades before 1900, around 10% of the cereal area was lost to grass. Turnips and swedes – the winter lifeline for people and stock since the 1700s Improvements – had begun a steady descent that was to continue well into the next century, and the grain legumes – peas and beans – had even then become minor crops.

Fig. 2. Proportions of the three cereals in 1900 at a time when the area of grass was rising and arable (tilled) crops was falling. The area grown with cereals is shown under the pie diagram [1].

Symon labelled the period 1875-1914 ‘Forty bleak years’ [3],the bleakness caused as least as much by international trade pressures and inequalities in local society than anything biophysical. Yet he pointed to Scottish farming being ‘elastic’, enable to withstand the shocks of depression due to the three grains and the varied stockraising.

In and around 1900, oat occupied about three-quarters of the cereal area, barley around 10% and wheat the rest. The proportions of the three cereals changed little until after WWII. Economically, oats was less profitable than the other two but was hardier and easier to grow on the little nutrient resource available.

Spring barley, sown early, photographed 24 April, Angus coast (@curvedflatlands)
Intensification 1960 to 1990

The hard lessons of agricultural insufficiency in 1914, repeated in the 1940s, led to government-backed programmes for agricultural improvement, which also took advantage of new opportunities for international trade and technological advances [4]. Deeper cultivation allowed roots to explore an increasing volume of soil. Mineral nitrogen fertiliser became widely available and relatively inexpensive; and from the late 1970s chemical pesticides proliferated to control the many weeds and diseases that sought their share of the nitrogen! New cultivars were introduced with higher yield potential, mostly through a larger the grain ‘sink’, allowing a rising harvest index (grain/total mass).

Fig. 3. Proportions of area (pie diagrams) and total area (figures beneath) sown with oats, barley and wheat in 1945 and 1990. Barley in 1990 is separated into winter and spring varieties [1, 2].

The results of intensification were stunning. Cereal yields increased sharply from the 1960s. Most of the wheat was autumn sown, as was a proportion of the barley. Together these ‘winter’ crops came to occupy about 20% of the total cereal area. Compared to spring barley and oats, they were in full leaf at the time of peak solar income in late May, June and July. This shift in timing enabled them to accrue more photosynthetic mass to feed their higher grain ‘sink’.

Barley and wheat became more profitable as sources of alcohol and stockfeed. Oats – the only one of the three now used to feed people – declined to an area equivalent to that of wheat a century earlier. Most other cereal carbohydrate eaten by people is imported as bread, pasta, rice and maize.

Winter barley ready for harvest, late July, Borders (@curvedflatlands)

A quarter century of level output

During intensification, the area grown with cereals recommenced its pre-war decline (Fig. 3). By 1990, the cereal area was 90% of that in 1945.

But another and more significant change occurred. By the early 1990s, the rapid rise in yield due to intensification came to an end in the main cereal areas (for reasons that are not entirely clear). Yield increased a little over the next decade but then levelled. Despite many technological advances, total cereal output stabilised after 1990 except for fluctuations due to the advent of set aside and variable weather [3].

A similar pattern of levelling outputs has occurred in many parts of Europe and much farther afield. Is all now stagnation and decline?

Not quite. Recent records of yield and sown area suggest that while yield may be sensitive to bad weather years, such as the wet 2012 and dry 2018, farming has a capacity to shift land between the three cereals to offset the worst the weather can throw at it. Moreover, the yield per unit area of oats has increased to become close to that of spring barley [5].

Despite cereals giving poor economic returns at this time, the ‘system’ is not mired and should be still able to respond to the inevitable impending change.

Whole-crop oats, being cut 30 July, Orkney (@curvedflatlands)
External and internal pressures / capacity for adaptation

The cereal- and grass-based croplands of lowland Scotland face a set of internal and external pressures to which they must adapt. They include –

  • internal degradation of soil, element cycles and food webs due to intense cultivation, a factor likely to increase pressure on surrounding ecosystems but also to decrease the capacity of land to yield;
  • climatic change and extreme events of the type that dented output in 2012/3 and 2018;
  • continued reliance on external sources of nitrogen and phosphate fertiliser;
  •  further pressure on the economic  position for mass-market grain, for example, owing to competition from other countries and products.

One threat that should be no longer feared, however, is that of repeated crop failure, starvation and famine that hit parts of the country as recently as the mid-1800s. And there are increasing positives –

  • greater demand for home-grown cereal products, for example through an increased desire for local, sustainable food and drink;
  • technical innovations in cereal varieties and agronomy that open new higher-value markets.

 

Winter wheat ripening before harvest, late August, Borders (@curvedflatlands)

The line of census records since the early 1880s has shown massive shifts in the total and relative areas cultivated with the species and in the agronomic inputs to those areas. If farming has adapted in a certain way, then it should be able to repeat or reverse the change. Among options are –

  1. Broad scale shifts in the proportions of crops and grass, possibly reversing in part the shift towards grass (Fig. 3).
  2. Continued decrease in the area grown with cereals but concentrating on higher-value products or higher yield (i.e. by taking cereals off the less productive land, a trend already apparent).
  3. Altering the proportions of winter and spring varieties to manipulate the trade offs between yield, inputs and selling price.
  4. Replacement of high-input winter cereals with less demanding spring oats in response to challenging conditions (as happened in the 2012-2013 wet years).
  5. Growing more ‘mixed grain’ (two or more cereals in the one field) or cereal-legume mixtures such as mashlum, that need fewer agronomic inputs [6].
  6. Introducing grain legumes or grass-legume leys into crop systems to reduce reliance on mineral nitrogen and hence cut GHG emissions.
  7. And there are many others   ….

Now these might not seem like anything markedly out of the ordinary (when surveying the past 150 years) and indeed they are not. Yet cereal farming in many parts of the world would envy these possibilities: there are vast areas in some continents grown with only one main cereal that offers little scope to engineer change.

Moreover, the climate here, on the Atlantic seaboard, will probably not extend to real extremes due to its oceanicity. Complete crop failure caused by weather is still very unlikely here compared to places (for example) like New South Wales and Victoria in Australia where much of the cereal farming is already at risk without irrigation in a ‘normal’ year.

Ps. This article offers background to subsequent notes on this site that will examine the subtle and temporary shifts in the area of the three cereals that occurred in the ‘extreme’ weather years of 2012 and 2018, with consequences that lessened the overall yield ‘hit’ at harvest.

Cereal fields in stubble, Strathspey, January (@curvedflatlands)
Sources, references

[1] Agricultural Statistics 1912. Volume 1, Part 1. Acreage and livestock returns of Scotland, with a summary for the United Kingdom. Board of Agriculture for Scotland. Some data included for the census years back to 1883. And subsequent yearbooks in this series up to 1978.

[2] Economic Report on Scottish Agriculture: 1980 onwards. Scottish Government – links to all data at Agriculture and Fisheries -Publications.

[3] Symon JA. 1959. Scottish farming: past and present. Edinburgh, London: Oliver and Boyd.

[4] Squire GR. 2017. Defining sustainable limits before and after intensification in a maritime agricultural ecosystem. Ecosystem Health and Sustainability 3/8 (open access, available at https://doi.org/10.1080/20964129.2017.1368873

[5] Cereal and oilseed rape harvest: 2018 final estimates. Scottish Government. Published 12 December 2018. Downloads available from link.

[6] For references to cereal-legme mixtures: Living Field posts Mashlum  – a traditional mix of oats and beans and Mashlum no more! Not yet.

Author/contact: geoff.squire@hutton.ac.uk, geoff.squire@outlook.com

Funding  The author currently has honorary (unfunded) status at the James Hutton Institute. A background knowledge of crops, weather and climate was gained in past years through funding from the UK Overseas Development Administration and UK Department of the Environment while based at Nottingham University (1970s, 1980s) and more recently through the Scottish Government Strategic Research Programme.

Landscape mosaic defines pesticide loading

The latest Pesticide Use Survey for grass in Scotland presented by SASA [1] continues a line of meticulous reporting and analysis by the UK’s pesticide survey teams [2]. It allows the conclusions –

  • the 2017 survey, published 2018 [1], found 3% of permanent and temporary grass was treated with pesticide, most of which was chemical weedkiller (herbicide);
  • Scotland’s lowland farming areas comprise a mix of fields, some having  no pesticide treatment (temporary and permanent grass) and others having very high pesticide treatment (arable);
  • at the scale of the landscape, both the benefits and risks of pesticides depend on the proportions and spatial configurations of crops and grass;
  • data from the EU’s Integrated Administration and Control System (IACS) for farm payments are now being used by the Agroecolgy group at the James Hutton Institute, Dundee, to estimate pesticide pressure in landscape mosaics.

This note summarises the latests SASA data, gives examples of landscape mosaics in east Scotland and argues that ‘low pesticide’ does not always imply ‘high biodiversity’.

Sheep feeding on hay, winter on the lower Sidlaw hills

Three broad categories of grass are considered in census records – permanent or long-term grass, temporary or rotational grass and rough grazing [3]. Permanent and temporary grass are both managed to support commercial grazing and offtake of hay or silage for feed [4]. Only 3% of these categories of grass was treated with pesticide in 2017 [1]. Rough grazing covers much of the higher land, is largely unfertilised and less than 0.5% of its total area was treated with pesticide [5].

Most of the pesticide applied to the 3% of permanent and temporary grass is chemical weedkiller (or herbicide). Those fields treated typically receive one herbicide formulation in a year. The three most widely used herbicides were MCPA, Fluroxypyr and Fluroxypyr/triclopyr, mainly for control of broadleaf weeds such as docks and thistles [1, 6]. Other herbicides such as glyphosate were applied over a much smaller area. The largest area treated with any formulation was the estimated 11,400 ha receiving MCPA. In total, 25 different herbicide formulations were recorded as being applied to grass in 2017, but all except the three cited above were applied to very small areas [1, Table 5 in report].

View of mixed arable-grass landscape in the north-east region

No treatment of fungal disease? In arable crops, fungicides tend to dominate pesticide usage. Yet very little of the area of grass was treated for fungal pathogens. Fungicide treatments to grass have even decreased compared to the survey in 2009 [1]. The very small area treated with herbicide and the almost negligible use of fungicide imply that most managed grass here gets no pesticide.

Questions now arise as to whether spatial groupings of grass fields create low- or zero-pesticide landscapes and whether the presence of grass among arable fields moderates the much higher pesticide applications to cereals, vegetables and potato. To resolve these questions, it is necessary to know the spatial variation in grass and arable land across the country and locally.

Distribution of permanent grass, temporary grass and arable

The categories of permanent and temporary grass co-occur with arable or ploughed land mainly in the east, but also across the central belt and to the west. Permanent grass is left without being ploughed for many years. Temporary or ‘rotational’ grass is sown, cultivated for a few years and then ploughed and sown with arable crops for a few years. The cycle is usually repeated.

The total area of crops and grass was 1,910,347 ha in the 2017 census [3], of which 31% was arable and 69% grass, but the mix of crops and grass is far from uniform from west to east (Fig. 1, bar chart).

Fig. 1 Areas occupied by crops, grass under 5 years old (grass <5) and grass 5 years old and over(grass 5(+)) in the four regions shown right with simplified boundaries. Source: Economic Report for Scottish Agriculture 2016 and data for 2017 [3].

The north-west (NW) region has, despite its large area, the least of these three categories of land. The south-west (SW) and south-east (SE) have similar total areas of crops and grass, but the south-west (SW) has very much more permanent grass (grass 5 years and over) than the SE. The NE has similar proportions of grass and arable to the SE. The regions are indicated very approximately on the map in Fig. 1 – the actual boundaries between regions follow administrative units and can be viewed online in the Economic Report for Scottish Agriculture [3].

The varying balance of grass and arable in Fig. 1 is caused mainly by climatic differences between the wetter west (more grass) and the drier east (more arable). Most pesticides are used in the east because the climate there is dry enough for commercial growing of cereals, tubers and oilseeds.

Arable-grass landscape mosaics

Starting around the year 2000, it has been possible to map the configurations of crops and grass in the landscape using data from the EU’s Integrated Administration and Control System or IACS. A previous article on this site explains the method [8].

Results to date show that patches of land in the SE and NE regions  are rarely all-arable or all-grass, but the proportions of arable and grass can differ widely between localities. Two representative landscapes are compared below (Fig. 2) as circles extracted from the much larger surrounding land mass. Each small shape within a circle is an agricultural field or a stretch of woodland. The average size of fields across the country as a whole is 7 ha, but fields under mainly arable cultivation tend to be larger than fields under grass.

 

Fig. 2 Contrasting eastern landscapes (showing differing proportions of grass (light green) and cereals (red, orange). Other colours: dark green, woodland; yellow and blue, arable but not cereal. The average field size in the country is about 7 ha.

The next step is to assign a pesticide application to each of the fields. Pesticide surveys are based on a sample of farms, then upscaled using the proportions of crops and grass in different zones around the country [1]. It is not possible therefore to assign either a total pesticide usage or an application of specific formulations to individual fields.

For the purpose of risk-benefit analysis, the likely or potential pesticide usage  in fields can be assigned from a national or regional average based on fields sampled in the survey. These averages, which we usually call ‘nominal’ values offer a reliable first estimate of the degree to which landscape mosaics differ in pesticide applications. As described in Mapping pesticide loading spring cereals are typically treated with around 5 formulations, winter cereals around 10 and potato more than 20.

The landscape to the left in Fig. 2 is mostly grass (light shades of green) but with a few clusters of cereal fields (red, orange). Most fields will therefore not be treated but the red and orange fields will be treated with herbicides, fungicides and some insecticides.

The one on the right is mostly arable, again the cereals shown in red and orange. However, even in the densest arable areas, there is some grass that will not be treated with pesticide.  There are also clusters of all-arable fields, each of which will get treated with between typically 5  and 20+  pesticide formulations annually depending on the crop. The formulations applied will differ between the crop-types.  Therefore the red-orange-yellow clusters will be treated each year with a very wide range of active substances.  (Details can be found in the Arable Crops surveys by SASA at the link given in [1].)

View of mixed arable-grass landscape in the south-east region
Management at the landscape scale – no easy solutions

As described in a related article Mapping pesticide loading, the IACS data can be used to define potential hot-spots of pesticide application in relation to defined ecological risks or the presence of non-target organisms such as wild plants and insects. Configurations of the type shown in Fig. 2 are also needed to develop advice on management of the landscape, for example in preparing ‘area-wide integrated pest management (IPM)’ or restoring biodiversity and its many positive functions. (More on this in a later article.)

However, simply manipulating pesticide treatment by altering the proportions of crops and grass at the scales in Fig. 2 will not by itself lead to enhanced or more stable farmland biodiversity. The main reason is that grass fields have come to support a different and generally lower plant biodiversity than the most diverse cropped fields. Disturbed cropland subject to ‘rotation’ or sequences of different crops has the capacity to hold a buried soil seedbank of up to 40 or 50 mainly uncompetitive broadleaf plant species, which if allowed to germinate and grow support much of the invertebrate food web in agriculture. In contrast, permanent grass has a different composition, both of its visible plant species and its seedbank.

A major obstacle to progress is that little is known of the species-composition of managed grass in the lowlands. It has not been a priority for research funding in recent decades. One thing is certain, however – most grassland today is very much less diverse than it was in the 1800s and early 1900s. Notably, legumes such as clovers and vetches have almost disappeared from managed grass, as have broadleaf (dicot) species. This unheralded decline is yet another major, long-term shift in the biodiversity of agricultural land and will be explored in the next article in this series.

Acknowledgement and credits

Contact: Geoff Squire geoff.squire@outlook.com / geoff.squire@hutton.ac.uk.

IACS analysis and geospatial mapping – Nora Quesada nora.quesada.pizarro@hutton.ac.uk and Graham Begg graham.begg@hutton.ac.uk.

Scottish Government provided funding to the James Hutton Institute to carry out the analysis of IACS data used in Fig. 2.

Sources, references, links

[1] Pesticide Usage in Scotland. Grassland and Fodder Crops 2017. By Monie C, Reay G, Wardlaw J, Hughes J. Science and Advice for Scottish Agriculture 0SASA) Edinburgh, at http://www.sasa.gov.uk/pesticides/pesticide-usage/pesticide-usage-survey-reports. Usage reports are compiled for chemical pesticides applied to crops and grass, not to livestock. See [9] for guidelines on sheep dip and other sources of pollution from animal husbandry.

[2] For Pesticide use surveys across the UK as a whole see Fera Science Limited: https://secure.fera.defra.gov.uk/pusstats/surveys/index.cfm.

[3] The latest agricultural census (2017) is summarised in the form of spreadsheets and graphs at Economic Report for Scottish Agriculture at https://www2.gov.scot/Topics/Statistics/Browse/Agriculture-Fisheries/PubEconomicReport. The full regional map is given online in the 2016 Report at https://www.gov.scot/publications/economic-report-scottish-agriculture-2016/ then navigate to ‘Geography and structure’.

[4] The designations permanent and temporary grass have changed at various times since the late 1800s. In the current statistics released by Scottish Government [3], the grass designations are ‘grass five years old and over’ and ‘grass under 5 years old’. Additional categories of ‘direct sown’ and ‘undersown’ grass, each occupying small areas, are recorded in the SASA pesticide survey.

[5] Land classed as Rough grazing in Scotland occupied 3,718,795 ha in the 2017 agricultural census which is 66% of the Utilisable Agricultural Area [see 6]. Of this total less than 0.5%, or about 14,000 ha, was treated with pesticide (sources in [1] above) including Asulam [6] used mainly to control bracken (granted as an emergency measure).

[6] For information on herbicides, e.g. MCPA http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/427.htm and Asulam http://sitem.herts.ac.uk/aeru/ppdb/en/Reports/1551.htm.

[7] Most of the fungicide applied to grassland in the 2017 survey was on ‘undersown’ grass, which is usually the name given to grass sown so as to emerge and grow underneath a nurse crop such as a cereal. About 48% of undersown grass was treated and even here it was ‘for the control and prevention of disease on the nurse crop [1, page 11]’.

[8] Integrated Administration and Control System, IACS: data became available from the EU’s IACS system from around 2000. The use of IACS data is described at Mapping pesticide loading.

[9] For information on sheep dip and other potential environmental hazards from livestock farming: see the SEPA (Scottish Environment Protection Agency) web pages at https://www.sepa.org.uk/regulations/land/agriculture/sector-specific-issues.

How.. next.. for Agroecology at Hutton

The profile of Agroecology at The James Hutton Institute has evolved over the last two decades. The group has weathered repeated challenges since its millennial beginnings, but faces real threats in the uncertain relation between the UK and the EU. 

This note examines the changing sources of funding available to the Group.

Agroecology?

The word has several meanings in current usage. Agroecology at the James Hutton Institute brings a highly quantitative approach, combining experimentation, statistics and modelling, to understanding state and change in managed ecosystems [1]. It is ‘systems’ science at scales from the plant to the landscape. More widely, agroecology has come to mean forms of agricultural production that tend to balance the stores and fluxes of energy and matter between human needs and the long term future of the ecosystem.

The two meanings are not incompatible. Agroecological studies at the Hutton clearly point to a future in which ‘scorched earth’ strategies have no place. But to get to that conclusion and to design sustainable systems, we work on a range of approaches to ecosystem management that includes those reliant on severe and frequent disturbance and high inputs of pesticide, fertiliser and fuel.

Two decades of competitive funding

The funding of land-based research in Scotland has had the advantage of consistent support from Scottish government through funding to Scottish institutes, both before and after devolution. This support has enabled research groups to establish a base from which they can seek additional finance from other sources through what is commonly called ‘competitive funding’.

Fig. 1. Sequence of main competitive grants to Agroecology from 1998 to 2018: orange-red, UK sources, mainly government departments and some research council; blue, EU sources; green, joint industry-government initiatives. EU 1, EU 1* and EU 2 are explained in the text. The grey downward arrow is ‘now’.

The sequence of competitive grants awarded to Agroecology at the institute is shown in Fig. 1. Most are for 3-4 years, except a few one-year projects that tend to be exploratory. The 3-4 year grants each typically bring a few hundred thousand £ sterling to the Institute, enough to pay salaries of research leaders and technical staff. Many other grants, bringing <£50k, are not shown.

The challenges to be faced are clear. For the first ten years, the group was sustained on competitive funding awarded from sources within UK government departments and research councils. Those sources dried up unexpectedly in 2006-2007, and the group had to change tack or go out of business. New sources were found, mainly in the EU (blue bars) but also through new applied funding from industry-government initiatives (green bars) such as Innovate UK.

In 2017, Agroecology achieved unrivalled success for a small research group in securing three major, multi-partner EU grants, two of which it coordinates.  And the UK intends to leave the EU in 2019. How next!

[Read on for a short history of the first 20 years.]

UK sources of competitive funding

The Scottish coordinated programme in Vegetation Dynamics funded from 1995 provided a foundation. The first competitive grant was secured in 1998, for one year. There followed a succession of projects from UK sources, coloured orange-red on Fig. 1, mainly departments of the environment, agriculture and food (DETR, Defra, MAFF, etc.) but also research councils (NERC, BBSRC) when it was possible to team with eligible institutes from England and Wales. A couple of Scottish competitive grants are in there but not distinguished.

Topics of research included environmental risk assessment, population dynamics, gene movement in the landscape and optimal management of production systems.  These UK sources presented excellent opportunities to expand. Coupled with the Scottish base funding, they allowed appointment of research and technical staff [2].

The UK sources petered out in 2005-2006 – for various reasons, including changed priorities in UK ministries and an increasing difficulty for Scottish Institutes to gain access to UK competitive schemes. The period 2007-2009 was a low point. If the axe of external review had fallen at that time …… there would be ‘Agroecology no more’.

EU became the major source of funding from 2010

The value of European funding and collaborations became clear during the one EU (blue) grant gained among the sequence of UK grants. It was a taster of the enormous advantage that could be realised by collaborating with many partners across Europe’s diverse cultures and agroclimatic zones.

Following a major redirection of effort, the Group then secured a sequence of EU grants, each for four years (blue bars on Fig. 1), that kept the infrastructure in place and allowed development of new methods and new ideas [3]. Above all, the money enabled us to form major consortia with capability across Atlantic, Boreal, Continental, and Mediterranean climatic zones (Fig. 2), latterly extending to the Balkan.

In parallel with the attention to EU opportunities, the group also returned a series of  grants, coloured green in Fig. 1, funded jointly by government and industry in various schemes (such as Innovate UK). Generally, this ‘industrial’ funding could be aligned with the EU funding and gave a lead into new commercial areas that were to be exploited in the future.

Fig. 2. Map of Europe (European Space Agency -ESA) on which climatic zones are approximated. Arrows lead to and from Agroecology’s base,  the Atlantic maritime hub.

The EU projects were the major consistent source of money that allowed progression. Those grants labelled EU 1 on Fig. 1, with or without a *, were substantial projects in which Agroecology staff worked on the Project Management Group and led major workpackages. Those 4 marked EU 1*, were instrumental in alowing us to establish European networks in topics such as gene movement and persistence, legumes and nitrogen fixation, integrated pest management and environmental risk assessment [3].

Then in 2017, the commitment escalated

So far, members of the team had led multi-partner workpackages and served on programme management groups, but other organisations such as INRA (France) had coordinated the projects.

This changed in 2017 after running two successful bids and then coordinating two whole projects.  This was a major achievement by colleagues, especially given the small size of the group and its existing over-commitment to other work. These two large, multi-partner projects, labelled EU 2 on Fig. 1, signalled a new phase in Agroecology’s evolution [4].

They and the other existing EU project won at the same time will continue until 2020. The sheer degree of networking and organisation across Europe has risen above expectation – we are now collaborating with probably over 100 organisations – research institutes, universities and small businesses.

How next?

The degree of drive and ambition evident among colleagues  prompts the question ‘how’ not ‘what’. That the subject will continue to succeed by the efforts of such people is not in doubt.

The question of ‘how’ rests in the opportunities for funding. The EU was hard to get into for a first grant: the competition was and remains fierce. Very high standards had to be maintained when bids were led by others. Now even higher standards are expected for coordination.

The three current EU grants continue until well after the date at which the UK presently expects to withdraw from the EU: continued funding to the end of these grants has been guaranteed we believe. Colleagues are active as coordinators or partners is still more bids. Yet despite the great uncertainty over withdrawal from the EU, there is no option but to continue this emphasis in Europe …. yet at the same time to seek out additional opportunities more widely.

Continued …

There are many questions to be argued over whether small research groups should spend so much effort on bidding for new funding above what the base provides.

What does the money do? First, in our case, it provides people with work, wages, opportunity for improvement, scientific contacts in other countries, and visiting students and researchers. It enriches their scientific experience immensely.

Second, it magnifies our field and lab (but mainly field) experience by allowing us to operate consistently across many sites over several agroclimatic zones. The north-east Atlantic maritime lands in which we are based are themselves diverse, yet conclusions reached across all regions from the Boreal to the Mediterranean and Balkan have unassailable weight.

Further pages on this topic to follow –

Origins of Agroecology in the Scottish coordinated programme of the mid 1990s

What is best – hone your skills to bid competitively with all the effort that takes or lie content with base funding?

Notes

[1] The Agroecology Group became so named somewhere between 2000 and 2005 in accord with the collective wishes of its members. Its name was retained when in 2011 the Scottish Crop Research Institute became part of The James Hutton Institute. That change had no effect on the progression of funding in Fig. 1.

[2] Names of project leaders are omitted from this post because the effort depended on all staff. The first phase of funding allowed the appointment of all current senior researchers and most long-term field and lab technicians. Several colleagues who made important  contributions have now moved on, or sideways to remain in the Institute. Further details of people involved can be found on the Hutton’s Agroecology group pages and through the links below.

[3] The EU grants up to 2016 and main investigators are described briefly on these pages at The contribution of European funding.

[4] The three EU grants that began in 2017 are TRUE on legumes, DIVERSify on mixed cropping – both of which are coordinated by Agroecology – and Tomres. The links lead to respective project web sites. [Personal note – my role in EU projects more or less ended in 2016: though it was good to watch from a comfortable distance the efforts to bid for the three successful  2017 starts.]

 

 

 

 

 

Mapping pesticide loading

The detailed records of pesticide usage compiled by SASA, or Science and Advice for Scottish Agriculture [1] have been used for many years and to various ends by the Agroecology group at the James Hutton Institute. Recently the group began using the records to map the likely loading of pesticide at different scales and in relation to various features of the landscape.

The data on pesticide are collected as part of regular government survey. SASA asks a sample of farmers across the region to provide detailed returns of the crop-protectant chemicals they use on specified types of crop and grass – such as winter wheat, spring barley, potato, oilseed rape,  rotational grass and permanent grass. The active substances and the number of times they are sprayed onto fields are collated and summarised in reports, every two years for arable crops and every four years for grass.

Fig. 1. Birse’s 1971 map of agroclimatic zones in Scotland (property of The James Hutton Institute).

Productive agricultural land lies in oceanic climatic zones, mainly around the east coast – generally within the red and yellow zones shown on Birse’s 1971 map in Fig. 1 [2].

The latest survey for grass published earlier this year confirms the results of the previous survey that most managed grass grass receives very low pesticide inputs. Typically, 3% of rotational and permanent grass is treated in any year, mainly to control broadleaf weeds. Contrast this with the yearly 10 pesticide formulations applied to winter wheat and 20+ to potato.

Over much of the lowlands, crops and grass are grown together in the same landscape, thereby creating a highly variable mosaic of pesticide loading. Combining SASA’s surveys with data on the crops or grass grown in each field enables construction of a map of ‘nominal’ pesticide application based on the assumption that each farmer applies the national average pesticide for each type of crop or grass.

Fig. 2. Maps of (left) relative number of pesticide applications for each registered field (dark brown high, yellow low) and (right) an example of the data being used to illustrate spatial aggregation, in this instance the mean pesticide in 10 km grid squares (maps by N Quesada, GS Begg and GR Squire, James Hutton Institute).

The map based on individual registered fields in the east between the Moray Firth and the Borders is shown on the left side of Fig. 2. Dark brown indicates high pesticide applications (9 or more formulations per year) and light yellow 0 to 2 applications. Agricultural land in much of the rest of the country (including the uncoloured areas in Fig. 2) is classed as ‘rough grazing’ of which less than 0.5% gets any crop-protectant pesticide.

The map to the right, covering most of the country, shows how the field-by-field data can be aggregated in various ways, in this case to show average loadings in 10 km squares.

A short article describing the method was published 30 November 2018 on the James Hutton Institute’s Linking Environment and Farming LEAF web pages an extended version of which will be available on this site.