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.


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 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. 


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; Squire, Quesada, Begg, Iannetta, 2019. Transitions to a greater legume inclusion in cropland …. Food and Energy Security (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,

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.