Diversifying the UK Agrifood System: A Role for Underutilised Crops

1. A Vulnerable Global Food System

The global food system is increasingly vulnerable to external shocks and to the existential threat of climate change. The UK imports nearly half of its food and, therefore, the food security and health of its citizens is vulnerable to external shocks and the impacts of climate change both at home and from where it imports its food.

1.1. The Globalised Agrifood System Is Failing

Supply chain disruptions, a pandemic, and now a war in Ukraine have exposed existing faultlines in a globalised food system that depends on a few staple crops grown in a few exporting regions and transported to countries that cannot otherwise feed themselves. Together, Russia and Ukraine supply 28 per cent of globally traded wheat, 29 per cent of barley, 15 per cent of maize and 75 per cent of the sunflower seeds that account for 11.5 per cent of the vegetable oil market [1,2]. Russia is also the world’s biggest exporter of nitrogen fertiliser, the second of potash and third of phosphorus and a major source of the fossil fuels on which global agriculture depends [3]. Just three `staple’ food crops (wheat, rice and maize) now provide over 60 per cent of the calories in human diets [4]. Not only do they sustain us, but staple crops also feed our livestock and, increasingly, our engines. We use 10 per cent of our three major crops and 18 per cent of vegetable oils for biofuels — equivalent to the food needs of 1.9 billion people. In 2021 China imported 28 million tonnes of maize to feed pigs and over 40 per cent of the wheat grown in the EU and 33 per cent in the US was fed to cows [5]. Our dependence on so few mainstream crops for food, feed and fuel will become an increasingly risky proposition in an uncertain and more crowded world. If we are struggling to feed a global population of nearly 8 billion people, how can we nourish a predicted 10 billion by 2050 on a hotter planet? To date, our response has been “business-as-usual” as importing countries scramble to find alternative sources of mainstream crops to those previously imported from Ukraine and Russia. However, to protect their food security, 23 countries, including India, have imposed restrictions on wheat exports and other foodstuffs.

The climate crisis remains an existential threat to humanity, our food systems, and the natural ecosystems on which we all depend. Agriculture is both a contributor to the climate crisis and its victim. It is responsible for between 21 and 37 per cent of global carbon emissions and, at the same time, the productivity and yields of mainstream crops are increasingly affected by extreme weather events caused by climate change [6]. In 2022, more than 40 per cent of wheat on North America’s Great Plains suffered from drought whilst floods in China meant that national wheat yields were amongst the poorest on record [7]. In May 2022 India registered record temperatures of 49°C and much of Europe suffered a deadly heatwave with sharp decreases across the continent in the yields of major crops due to heat and drought.

1.2. UK Food and Health Are Vulnerable

The UK depends on imports for its food security and is therefore vulnerable to the impacts of climate change in those countries from which it imports food. Three crops, (wheat, barley, and oilseed rape), account for 75 per cent of the UK’s 4.5 million hectares of arable cropped land whilst around half of the food consumed in the UK is imported. The UK’s top eight trading partners are all EU member states; in 2020, nearly 40 per cent of UK food imports by value came from just four EU countries (the Netherlands, Ireland, Germany, and France) [8]. Whilst 93 per cent of domestic consumption of fresh vegetables was fulfilled by domestic and European production, only 16 per cent of the UK’s fruit supply is grown locally (similar to the level in the 1990s) whilst the rest comes from the EU, Africa, and the Americas. Not only is the UK food system dependent on the climate and political stability of other parts of the world, it is also vulnerable to the impacts of climate change on food production at home. Under a medium emissions scenario climate change could reduce the proportion of `best and most versatile’ arable farmland from 38.1 per cent of agricultural land on a 1961 to 1990 baseline to 11.4 per cent by 2050 [9]. Under a high emissions scenario it could be further reduced to 9.2 per cent of agricultural land. The UK government is committed to a 'net zero target' of reducing its greenhouse gas emissions by 100 per cent from 1990 levels by 2050 [10]. Meeting Net Zero, whilst achieving other climate and biodiversity goals as well as the United Nations Agenda for Sustainable Development, will further add to pressures on land use for multiple and competing purposes beyond food production, for example to mitigate carbon emissions through the planting of biomass and energy crops. As well as risks associated with higher temperatures on yield and quality of mainstream crops, climate change has impacts on rainfall amounts and distribution, the availability of water for irrigation and increased frequency of drought and flooding.

The UK’s exit from the European Union brings with it additional complications in terms of costs and barriers to trade and the availability of seasonal agriculture workers from EU countries. Changes in UK agricultural policy include the replacement of direct payments to farmers with new schemes that reward farmers for delivering public goods that enhance the environment, improve animal welfare, or reduce carbon emissions. Since its exit from the EU, the UK has been in an “Agricultural Transition Period” during which the Government has maintained agricultural subsidies at the same levels as under the EU Common Agricultural Policy. However, it is now changing the payment system to provide “public money for public goods”. Under the new Environmental Land Management scheme (ELMs) [11], farmers will no longer receive payments for crop production or land tenure but for activities that contribute to public goods such as nature restoration, woodland management, flood prevention, soil improvement, animal welfare and carbon sequestration. Currently high energy costs are also having adverse impacts on other sectors of the food supply chain such as fuel, transport, labour, pesticides, fertilisers, and maintenance of protected environments such as glasshouses. Despite advances in breeding and agronomy, on-farm yields of crops including wheat and oilseed rape have not shown consistent yield increases since the 1990s [12].

Health inequality in England is increasing. Men in the most affluent parts of the country can expect to live for 9.5 years longer than their counterparts in the poorest areas [13]. For healthy life expectancy there is an even greater disparity between rich and poor with a gap of 19 years [14]. Women in the poorest areas now die younger than in 2010 and female Healthy Life Expectancy in 2017 to 2019 was almost five months shorter than in 2014 to 2016 and is now the lowest it has been since records began in 2009 to 2011 [15]. There is increasing evidence that our modern diet disproportionately affects the poor. Globally, nine of the top fifteen risk factors for morbidity, including high body mass index (BMI), high blood pressure, cardiac disease, diabetes and malnutrition, are associated with poor diets [16]. In 2017, the UK had the tenth highest adult obesity levels amongst the 38 member states in Organisation for Economic Co-operation and Development (OECD) and obesity has increased by 92 per cent since the 1990s [17]. In 2018, 63 per cent of adults in England were overweight or obese. Whilst the national average for obesity was 28 per cent, those living in the poorest areas had obesity levels of 36 per cent compared to 20 per cent in the less deprived areas [18]. The impacts of poor diet on health start young. Children living in the poorest areas of the country are four times more likely than those in affluent areas to be severely obese when they arrive at primary school and are five times more likely to be severely obese when they leave it [19]. Sixteen per cent of people in the lowest income group suffer from diabetes: more than twice the percentage of those in the highest income group [20].

The link between food, health, climate change and the agrifood system is irrefutable. Food is responsible for around one quarter of the UK’s carbon footprint, predominately from intensive fertiliser use, livestock production and food waste [21]. Poor diets contribute to one in seven deaths in the UK [18] and the dietary recommendation to eat a diverse diet containing a wide range of plant-based foods links directly to the limited number of plant species that are consumed in a typical UK household diet [22]. Our eating habits have changed over recent decades. The UK Family Food Datasets show trends in the purchases of food and drink by UK households since the 1970s [23]. These indicate increases in purchases of fresh fruit that are not generally grown in the UK, such as melons, grapes, and stone fruit as well as vegetables such as marrow, courgettes, aubergine, and pumpkin and decreases in the purchases of traditional fruits such as apples, and vegetables such as potatoes, cabbages, brussels sprouts, carrots, turnips, and swedes. However, like obesity and life expectancy, fruit and vegetable consumption also follows a social gradient, with adults and children in the lowest income decile eating, on average, 42 per cent less fruit and vegetables than recommended levels [24]. Whilst overall bread consumption has declined, purchases of oat and oatmeal products, and imported ingredients such as rice and fresh and dried pasta have increased.

Crop diversification is not a new concept in the UK and Defra’s Farm Business Survey 2016/17 claims that 66 per cent of farmers were planning to diversify their business within three years. However, a closer look reveals that `diversification’ is considered as a business term, where farmers are often encouraged to utilise their assets (machinery, building and land) for other purposes whilst diversification of crops and cropping systems is not explicitly included as a viable option to improve income. This is perhaps because underutilised crops are not popular among commercial growers owing to the risks involved with their adoption, established seed systems and guaranteed markets. Crop diversification is also considered a slow process in a risk averse industry that is increasingly threatened by the impacts of changes in markets and climates. According to statistics from the UK government [25], although the production of cereal crops increased by 5.7 per cent in 2021, the Farm Business Income (FBI) varied greatly among farmers and 16 per cent of farmers failed to reach a positive FBI. Continuous impact on production costs is expected in the future due to a multitude of factors such as Brexit, the COVID-19 global pandemic and recession, changes in food policies, and changes in the environment [26].

Current agricultural practices are based on the intensive production of high yielding crop varieties using the best arable land. To date, no specific plan has been proposed to harness the potential of diverse crops in less intensive production systems and on land that is less suited to mainstream agriculture. The absence of such a plan illustrates the dearth of detailed discussions on the potential of agrobiodiversity i.e. the variety and variability of animals, plants and micro-organisms that are used directly or indirectly for food [27]. For UK agriculture, any such discussions need evidence-based recommendations that are designed to diversify both production systems and income streams [28] as well as improve food and nutrition security.

2. UK RESPONSES TO THE FOOD CRISIS

The UK food system must change if it is to meet its climate and biodiversity goals and have a healthy and active population. For this, it needs a national food strategy and an innovation landscape in which, technical innovations, research and development and policy measures combine to unlock opportunities that go beyond business-as-usual on mainstream crops.

2.1. National Food Strategy

In June 2019, the UK government commissioned Henry Dimbleby to conduct an independent review to help develop its first National Food Strategy for 75 years [29]. The purpose of the review was to address the environmental and health problems caused by the UK’s food system, to ensure the security of the UK’s food supply, and to maximise the benefits of changes in agricultural technology. Whilst the scope of the National Food Strategy is limited to England, its terms of reference include relationships with the devolved administrations in Scotland, Wales and Northern Ireland as well as the EU and other trading partners. The National Food Strategy is designed to ensure that the UK food system delivers safe, healthy, affordable food, regardless of the location or income of individual citizens. To achieve these objectives, it makes 14 recommendations (Table 1) grouped into four themes that are designed to be implemented over a period of three years as part of a longer-term transition.

The National Food Strategy also recommends the creation of a Rural Land Use Framework and National Rural Land Map to encourage diverse methods of land management by setting out those areas best suited to three different types of landscape viz. high yielding farmland (for food production), low yielding farmland (farmed regeneratively) and semi-natural land (managed for nature). The framework should underpin the payments and regulations to incentivise farmers to achieve biodiversity, climate and food targets, and the metrics employed to monitor progress. The National Food Strategy also proposes a new “Challenge Fund” to help consumers change their eating habits and boost locally led initiatives to improve diet and health. Defra (Department for Environment, Food and Rural Affairs) has also launched its own Agriculture Transition Plan which includes funding for “farmer-led” innovation. The National Food Strategy calls for this funding to support a range of methods to reduce carbon emissions and improve the natural environment including investment in methane reduction technologies, such as feed additives for sheep and cattle, agroecological methods of farming and investments in fruit and vegetable production. Finally, the National Food Strategy calls for a Good Food Bill that would establish and periodically update a healthy and sustainable Reference Diet, to be used by all public bodies in food-related policy making and procurement. One objective of the Good Food Bill would be to define a statutory target to improve diet-related health.

2.2. Foresight Review

In 2021, Defra commissioned a Foresight Review to `inform agri-food Innovation Development and Realisation’ (Defra Project BD5013 – unpublished). The review aims to improve understanding of the innovation landscape, potential innovations, and the research, development, and policy measures to prepare the UK for future agri-food scenarios and unlock opportunities. It was also designed to advise how Government, industry and wider society can meet the ambitions of the National Food Strategy, 25 Year Environment Plan and Net Zero targets, and support agri-food research and development and innovation funding decisions. The review team used futures techniques (forecasting, back-casting, anticipatory thinking, simulations, and scenarios) and land use modelling, to characterise five future scenarios, spanning future climatic, socio-economic and political conditions. A literature review and engagement with agri-food stakeholders helped define the innovation investment landscape and allowed a systems approach in understanding potential future innovations and risks and opportunities over intermediate and long-term horizons. Eighty innovations were grouped into seven "innovation themes" expected to have the greatest potential impact towards achieving policy goals across the future scenarios. These themes were grouped into two categories: those that advance existing systems (such as genetic technologies and circular economy); and those that represent a systemic shift (vertical agriculture and protein transition) and may rely on the system advancement themes. Innovation themes allowed examination of innovation from farm to fork, rather than focusing on individual technologies. The review concluded that there is no `silver bullet’ solution and that the future needs of the food system are diverse, and innovations are interdependent and interrelated and proposes a range of interventions and innovations to achieve efficiencies in agri-food systems, reduce environmental impacts, adapt to climate change, and provide health benefits and food security. It sets out plausible pathways to achieve the 2050 ambitions through seven innovation themes:

• Vertical agriculture: Crops grown in vertical layers and technologies, such as LED lighting, hydroponics and aquaponics, to produce food efficiently with limited land
• Protein transition: Includes cellular agriculture (lab-grown alternatives), novel vegan products, insect-based products and classic vegan and vegetarian products
• Genetic technologies: A group of technologies that make changes to an organism’s DNA by moving, adding, or deleting genetic material
• Input efficiency: Organic fertilisers and pesticides, nanotechnologies and precision input technologies, feed additives and micro-irrigation
• Precision agriculture: Group of connectivity technologies, including on-farm data collection, value-added analysis, smart machinery and equipment (including robotics and automation) and marketplaces and supply chain logistics
• Circular economy: Business model that embraces technical and social innovations that can reduce waste across the supply chain and consumer use, including waste
• Regenerative agriculture: System of farming practices that enhance natural capital and protect ecosystems, supported by an array of technologies.

The Foresight Review drew upon literature reviews and scenario modelling interviews with developers, researchers, users, and policy experts across the agri-food sector. A framework was developed to identify high-priority innovations which were modelled for a range of plausible futures. The results of the literature review and modelling outputs were the subject of a workshop with over 60 food innovation experts.

3. AGRICULTURAL BIODIVERSITY

Underutilised crops can help transform global and UK food systems into ones that are climate-resilient, nutritious, and healthier for humanity and the planet. Harnessing the potential of underutilised crops requires collective actions, and an evidence-base that spans the value chain from genetics through to markets as well as political will and investment.

3.1. Underutilised Crops – An Untapped Global Resource

From an estimated 390,900 known vascular plant species about 7,000 have been cultivated throughout human history as crops for food, feed, forage, fibre or fuels [30]. Of these, only about 30 crops now underpin the world’s food supply with as much as 80 per cent of plant-derived food coming from just 17 of the 452 plant families [31]. Article 11.1 of the International Treaty on Plant Genetic Resources for Food and Agriculture [32] (https://www.fao.org/plant-treaty/en/) refers to the multilateral system of access and benefit-sharing which includes all the plant genetic resources for food and agriculture listed in Annex 1 of the treaty. Despite the huge treasure trove of agricultural biodiversity that exists within the Plant Kingdom, Annex 1 of the treaty lists only 64 crop and crop complexes that are `under the management and control of the Contracting Parties and in the public domain’, - in other words of global significance. Those not listed in Annex 1, enjoy limited, variable and, in some cases, negligible support from international and national research agencies, investors and the private sector. These are the `underutilised’ or `forgotten’ crops, many of which have sustained humanity for millennia but are now marginalised [33] or ignored by modern agriculture and the research, education, regulatory and trade systems that underpin it. As a result, underutilised crops are under researched and undervalued, yet many may contain unreported properties, such as nutritional content, and characteristics, such as climate resilience, that humankind will need if we are to survive and thrive on a hotter and more populated planet.

Globally and in the UK, the dependence of agri-food systems on just a handful of crops represents a huge and unprecedented risk to food security and agricultural resilience – a risk that will only increase in an uncertain future. Climate change and weather extremes, the prevalence of intractable weeds, pests and diseases and increasing resistance to their chemical control, market volatility and vulnerable, carbon-heavy supply chains, as well as national and international commitments to sustainable land use, mean that the agrifood system must adapt rapidly to changing circumstances and priorities. The diversity of the crops that humanity chooses to grow represents part of the armoury available to meet the growing threats to food, nutritional, energy and economic security. The National Food Strategy and the Foresight Review represent important milestones in setting out an alternative vision for the UK’s food system and the innovation ecosystem that is essential for its transformation. Both documents envision the future of agriculture within a wider context of protecting nature and doing less harm to the planet whilst meeting the food needs of a growing population living in a warming world. However, whilst these documents, which together span 393 pages, include the term `biodiversity’ no fewer than 75 times, there is not a single mention of `agricultural biodiversity’, `crop diversity’ or `underutilised crops’. Nevertheless, agricultural biodiversity provides a myriad of opportunities to diversify food systems and human diets, the formulation of animal feeds, feedstock for biomaterials for energy, compounds for pharmaceuticals as well as undiscovered bioactive compounds and chemicals for new agricultural enterprises under current and future climates. In principle, underutilised crops and their products could contribute to each of the 14 recommendations in the National Food Strategy (and the Rural Land Use Framework, National Food System Data Programme and Good Food Bill that it proposes) as well as all of the seven innovation themes identified in the Foresight Study (especially vertical agriculture, protein transition and regenerative agriculture).

3.2. Diversifying UK Agriculture through Investment in Underutilised Crops

In 2021, Defra commissioned a Review of Opportunities for Diversifying UK Agriculture through Investment in Underutilised Crops (Defra Project CH0224 [34]). The objectives of the review were to: i) identify underutilised or novel crops potentially suited to the UK; ii) examine the feasibility of growing them and their potential impacts, scope how to assess productivity, sustainability and climate resilience within diverse cropping systems; iii) undertake a detailed evaluation for a shortlist of crops arrived at with the involvement of stakeholders; and iv) identify knowledge gaps and research or investment needs. The review was delivered through literature and database searches, expert knowledge and engagement with growers, advisers, breeders, seed suppliers, processors, traders, and researchers. A longlist of 192 crops was identified that included 38 cereals or grains, 19 oilseeds or seeds, 22 grain legumes/pulses, 29 forage or forage legume crops, 52 vegetables or tubers and 32 fruits, nuts or vines. These crops encompass 44 plant families, with 135 primarily having food use, 40 feed or forage, 16 pharmaceutical, and one fibre crop (with food and pharmaceutical uses). Of these, 140 are field crops, 24 orchard crops, 21 crops that could be grown outdoors or in protected environments, and 7 that could only be grown under protected conditions. To derive a shortlist of crops, fifteen criteria in five categories were classified by the project team with input from stakeholders viz.

• Crop suitability: climate; soil or growing medium, and cropping/production system
• Ease of cultivation: variety/seed/plant accessibility, agronomy, machinery, storage
• Economic potential: outputs, markets and utilisation and costs, margins and returns
• Knowledge and resources: state of knowledge and state of resources
• Environmental impact: climate change, biodiversity, pollution, soil health/protection.

The literature search identified over 600 publications which were mapped alongside expert knowledge to inform scoring of each crop against each criterion. Shortlisted crops were assessed relative to currently grown crops of similar type that they might replace. Through this process, about ten crops were selected for each crop group to produce a draft final shortlist which were then examined through a series of workshops to produce a final shortlist of four to seven crops for each crop group for more detailed evaluation viz.

• Cereals and grains: Buckwheat, Durum, Grain maize, Quinoa, Rye, Triticale
• Oilseed and seeds: Ahiflower® Hemp, Linseed, Sunflower
• Grain legumes/pulses: Chickpea, Lentil, Soya bean, Vicia (faba) bean, Yellow pea
• Forage/forage legumes: Chicory, Festulolium, Lucerne, Red clover, Ribwort plantain, Sainfoin
• Vegetable and tubers: Jerusalem artichoke, Kale, Radish, Snap/snow pea, Squash, Swiss chard
• Fruits nuts and vines: Apricot, Haskap, Hazelnut, Peach/Nectarine, Table grapes, Walnut

The review calls for the development of a framework to assess underutilised crops individually and as part of a cropping sequence, identified currently available tools, models and frameworks that could be used to assess relevant metrics and analysed the availability of data to quantify the metrics. It concluded that whilst various tools and models are available to assess some of the metrics and can be parameterised for underutilised crops, no single tool has the capability to fully assess all metrics. The review also considered potential regulatory implications of new crop varieties or their seeds, trends in global supply and demand for commodity crops, UK self-sufficiency and household food purchasing alongside an assessment of markets, trade, and utilisation for all the shortlisted crops. Key research organisations, both with a UK and an international mandate, companies and other stakeholders involved in the development, uptake, management, or utilisation of underutilised crops were mapped and representatives of UK-based institutions were invited to attend workshops or join discussions. Through this process, a series of indicators was identified that could be used to assess suitability and/or potential for each shortlisted crop. Each crop was allocated a score in the range -2 to +2 for each criterion, in relation to the indicators, based on evidence (where available), or expert judgement (if not), as follows:

• Crop very favourable/positive for criterion, or showing to a high extent 2
• Crop reasonably favourable/positive for criterion, or showing to a modest extent 1
• Crop neither favourable nor unfavourable for criterion (neutral) 0
• Crop slightly unfavourable/negative for criterion, or showing opposite to a modest extent -1
• Crop very unfavourable/negative for criterion, or showing opposite to a high extent -2

Shortlisted crops were assessed against mainstream crops of similar type, scores were then multiplied to give a weighted score for each crop against each criterion to allow crops to be ranked or filtered based on individual criterion scores as well as their total weighted scores. A survey was also carried out to gather the perspectives of growers and their advisers on the growing of underutilised crops, and their likelihood of switching from mainstream crops. Two stakeholder workshops were held and views collated through questionnaires to assess:

• Potential market size (or crop area) before premiums or crop value are eroded
• Main competition for the UK market and/or export potential
• Availability of appropriate processing infrastructure and capacity
• Collaboration through the supply chain to synchronise market opportunity and crop supply
• Ability to consistently achieve the required quality standards in the UK to meet buyer, processor, end-user or consumer expectations
• Ease of including the crops within current UK Assurance schemes such as Red Tractor
• Potential secondary uses/markets and by-products
• Any regulatory or licensing challenges associated with the crop outputs

In the review, additional studies assessed the potential regulatory implications and requirements for new crop varieties or their seeds, including Plant Variety Rights (PVR), National Listing (NL) and Seed Certification, review of data and trends in global supply/demand and trade for commodity crops, UK self-sufficiency, factors impacting on UK supply chain resilience, trends in household food purchasing and factors affecting the demand for forage crops and UK market for pharmaceutical crops. Case studies were produced for seven crops that have either been successfully introduced into UK cropping systems, or that are being grown on a small scale. The crops are Ahiflower® Hemp, Poppy, Sainfoin, Blueberries, Haskaps and Pak Choi.

3.3. Underutilised Crops Knowledge Hub

One aspect of successfully establishing a new crop that regularly featured in discussions was the challenge posed by the disconnect between producers and their potential markets. This includes how best to develop a market, deliver production levels to meet market demand and develop a supply chain with potential end-users. Engagement of growers, advisers, breeders, seed suppliers, processors, traders, crop experts, researchers and other stakeholders was an important component of the project. This took the form of the producer survey, workshops, discussions, and interviews. Identifying and sharing knowledge and experience and informing the study focus were the main purposes of the knowledge exchange activities during the project. Wider knowledge exchange focused on awareness raising and promotion of the potential for underutilised crops, and crop diversity, to form part of the solution for delivering improved resilience, environmental outcomes and nutritional outputs from crop rotations and production systems. It was observed by many stakeholders during the review that underutilised crops would benefit from more industry and/or levy board support, such as promotions and campaigns, along with more supporting information, such as Descriptive Lists of varieties, including for the shortlisted vegetable crops where there may be multiple types available. It was noted that, in many cases, the published evidence and industry know-how around underutilised crops are dispersed and difficult to access. The survey highlighted contrasting producer views as to the suitability of different crops for their farms and that this challenge could be resolved through an `Underutilised Crops Knowledge Hub’ (UCKH), which would act as a repository for relevant information sources, approaches, and best practice.

The Defra CH0224 review also identifies projects, institutions and knowledge tools that can accelerate progress on underutilised crops and with which it recommended engagement. Amongst these are EU H2020 ‘RADIANT’ (Realising Dynamic Value Chains for Underutilised Crops’) that involves three UK-based partners (University of Nottingham, The James Hutton Institute, and Crops for the Future (CFF) [35] ) (https://www.radiantproject.eu/). RADIANT is multiagency consortium of researchers, farmers, value chain actors and consumers in 12 European countries that is promoting crop diversification, environmental and agricultural biodiversity preservation, and economic development through the wider adoption of underutilised crops. Within RADIANT, CFF provides access to CropBASE a global knowledge platform for underutilised crops that allows farmers and decision makers to select crops for their location based on available information. Since 2012, in the absence of an existing system, CFF has been developing CropBASE as the first global knowledge system that focusses specifically on underutilised and forgotten crops. Information on over 2700 crops is now stored at various levels of detail in the CropBASE database. Providing an integrated database that is useful for diverse underutilised crops requires the integration of data from various stakeholders, and scientific disciplines at diverse geographic scales. Data linked at the species and sub-species level [36] has been collected and organised by CFF into the CropBASE database [37,38]. Data variables used to build the database were collected in collaboration with experts in genomics, agronomy and agrometeorology, geology, socioeconomics, and nutrition both within and outside CFF. Several use cases were developed to showcase the benefits of linking data, particularly for underutilised crops [39,40].

The Defra review (2022) proposes an online tool for the UK to enable growers or advisers to identify potential alternative crops according to their sector, system, location, climate and soil type and then reduce these to those of most importance to them, including how they could support environmental outcomes such as soil health, biodiversity, greenhouse gas emissions or carbon capture. The authors of the Defra review consider the longlist of crops and their shortlisting scores as a potential starting point for this engagement with CropBASE. The challenge addressed by CropBASE is that, unlike major crops, information on underutilised species is scarce, fragmentary and, often, anecdotal without supporting peer-reviewed evidence. Much knowledge is vernacular (unwritten) and held in the heads of farmers who have continued to grow underutilised crops for generations without the benefit of conventional research, advocacy, or access to extension services. Hence, the first step in developing a global knowledge base for underutilised crops is to collate and organise various forms of quantitative and qualitative information into a common database and a data structure that is not only easily accessible but also facilitates predictive analysis and can streamline the development of computer and mobile decision support systems.

3.4. A Framework for Crop Diversification in the United Kingdom

Jahanshiri et. al. (2023) [41] used CropBASE as a systematic framework for nationwide crop suitability assessment within the UK to improve the resilience in cropping systems and nutrition security of the UK population. An initial suitability analysis was performed using data from 1842 crops at 2862 grid locations within the UK, using climate (temperature and rainfall) and soil (pH, depth, and texture) data from the UK Met Office and British Geological Survey. In the second phase, additional qualitative and quantitative data were collected on 56 crops with the highest pedoclimatic suitability and coverage across the UK. An exercise was conducted on crops within each category using a systematic ranking methodology that shortlists high value crops across a range of traits A multi-criteria rank index was developed based on nutritional traits, adaptivity, physiological traits, other uses, germplasm, and production knowledge. Each of these categories was then broken down into specific variables for data collection. Crops were ranked by their nutritional value (macronutrients, vitamins, and minerals) and on adaptive (resistance to waterlogging/flood, frost, shade, pest, weed, and diseases and suitability in poor soils) and physiological traits (water-use efficiency and yield). Other characteristics such as number of special uses, available germplasm, and production knowledge were considered in the shortlisting. For all data points, information related to source was also recorded as metadata. The ranking was applied for crops in each category. Information from the closest relatives of crops was used to fill the gaps in available data. From a list of 1842 crops at each grid point, five crops with >70 per cent pedoclimatic suitability were chosen at the first round of selection. The list was further refined to include crops that are suitable for more than 1 per cent of the UK area. In total, there were 57 crops that met the criteria: forage (19), fodder (13), ornamental/landscape (8), environmental/soil improvement (11), medicinal (8), industrial (6), legumes (3), energy (3), fruits (3), fibre (3), cereals (2), vegetables—leafy/stem (2), starchy—roots/tubers (1), beverage (2), essential oil (1), oilseed (1), grain (1), and others (15). However, many crops are also used for more than one purpose. The shortlisted crops in each category were bulbous barley (cereal), colonial bentgrass (fodder), Russian wildrye (forage), sea buckthorn (fruit), blue lupin (legume), shoestring acacia (nut), ochrus vetch (vegetable), spear wattle (industrial), scallion (medicinal), and velvet bentgrass (ornamental/landscape). The analysis further considered steps in mainstreaming these and other potential crops based on a systematic framework that accounts for local farming system issues, land suitability, and crop performance modelling at the field scale across the UK.

3.5. Collective Action on Underutilised Crops

The increased attention among the UK research community in underutilised crops has resulted in the recognition of crop diversification as a viable option to tackle a range of issues facing the UK agrifood system. However, to move beyond advocacy, recommendation and advice will require specific pathways and routes to market for underutilised crops. This has important consequences for the future of crop diversification in the UK, as the adoption of crops is still considered to be risky and remains at the level of trial-and-error rather than a long-term national commitment to agricultural diversification. In most cases, investigations are confined to location-specific trials without an overarching approach or methodology that can be applied across locations or crops. The Defra Project CH0224 represents an important step change since it links literature and database searches, expert knowledge and engagement within the UK and stakeholders across the value chain to produce a longlist of 192 crops for the whole country and, through an iterative process, reduced these to a shortlist of 33 crops in five crop groups based on consensus and common rules. In this process, the project team brought together a significant number of the individuals and institutions involved with underutilised crops across the UK and relevant international agencies and reviewed around 600 publications which were mapped and used alongside expert knowledge to inform scoring of each crop against specific criteria. Shortlisted crops were also assessed against currently grown crops of similar type to allow growers and investors to make best available comparisons between alternative crops and the status quo.

The paper by Jahanshiri et. al. (2023) presents a different approach to the same challenge i.e. how to make wise decisions about which underutilised crops are most suitable in the UK with limited available information. Rather than bringing together existing expertise and literature, the authors took a mechanistic approach that identified a priori which novel or underutilised crops could best be grown in the UK in different agroecologies and for different purposes. They used a digital knowledge system (CropBASE) and associated mapping and modelling techniques to provide a comparative basis to derive a longlist of 1862 crops at 2862 grid locations within the UK linked with publicly available climate and soil data to produce a ranking of crop suitability across the country. Traits such as nutritional quality, adaptability, and physiological characteristics were then linked with the range of end-uses, availability of germplasm, expertise, and production knowledge to provide a final shortlist of 10 crops – one for each of 10 crop types. At this stage, the overarching and systematic approach to the shortlisting added local farming conditions, land suitability and crop modelling to provide a field scale analysis for potential end-users [42]. The framework for crop diversification introduced in this paper could be further expanded to include estimates of likely yield and economic impact after broad selection and trait ranking. If minimum field data at cultivar and species level are available, simple crop models can be developed with data from the literature analysis to determine the likely yield for crops that pass the initial suitability analysis. Conversely, if minimum field data are not available, an analysis can be performed for a wide range of varieties and accessions with known origins to shortlist possible germplasm that might perform well at any location [43,44]. Such cases can be upscaled across countries and regions for many potential underutilised crops to provide national and global suitability maps. The UK’s robust crop innovation, seed system, and variety development capacities can facilitate mainstreaming of locally neglected crops, while other crops can face regulatory issues before they can be grown within the country. The advent of new technologies to collate and analyse big data for agrobiodiversity [45] and develop automated tools for local-scale insights allows for knowledge exchange between all stakeholders. Except for the literature analysis step that requires quality control by experts, other components of the analysis can be built as tools (apps) to aid decision making at the local or field scale.

On 10 October 2023, a UK Roundtable on Crop Diversification for Agricultural and Food System Resilience, chaired by HRH The Princess Royal, was held at NIAB, Cambridge, UK at which the potential for the wider adoption of underutilised crops in the UK was discussed in the wider context of the global food system. The wide range of experts who attended the meeting illustrate that the UK is in a strong position to utilise expert knowledge and data synthesis to build multinational partnerships that develop currently underutilised crops to achieve multiple national strategic priorities including food security, biodiversity and movement towards net zero carbon.

Interestingly, the different approaches taken by Defra Project CH0224 and that of Jahanshiri et. al. (2023) produced no single crop that appeared in both shortlists. There are several plausible reasons for this difference including definitions used for what is an underutilised crop, classification of end use or crop group and criteria and weightings used for suitability indicators. The differences in outputs and approaches illustrate why it is so important to move towards a common framework of assessment. A logical way forward could be to link the mechanistic analytical and predictive tools derived from CropBASE with local knowledge and expertise across the whole value chain to provide a common framework that can be developed in the UK and globally for the wider adoption of underutilised crops that are best suited to local circumstances now and in climates of the future.