Scotland has ambitious strategies for biodiversity protection and climate action with the intention of achieving a greener, fairer and just future. As most land in Scotland is devoted to some form of agricultural production, farmers and land managers are key players in achieving a transition to more sustainable agriculture and horticulture. We have tested an array of farming practices that could improve sustainability, by using fertilisers from non-chemical sources, identifying crop varieties that perform well in intercropping and under reduced input conditions, and safeguarding biodiversity by increasing crop and non-crop diversity. While these practices have been tested and demonstrated at research scale, innovative ways are needed to test their practical application by farmers and share knowledge widely in the Scottish farming community.
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Research over recent years, supported by the Scottish Government and other funders, has shown that intercropping – the practice of growing two or more crops as a mixture in the same field - often produces higher yields than the crops grown separately (referred to as overyielding) and with fewer agrochemical inputs, while also providing biodiversity benefits. Although these potential environmental and financial benefits are widely recognised, intercropping is not commonly practiced in modern farming.
One of the main challenges of adopting sustainable farming practices is they tend to be knowledge intensive and rely heavily on understanding the ecological processes in agricultural systems and how to optimise certain biological functions whilst reducing use of synthetic fertilisers and crop protection chemicals. Our discussions with farmers and other agricultural stakeholders highlighted the challenges they encounter when seeking to increase their knowledge about the practicalities of growing and harvesting crop mixtures, and the uncertainty about what would work best on their farm.
To address this, we conducted on-farm trials across Scotland with a network of farmers who were interested in using crop mixtures. The aim was to instil new intercropping expertise with a group of farmers while also collecting data to validate intercrop performance at sites from the Northeast of Scotland to the Borders. To ensure lasting benefits for farmers across Scotland, we developed a new online tool where intercrop trial data can be openly viewed and explored, aiming to encourage others to share their crop mixture data and feedback their experiences.
In 2020 and 2021, intercrops selected by farmers were sown in their own farm trials in North-eastern, Eastern and central Scotland and the Borders, complemented by trials carried out at the James Hutton Institute’s Balruddery Farm. The crop mixtures consisted of a cereal (barley, oat, wheat or rye) grown with a legume (pea, faba bean, clover or vetch) or an oilseed (linseed), and each trial included at least one of the mixture components grown in monoculture for comparison.
The trials were monitored and sampled by farmers and institute scientists to assess mixture performance and ecological benefits, such as the biodiversity of soil organisms, pest and weed control, soil nutrient availability and crop yield. Data analysis showed that crop total productivity was similar or higher in intercrops compared with monocultures (Figure 1), and overyielding of the grain product was observed with some mixtures. Intercrops generally suppressed weeds at all sites, and aphid numbers were lower on pea plants grown in mixtures in the institute’s farm trial (see Figure 1). We are currently processing samples to understand whether crop mixtures improve soil fertility and the biodiversity of soil microbes and nematodes.
Figure 1. Weed biomass was lower and crop biomass was higher in pea-barley mixtures compared with monocultures (left panel). Aphid numbers were lower on pea plants grown in mixtures (middle panel). Data are shown for the institute’s pea-barley intercrop trial conducted in 2020 (right panel).
The farm trial datasets were collated into a database and discussions were held with project partners to understand the most useful way of presenting the data online. This co-development approach identified some key features: that trial data (e.g., yield) and meta-data (e.g., sowing and harvest times, details of inputs, farm management methods) should be presented in text and graphical formats with the option of delving further into the details of each trial.
Based on this advice, we developed an open data platform comprising a website where users can search through trial datasets using filters such as crop species in the mixture, soil tillage, or farm management (e.g., organic, LEAF). The datasets for the filtered trials are shown in a table, with clickable icons where more trial details are revealed (Figure 2). The yield data for the selected trials are also shown visually on a map, both for the mixture and the monocultures, with the option of colour-coding trials by farm type, soil tillage and other management actions (Figure 2). The user can also plot trial measurements in graph form and colour code the results (Figure 2). Finally, there is a clickable link allowing platform users to upload their own crop mixture trial data to the database using a simple online data submission form.
Figure 2. The Crop Mixtures Data Explorer tool created at the James Hutton Institute. Filtering the crop mixtures database for pea-barley intercrop trials returns farm trial datasets in table (left panel) or map (middle panel) formats. Data can also be plotted in graphical format (right panel).
Through open and participatory agricultural research between farmers and scientists, our crop mixtures pilot study builds on experience gained from current and recent intercropping projects (SEAMS - Esmée Fairburn Foundation; NOVELLA – Mains of Loirston Charitable Trust; DIVERSify – EU Horizon 2020) to show how farm-based trials can provide accessible data to aid farmers’ decisions about sustainable cropping practices.
The research has supported uptake of intercropping by a growing number of farmers who are looking for practices that increase future sustainability and reduce the environmental footprint. Bringing researchers and scientists together has benefits for both participants: farmers gain from access to scientific advice in conducting and evaluating research trials while scientists gain a better understanding of how their research translates into practical use. This increased connection and accessibility also brings wider benefits to society, such as a deeper appreciation of the mechanisms needed to support sustainable farming and the potential rewards.
The open data interface and data submission form is available online at the weblink below and will continue to be developed in response to user feedback. You can help us by visiting the website and letting us know how we can make improvements.
Game and Wildlife Conservation Trust,
Linking Environment and Farming UK,
National Farmers’ Union Scotland
NatureScot, Royal Highland Education Trust
Soil Association Scotland
- Supply chain perspectives on breeding for legume–cereal intercrops. Frontiers in Plant Science
- Does crop genetic diversity support positive biodiversity effects under experimental drought?
- Root traits with team benefits: understanding belowground interactions in intercropping systems
- Intercropping in high input agriculture supports arthropod diversity without risking significant yield losses
- Grain Yield Stability of Cereal-Legume Intercrops Is Greater Than Sole Crops in More Productive Conditions
- Facilitation and Biodiversity Ecosystem Function (BEF) relationships in crop production systems and their role in sustainable farming