Agroecology key to reducing agricultures environmental footprint

Field trials led by The James Hutton Institute in collaboration with farmers in Scotland and overseas have demonstrated that cultivating different crops together in the same field and at the same time can make agriculture more resilient and environmentally sustainable.

The Institute is at the forefront of highly practical research into how agroecology(the application of ecological principles to farming practices) can help reduce the agriculture sector’s environmental footprint, contribute to more sustainable and secure food production, and build more innovative and resilient farming businesses.

Alison Karley, Research Leader in Agroecology and Pete Iannetta, Head of Ecological Food Systems at the Institute have led several Scottish Government and EU-funded research projects exploring sustainable farming practices. This includes intercropping, which involves growing a combination of crops together, with a particular focus on growing legumes such as peas, beans, and clover alongside other crops.

“We’re seeing great examples of agricultural innovation in Scotland,” says Alison Karley. She has been involved with intercropping field trials run at the institute’s farm and she coordinated the EU project DIVERSify (Designing InnoVative plant teams for Ecosystem Resilience and agricultural Sustainability). 

“We work with crop scientists, breeders and farmers to identify the traits of specific crop pairings that will optimise the benefits of intercropping, and the agronomic practices needed to grow and harvest them. The participatory and collaborative element of our approach is very important,” she adds.

As well as running field trials on the Institute’s own farmland, Karley’s team have worked in partnership with farmers and crofters across Scotland. These include trials on the tiny island of Lismore in the Inner Hebrides where farmers grew a pea-oat intercrop alongside a traditional ‘Uist’ cereal mix of bere barley, black oats and rye.

“We hope that sharing field trial data and practical knowledge can encourage wider adoption of agricultural practices that are environmentally and economically sustainable, and so are good for people and for the planet,” Karley says.

The Institute has worked in collaboration with international research partners on several major projects that have demonstrated numerous positive impacts of intercropping. These include higher crop yield and quality, improved soil fertility, enhanced biodiversity, more efficient use of critical resources such as water and reduced dependence on synthetic fertilisers.

Intercropping can take many forms - from sowing several crops simultaneously next to each other to sequential or relay planting. It can involve ‘companion crops’ that can help protect a main cash crop from damage by weather, weeds, pests or diseases. It can also take the form of ‘cover crops’ that are grown over winter to improve soil structure and protect against soil erosion.

The principle is that careful selection of crop pairings can enable two or more crops to flourish side by side, yielding a better crop than when grown alone. Intercropping also has a beneficial impact on soil health as it leaves more nutrients in the ground to help the next season’s crop as well as potentially reducing the need for fertilisers and pesticides.

It is a practice that dates back to ancient times. It was traditional in Scotland for oats and peas or beans to be grown together in intercrop known as a “mashlum”. The flour of grain from the mixed crop was also used to make bannocks. Besides being a low input cropping approach, the protein forms of the oats and pea in mashlum were complementary and delivered a standard of nutrition that was more complete than either crop could alone.

Pete Iannetta, says environmental problems associated with modern agriculturestem from many years ofinput-intensive farming and a focus on maximising yields by growing single crops. This has become a bigger concern in the context of a global biodiversity crisis, concerns over food security and a growing population to feed.

There is also a serious shortage of the most critical fertilisers - nitrogen, phosphorous and potassium. Iannetta says that in terms of environmental impact, synthetic fertiliser production is energy-intensive which results in a large carbon footprint. “Also, approximately half of all fertiliser added is not absorbed by crops and ends up polluting soil and water,” he adds.

War in Ukraine and a spike in energy prices has highlighted vulnerabilities in the security and sustainability of the wider agricultural and food supply chain. Not only are Russia and Ukraine major grain exporters, Russia is also the world’s top exporter of nitrogen fertiliser and second in phosphorus and potassium.

This has created a perfect storm in the agricultural sector, intensifying the need for agroecologists and farmers to work together to develop and trial new solutions.

Iannetta led an international research project called TRUE (TRansition paths to sUstainable legume-based systems in Europe), involving 10 European nations plus Kenya. This included analysing how intercropping with legumes can increase farm biodiversity and create a more diverse landscape for animals.

Modern intercropping frequently involves growing cereals such as barley or oats alongside legumes like peas or beans. The TRUE project trialled different combinations of legumes and other crops in diverse farm environments in terms of soil and climate.

Iannetta says a unique attribute of legumes is their ability to act as natural fertilisers, absorbing nitrogen from the air and adding it to soil in a usable form through their roots. This is good for farmers and the environment as it can reduce the need for synthetic fertilisers.

“Legumes are important sustainable food crops for many reasons,” says Iannetta.  “It’s frustrating when they are talked about mostly as fertiliser or meat replacements. They offer much more than that for farming, humans, and farmed animals – including fish.”

Studies show that eating legumes like lentils and beans contributes to improved cardiovascular and gut health. It also helps tackle obesity and inflammation and can help modulate blood sugar and blood pressure.

Iannetta says farmers in Scotland are blazing a trail in demonstrating how legumes can create new and diverse sources of income.

The Stirling family, fourth generation farmers in Arbikie in Angus, created the world’s first carbon neutral climate positive gin. Their gin includes peas, juniper, lemongrass and citrus leaf botanicals all grown on their own farm.

They built their own distillery in an old barn and their gin is now served in London’s Savoy hotel and other top hotels and bars around the world. Less glamorous, but equally important, the leftover pea mixture is used as animal feed. The gin, grown and distilled entirely on the farm estate actually has a negative carbon footprint.

The Institute also collaborated with Abertay University to create Barney’s Cool Beans IPA, a novel beverage made with 40% faba beans and 60% barley.

Karley and Iannetta are encouraged by evidence of farmers embracing agroecological principles and practices. However, they acknowledge that significant barriers to wider adoption remain. The most significant include a lack of knowledge and experience and established farm economics and post-farmgate food systems geared towards maintaining long-standing practices. 

Karley says by working directly with farmers, the Institute gathers insight and shares knowledge that can help address complexities surrounding particular soil or climate challenges, sowing and harvesting techniques, optimum weed and pest controls and any required adaptations in farm machinery.

“We see great potential for farmers in Scotland and other farming nations to be innovators and agents for change in agriculture, and food systems generally.  We will continue working with farmers to help them realise environmental, economic, and social benefits and to build more resilient and sustainable businesses.”

Disclaimer: The views expressed in this blog post are the views of the author(s), and not an official position of the institute or funder.