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Intercropping: An EU Sustainable Solution through Traditional Agriculture

EU-funded project Leguminose is set to move the little-used farming method of legume-cereal intercropping into the mainstream.

Last September, at the 77th General Assembly of the United Nations, Germany’s government pledged €1.5 billion (US$1.6 billion) annually for international biodiversity conservation starting from 2025. The promised funds come at a time when the race is on to protect ecosystems and bolster biodiversity.

As Federal Environment Minister Steffi Lemke remarked: “If we do not halt the global destruction of habitats and species extinction, we will destroy the foundations of our own lives. […] Increasing our biodiversity finance … is thus also an investment in the future.”

Nevertheless, one problem standing in the way of future environmental conservation is farming. According to the United Nations, by 2050, there will likely be almost 10 billion people on the planet, and food production will increase by 60%. However, with current agriculture practices – such as intensive use of fertilisers and monocropping – there is a risk of undermining these environmental goals.

A solution to this problem may come from intercropping, a farming technique where two or more plant species are grown together in the same field. 

The practice is nothing new for Europe. However, what is new is the recent approach of growing legumes, such as beans, peas, and lentils, side by side with cereals, including barley and wheat. This is something that one European research initiative is now proposing for the first time.

EU-funded LEGUMINOSE is a project focused on biodiversity that aims to make the little-used, sustainable farming method of legume-cereal intercropping mainstream across the old continent. Together, researchers and farmers are exploring how to best grow legumes side by side with cereals. Key benefits of this practice include better crop and soil health, plants that are more resilient to disease, pests, and extreme weather conditions, and reduced use of pesticides and fertilisers.

“We’re focusing on legumes with cereals, as they are the most widely produced agronomic product,” explained LEGUMINOSE researcher Dr Norman Gentsch from the Institute of Soil Science at the University of Hannover, Germany in an interview with the European Science Communication Institute (ESCI) for Earth.Org.

“Other types of intercropping, such as maize with grassland species are common [across Europe] but intercropping a cereal with a legume is niche.”

As Gentsch points out, intercropping with legumes has critical advantages. For starters, legumes add nitrogen to the soil – nodules in the plant roots contain Rhizobium bacteria that convert atmospheric nitrogen into ammonia, which is then used in growth. 

“If you crop a legume with a cereal, the cereal can use the nitrogen from the soil,” he explained. “So, we see the legume increasing the microbial parameter in the soil that then generates higher soil fertility – this means we can use fewer fertilisers.”

In an interview conducted by ESCI for Earth.Org, Dr Shamina Imran Pathan, LEGUMINOSE coordinator from the Department of Agricultural, Food, Environmental and Forestry Sciences and Technologies at the University of Florence, Italy, highlighted how the build-up of large and active microbial biomass in the soil could help to release minerals, such as phosphorus, that are critical to plant growth.

“Not so much research has been done on how inter-cropping affects below-ground microbes, especially the functional diversity of microbial communities, so we hope to go much deeper in this project,” she added. 

Benefits aside, the project will also address myriad potential barriers that farmers face when adopting legume-cereal intercropping. For example, growing more than one type of crop demands machinery to separate the seeds from each plant as well as different harvesting equipment.

At the same time, different types of herbicides and pesticides are required for legumes and cereals. Regional barriers will also be explored. Pathan highlighted how, for example, intercropping in the Mediterranean regions will require more irrigation than in Northerly areas. 

“We may also need to change mindsets in some regions – farmers really want to know exactly why they should adopt a new technology or management practice,” she added.

To overcome obstacles and enhance farmers’ acceptance of legume-cereal intercropping, LEGUMINOSE partners are establishing a network of seven research field trials and 180 on-farm living labs across Europe, Egypt, and Pakistan. Research field trials will focus on aspects such as pesticide reduction, soil and crop health, and crop quality. 

As Pathan explained: “We’re going to be doing a lot of sampling to understand how changes in soil microbial communities affect the multi-functionality of soil and then plant growth.”

“We can test monocultures against intercropping and compare data on crop yields, quality and health,” added Gentsch. “We can also look at, say, different seeding rates, fertiliser regimes and management [regimes], and assess which approach is more efficient, and if we can also reduce the fertiliser input for a crop per hectare.”

At the same, the living labs will allow researchers to work with farmers to explore the motivation behind adopting legume-cereal intercropping. Each living lab will have different climate and soil conditions and serve as a ‘lighthouse’ for its region. As part of this, project partners hope to establish a legume-cereal intercropping value chain across Europe that will include farmers, researchers, seed growers, machinery manufacturers and food producers.

“With our UK partners, we have contacted a machinery company that has a prototype that can separate mixtures of up to five different seeds and also de-hull legumes,” highlighted Pathan. 

“In Italy, we’ve also found a company that makes pasta from legumes – these are the kinds of stakeholders we’d like to include in our value chain.”

Importantly, data from both research field trials and the on-farm living labs will be used to develop artificial intelligence-based forecasting models. Modelling results will be embedded into an interactive web tool –currently under development – that farmers can then use to select the most suitable combination of crops for their needs.

As Pathan pointed out, users will be able to integrate detail on their farms and the climate conditions into the tool to glean the ideal intercropping strategies. But, as she added: “The climate is changing all the time, so farmers need to be aware that strategies will change.”

Looking forward, both Pathan and Gentsch are excited about LEGUMINOSE and are hopeful that farmers will receive the information they need to make a profitable and sustainable transition towards legume-cereal intercropping. As Gentsch pointed out, even today, many farmers have not had a chance to learn about biodiversity and different sustainable farming methods.

“But there is more to education than schools, and we’ve been getting a lot of good responses from farmers on the webinars, tutorials and YouTube videos we provide,” he said. 

“With LEGUMINOSE, we’re really going to understand how we can have more resilient agricultural production systems.”

Source: earth