Smallholder farmers have to grow as much food as possible on very little land, while the weather becomes more extreme and harder to predict. Synthetic pesticides help, but they also harm ecosystems and human health. The EU-funded UPSCALE project tested whether plants themselves can protect maize from pests, and its team carried out more than 150 interviews with farmers and experts along the way – and at the end you can check whether there is room for nature in your own everyday choices.
Subsistence farms cannot afford to waste space. A limited plot has to feed a family and provide a living. On top of that, the climate is becoming more extreme and less predictable, so farmers have to adapt while they work.
At the same time, the price of conventional intensification is well known. Synthetic pesticides and fertilisers can damage ecosystems and human health. The UPSCALE project therefore asked a simple question: what if the mechanics of natural systems could be used to produce more per hectare, in a way that is climate-resilient and good for biodiversity?
To look at agroecological ways of raising yields, the project focused on an approach called push-pull. The project coordinator, Emily Poppenborg Martin, professor of Animal Ecology at the Institute of Animal Ecology and Systematics at the University of Giessen in Germany, describes it like this: “Push-pull is a way of managing crop pests from the bottom up. It uses the way that species interact with each other to repel (i.e. ‘push’) pest insects outside maize fields, and/or to trap them (i.e. the ‘pull’) within or on the borders of the crop.”
In practice, it works like this:
“In effect, we are enlisting nature to protect the crops,” Poppenborg sums up.
The method has many benefits, but how well it works varies a lot from region to region. According to the coordinator, the fields around a crop can strongly affect the ecological interactions inside it – and this had barely been investigated before.
The second problem is a social one. Farmers adopt push-pull less often than its potential would suggest. “So, in UPSCALE, we set out to understand this variability, to identify how and when push-pull could be best integrated into farming systems, and what it would take to scale an agroecological technology like the push-pull,” says Poppenborg.
The researchers used a whole set of tools. With traps they sampled beetles, spiders and flying insects – the natural enemies of maize pests. They surveyed the maize plants to see how much damage the pests had done, and harvested the maize to measure yields.
They also used novel field sensors to capture the volatile substances released by the plants in the intercropped system. Satellite remote sensing helped them map land use and assess how vegetation responds to climate factors. Finally, the team modelled how changes in the wider social-ecological system affect push-pull.
Technology is only half the story. To understand why farmers hesitate, the team conducted over 150 interviews with smallholder farmers and expert informants in three survey waves. Together with stakeholders, they assessed the benefits and mapped out value chains. “We identified barriers and opportunities for scaling, and co-designed roadmaps for when, where and how to scale push-pull practices,” the researchers explain.
The project then co-designed trials with farmers and piloted new ways of spreading the method. One of the hurdles turned out to be livestock roaming freely around the fields.
UPSCALE worked with whole communities. Farmers and researchers designed solutions together, such as live fencing and nurseries for Desmodium plants. Farmers also co-designed and tested ways to rotate crops and to combine push-pull with other food crops, such as tomatoes and kale.
“For me, the most striking finding is the importance of communities and critical mass,” says Poppenborg. When an entire community implements push-pull together, social networks get stronger and people make the technology their own, adapting it to their needs and developing new, creative value chains.
Push-pull has been included as a climate-resilient approach among the nationally recognised agroecology strategies of the partner countries. The partners are now focusing on bringing the lessons learned into agricultural extension services and into the design of policies that support agroecological transitions.
For students of agriculture, biology, environmental science or rural sociology, the project is a good example that food research is not only about insects and plants, but also about talking to the people who are expected to change their habits.
Push-pull uses plants to repel and trap pests, so maize needs fewer pesticides. The UPSCALE project combined traps, sensors, satellites and models with more than 150 interviews to find out when and where the method works best. Its most important lesson is about people: the technology takes root best when a whole community adopts it.
This article is based on material published by the European Commission’s CORDIS service.
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