Researchers and farmers work together to reduce dependence on chemicals

At a time when the European Union's strategy to green its intensive agriculture is called into question against a background of fear of food shortages, international negotiations in Geneva are considering a reduction in pesticides and the loss of chemical inputs in nature.

In the Deux-Sèvres, since 1994 the CNRS has had a study area unique in Europe: 450 km2 of agricultural land, more than 400 farms, around forty villages.

Scientists support volunteer farmers to reduce the use of pesticides - probable sources of cancer and fatal to birds - and chemical fertilizers, water pollutants and whose prices are exploding.

David Bonneau, farmer in Mougon, scrutinizes the experimental plots.

He treats one with chemical weedkiller, another mechanically with a weeder harrow whose teeth tear up the wild plants, while a third will not be treated.

"It's dirty," he comments, hunched over the little speedwell and chickweed flowers.

However, he decided to "reduce the phytosanitary because I found these products dangerous", he says.

And "the general public is asking for less".

Farmer David Bonneau prepares an insecticide before spraying it in a field in Mougon, in the Deux-Sèvres department, on March 16, 2022 XAVIER LEOTY AFP/Archives

Mr. Bonneau made his first attempts with a neighbour's spring tine harrow.

Since then, the agricultural cooperative has invested in a more efficient model.

Yields

CNRS researchers will measure the wheat yields of each of the plots just before harvest, to find out the impact of the herbicide reduction.

In the meantime, David Bonneau sees "the savings" made on the purchase of the product and on the equipment.

"I discuss yield and savings with farmers and indirectly, this has a positive impact on biodiversity", notes Vincent Bretagnolle, research director at the CNRS.

At the CNRS center in Chizé, "we have demonstrated that conventional farmers can reduce nitrogen and pesticides by a third without loss of yield, while increasing their income because they lower their costs", he explains.

However, "even the farmers who participated in the experiment and saw the results with their own eyes did not change their practices in a flagrant way", continues the researcher.

“In many parts of the world, we are at a point where the use of fertilizers is ineffective in increasing yields,” comments Robert Finger, head of farming systems research at ETH University of Zurich, quoting the Europe and parts of Asia.

Mutual fund

Excessive use of fertilizers or pesticides can affect small and large crops.

Pepijn Schreinemachers, a researcher at the World Vegetable Center, studies market gardening in countries such as Vietnam, Laos and Cambodia.

This shows a significant overuse of pesticides.

“Farmers themselves are most affected by the misuse of agrochemicals,” says Pepijn Schreinemachers.

"Every farmer has a story of pesticide poisonings, from skin rashes to vomiting and fainting. Yet most believe strongly that pesticides are necessary."

Farmer David Bonneau prepares an insecticide before spraying it in a field in Mougon, in the Deux-Sèvres department, on March 16, 2022 XAVIER LEOTY AFP/Archives

How to change uses?

“You need a combination of factors,” explains Mr. Finger, who advocates the development of alternatives between organic and conventional.

Public policies are needed to support alternative methods, with a clear medium and long term course, to have pesticide and fertilizer prices that better reflect their negative impacts, to develop polycultures that are less susceptible to disease, suggests the researcher.

Mr. Bretagnolle calls for better support for farmers, promoting their efforts and relaxing the production standards set by the agri-food industry.

In Southeast Asia, it is necessary "to ban the most toxic products" or to make their use more expensive, while "making alternatives, in particular biopesticides, more available", indicates Pepijn Schreinemachers.

To circumvent the "risk aversion" of farmers in the face of change, CNRS researchers are considering a mutual fund which would compensate them in the event of losses linked to the reduction of synthetic fertilizers and pesticides, on a model already existing in Italy.

They also want to better involve consumers, in particular via short circuits, "so as not to leave all the weight of the transition on the shoulders of farmers".

© 2022 AFP