A 10-year experimental study shows the potential of pesticide-free agricultural production

The widespread and repeated use of pesticides has major impacts on the environment (soil, water and air pollution), human health and biodiversity, and comes with a non-negligible economic cost to both society and farmers. Can the use of pesticides be stopped on arable crops without compromising yields and economic viability? The Rés0Pest experimental network, coordinated by INRAE and involving the Purpan Engineering School, CIRAD and the Iowa State University, has released its findings after 10 years of research.

Rés0Pest, created in 2012 as part of a call for projects under the Ecophyto DEPHY EXPE programme, looked at nine original cropping systems that used no pesticides but did have the option to use ploughing and synthetic fertilizers. These systems were developed during co-design workshops held in nine locations in France with extension specialists, farmers and researchers. The workshops covered a wide range of pedoclimatic conditions and socioeconomic contexts (five arable cropping systems and four multicrop-livestock systems including temporary meadows) within INRAE’s network of experimental units, which are open-air labs managed by the Institute’s engineers and technicians. 

The goal was to use zero pesticides while reducing biotic stress as much as possible (caused by pests, fungi and weeds), with rotations that varied from 5 to 9 years. The success of the tested systems was underpinned by a three-pronged approach to agroecological crop protection principles:

• prevention (e.g., management of infected crop residues, use of healthy seeds, cleaning of agricultural machinery)
• reliance on plant biodiversity (e.g., long and diverse crop rotations, with different crop families and sowing periods; companion crops and varietal mixtures)
• improvement or protection of soil health (e.g., stopping the use of pesticides, cover cropping, limiting but not fully excluding ploughing)

The use of mineral fertilizers was allowed in these cropping systems.

The yields of the various cropping systems were measured. When the results were compared with Agreste¹ data (at the regional scale of comparable contexts), the conventional pesticide-free systems produced yields that were often below those of conventional systems using chemical protection products, although in some situations, they reached equivalent levels or even exceeded them. Damage from pests and diseases did not increase significantly over time.

However, weed management continued to be a challenge in some situations, especially for docks and sorrels² in temporary meadows. It should be noted that weed management within the network did improve over time, which is crucial given the long-term consequences that poor weed management during one season can have, since it increases the weed seed bank in fields. In some cases, managing weeds required ploughing, a practice that runs contrary to soil conservation principles.

Over the 10-year study, the four conventional arable cropping systems for which the economic performances were quantified (Auzeville, Bretenière, Estrées-Mons and Grignon) produced a satisfactory net margin, which in 20% of cases could result in incomes equal to or double the national minimum wage, in 45% of cases double or triple the national minimum wage, and in 35% of cases more than triple the national minimum wage.

These results show that the conventional, pesticide-free arable cropping systems can be productive and technically and economically feasible. However, creating such production systems involves diversifying crop rotations, developing appropriate marketing channels, and determining the economic value of the products from these systems. To do this, appropriate public policies are needed to support their widespread adoption. These findings also add to European discussions³ on accelerating the agroecological transition.

These analyses of agricultural, economic, environmental and social outcomes will continue with the 0phyto project, launched in 2025. This project will build on the progress made through Rés0Pest and extend to organic farming by integrating data from the Organic Food and Farming Institute (ITAB) on organic cropping systems. The French Statistics and Forecasting Department (for agriculture, food, forestry and fishing).

_{1. The French Statistics and Forecasting Department (for agriculture, food, forestry and fishing).}

_{2. Perennial weeds that are especially problematic for cropping systems.}

_{3. The Rés0Pest findings will support discussions through the European alliance “Towards a Chemical Pesticide-Free Agriculture”, which includes 34 research institutes from 20 European countries.}

“We tested the feasibility and performances of pesticide-free cropping systems based on a conventional approach, i.e., allowing the use of synthetic fertilizers. INRAE, as a public research stakeholder, must take risks to explore the full realm of possibilities.” Jean-Noël Aubertot, INRAE Research Director at the Agroecology, Innovations and Territories Joint Research Unit.