On-farm water quality: Co-design of result-based indicators

International audience

anglais. CONTEXT: Pollution of water resources by substances emitted by agriculture, such as nitrate, pesticides, pharmaceutical residues, fecal microorganisms and microplastics, remains a crucial issue. To assess the effectiveness of pollution-mitigation projects, water quality is usually monitored at the watershed scale. In parallel, farmers and agricultural advisors use mainly means-based indicators to assess farm sustainability. In Brittany, France, the Terres de Sources project addresses the following issues: (i) individual farmers cannot assess effects of changes in their practices using result-based water-quality indicators at the watershed outlet and (ii) means-based indicators provide little information about local water quality.OBJECTIVE: The aim of this project was to gather together researchers, farmers and advisors to build operational result-based indicators that would allow farmers to estimate on-farm emissions of pollutants to water. This article highlights the implementation and outputs of a collective design process to create such indicators.METHODS: The Knowledge-Concepts-Proposals design method was implemented to explore ideas around the initial concept of “result-based water-quality indicators at the farm scale”. The method’s design process has four steps, from initiation to outputs. Emerging ideas of indicators were classified in four categories and we finally selected scientifically relevant and achievable indicators. The methods for measuring these indicators were worked during the final phase of the design process.RESULTS AND CONCLUSIONS: The main results of the design process were (i) a set of result-based indicators focused on nitrate and pesticides and related to chemical measurements and bioindicators, (ii) the development of phases of “farm characterization” and “on-farm monitoring strategy” to understand water circulation, the relevant “types of water” to sample and suitable on-farm monitoring locations. In addition, breakthrough ideas have emerged but not exploited in this project; they were related to indicators based on senses and on exposure of livestock to pollutants. Despite fixation effects, the group was actively involved in the design process and in the proposal of subsequent prototype testing on farms.SIGNIFICANCE: Most of the indicators selected had already been developed at the watershed scale, but attempting to adapt them to the farm scale was an originality. Farm-scale studies help understand sources of pollutant emissions that decrease water quality. Farmers’ use of comprehensive assessment tools would help encourage them to pursue their efforts in agroecological transition.