Impact of mountain grassland irrigation in nitrous oxide (N2O) emissions
A better understanding of the impacts of irrigation on N2O emissions to develop more sustainable agricultural practices
Challenges addressed
Irrigated mountain grasslands are part of a patrimonial landscape in Wallis and their water consumption is being optimised in the Entremont region by the ODILE consortium (Optimisation de l'Irrigation dans l'Entremont) to anticipate the impact of climate change on water demand. N2O is a major contributor of direct agricultural greenhouse gas (GHG) emissions in Switzerland. Furthermore, changes in precipitation patterns and increasing drought may enhance N2O emissions from soil, due to their dependence on soil moisture (i.e. redox processes). Thus, there is an urgent need to assess the irrigation-dependent dynamics of N2O emissions.
Here, the team investigates the impact of irrigation and management practices on these emissions in mountain grasslands, in order to provide best practice recommendations for farmers that minimise both water-use (adaptation) and emissions (mitigation) in the context of a changing climate.
Objectives
The team intends to investigate the impact of both irrigation and management practices on N2O emissions and identify the underlying processes responsible for these emissions. The hypothesis is that low fluctuations in the soil moisture content is the optimal strategy as it minimises water-use and N2O emissions and maximises plant growth. The project aims to use measurements to link irrigation and N2O emissions along a growing season in mountain grasslands in the Entremont region.
What are the expected outputs of this project?
- To address two concerns, one scientific and the other societal: Is soil moisture content a controlling factor for N2O fluxes? And what are optimal agricultural practices to minimize these fluxes?
- To help develop adaptation and mitigation practices to climate change based on scientific evidence and that optimise the relevant agricultural parameters in the Entremont region, namely productivity, fertilization, water-use, and GHG emissions.
Milestones
- October to December 2022
Stakeholder engagement + Meeting and presentation of the project to farmers on 11 November in Orsières
- February 2023
Selection of two experimental sites. Two sites identified: ODILE irrigated site in Val de Bagnes and a fully controlled experimental site in la Rosières (Orsières)
- March to April 2023
Master’s student laboratory training
- May to September 2023
Sampling and analysis
- October to December 2023
Reporting and publications
- November 2023
Factsheet and presentation to public administration + Search for additional funding and project extension
Funding
This project is financed by CLIMACT.
In-kind contributions: Fondation Aubert, Champex-Lac Infrastructure: ODILE platform, ALTIS, Hydrolina and Commune d’Orsières
Gallery
Principal investigators
Prof. Rizlan Bernier-Latmani
Full professor in Environmental Microbiology
ENAC, EPFL
Dr. Christophe Randin
FBM DEE, UNIL
