Intensive agriculture leads to soil degradation, yet agriculture will need to produce increasingly large amounts of food to meet the demand of a growing human population. High-intensity tillage can result in a decline in soil organic carbon (SOC) stocks and increase in greenhouse gas emissions from agricultural soils. To avoid these negative effects, alternative tillage practices, such as no-till or reduced tillage are increasingly being promoted. However, previous studies report contrasting overall effects of tillage practices on SOC stock. To determine the protective and/or restorative effects of alternative tillage practices, it is therefore critical to identify the biogeochemical mechanisms that drive SOC dynamics under different tillage practices.
The goal of the project TilSoilC is to establish a link between tillage practices and mechanisms of SOC stabilization. We will study mechanisms of SOC stabilization across a spectrum of young to highly weathered soils in Africa and Europe (tropical (oxisols), Mediterranean (terra rossa, chromic luvisols), and cool-temperate (cambisols) soils). We hypothesize that tillage negatively affects SOC stocks and persistence through the breaking up of organo-mineral associations and aeration of oxygen-depleted zones in the soil. We further postulate that soil mineralogy is a major control on tillage-induced SOC losses, with soils dominated by low-activity clays being the most prone to SOC losses and soils dominated by oxides being the least prone to SOC losses. To test our hypotheses, we will sample top- and sub-soils from agricultural fields which have been subjected to different long-term tillage intensities and assess their physico-chemical properties, mineralogy, microbiology, and organic matter properties.
The TilSoilC project is funded through the European Joint Programme on Soil. The project consortium consists of four partners EPFL (Prof. Meret Aeppli), Unil (Dr. Stéphanie Grand), University of Basilicata in Italy (Prof. Adriano Sofo), and the University of Dschang in Cameroon (Dr. Georges Ndzana).
People: Orly Mendoza
Collaborators: Stéphanie Grand, Adriano Sofo, Georges Martial Ndzana
Funding: European Joint Programme on Soil