About the assessment of cover crop albedo potential cooling effect: risk of the darkening feedback loop effects

Recent studies show that the introduction of cover crops over Europe could result in a cooling impact due to an increase of soil organic carbon stocks, a decrease in the use of fertilizers, and an increase in surface albedo of the croplands. This article analyses the impact of the introduction of cover crops over Europe during the fallow periods. Compared to previous studies, this work discusses: i) the maximum greening potential in Europe, and the associated indirect surface properties changes ii) for snowfall episodes and iii) due to an increase of organic matter. This study shows that the mitigation potential of cover crops through albedo effects could reach 6.74 MtCO2-eq.yr-1 by extending the periods of introduction of the cover crops to all possible fallow periods. This mitigation could be limited to 5.68 MtCO2-eq.yr-1 if the impact of snowfalls is considered. This would be equivalent to 9.12 gCO2.m-2.yr-1. This study investigates the feedback loop due to soil darkening with soil organic carbon content increase when cover crops are introduced, considering two scenarios. The first considers the soil organic carbon content increase following repeated incorporation of cover crop biomass into the soil, simulated with the DayCent model. The second, more conceptual and extreme scenario aims at alerting on the possible impact of a combination of carbon farming practices such as biochar or organic amendments. Our results show that this effect could lead to a loss of 20% of the climate benefit.

PIQUE Gaétan;  CARRER Dominique;  LUGATO Emanuele;  FIEUZAL Rémy;  GARISOAIN Raphaël;  CESCHIA Eric; 

2023-08-09

MDPI

JRC133742

2072-4292 (online),   

https://www.mdpi.com/2072-4292/15/13/3231,    https://publications.jrc.ec.europa.eu/repository/handle/JRC133742,   

10.3390/rs15133231 (online),