Potential for carbon sequestration in severely degraded temperate climate sites: Acrisol and Andosol gullies in Mexico

Aim of study: We assessed potential carbon (C) sequestration in gullies formed in Acrisols and Andosols, on the basis of long-term field restoration trials and GIS analysis. Area of study: Two field trials in Michocán, Mexico, restored with Pinus pseudostrobus, Pinus greggii and Pinus devoniana in 2005 and 2009. Material and methods: Soil C content was analyzed from field samples, and C content of aerial tree biomass of the three Pinus species was estimated by means of allometric equations. The potential restoration area was calculated with a GIS using available layers from the INEGI (Mexican National Institute for Geography and Statistics). Main results: The spatial analysis showed that 1.83% of the Mexican territory are Acrisols and 1.18% are Andosols. From which, 40.87% of Acrisols and 42% of Andosols are eroded. The area with gullies was 2810 km² for both groups of soils within the elevational range of conifer forests in Mexico. C content at the two restored sites was on average of 1.27 t/ha. Soil C content in a 30-cm depth profile was 4.25 t/ha. The potential C sequestration for an average period of 13 years for an area of 2810 km² was 3.947 megatons of C (MtC). A total of four states ‒ Michoacán, Chiapas, Oaxaca, and Puebla ‒ concentrate 89% of the possible capture. Research highlights: Severely degraded sites where gullying is dominant have a high potential for C sequestration once erosion has been controlled and plant cover has been restored.