Trace gas emissions from soil of the central highlands of Mexico as affected by natural vegetation: a laboratory study

Angoa Perez, M.V.; Gonzalez Castaneda, J.; Frias-Hernandez, J.T.; Franco-Hernandez, O.; Cleempt, O van; Dendooven, L.; Olalde, V.

Trace gas emissions from soil of the central highlands of Mexico as affected by natural vegetation: a laboratory study

2004

In the central highlands of Mexico, mesquite (Prosopis laevigata) and huisache (Acacia schaffneri), N2-fixing trees or shrubs, dominate the vegetation and are currently used in a reforestation program to prevent erosion. We investigated how natural vegetation or cultivation of soil affected oxidation of CH4, and production of N2O. Soil was sampled under the canopy of mesquite (MES treatment) and huisache trees (HUI treatment), outside their canopy (OUT treatment) and from fields cultivated with maize (ARA treatment) at three different sites while production of CO2, and dynamics of CH4, N2O and inorganic N (NH4+, and NO3-) were monitored in an aerobic incubation. The production of CO2 was 2.3 times higher and significantly greater in the OUT treatment, 3.0 times higher in the MES treatment and 4.0 times higher in the HUI treatment compared to the ARA treatment. There was no significant difference in oxidation of CH4 between the treatments, which ranged from 0.019 g CH4-C kg-1 day-1 for the HUI treatment to 0.033 CH4-C kg-1 day-1 for the MES treatment. The production of N2O was 30 microgram N2O-N kg-1 day-1 in the MES treatment and >8 times higher compared to the other treatments. The average concentration of NO3- was 2 times higher and significantly greater in the MES treatment than in the HUI treatment, 3 times greater than in the OUT treatment and 10 times greater than in the ARA treatment. It was found that cultivation of soil decreased soil organic matter content, C and N mineralization, but not oxidation of CH4 or production of N2O.

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