Edaphic microbial CO2 in a forest of Abies religiosa (Kunth) Schltdl. & Cham. in Mexico City

Abstract

Microbial respiration plays a key role in the C cycle and contributes to the production of CO₂, so it is important to identify the changes and agents that alter microbial communities and, therefore, soil respiration rates. Few studies have focused on characterizing microbial respiration in urban forests subject to changes in land use. The production of microbial CO₂ from the soil of six sites with different tree cover in an Abies religiosa forest (0, 100, 170, 180, 240 and 310 cm²) was examined, and its relation with soil properties in the Magdalena river basin in Mexico City. A plot of 25 × 25 m was established in each site, the basimetric area was obtained and the shrub and herbaceous species were identified, soil were collected to measure the CO₂ released by the microbial biomass (bacterial and fungal). The gravimetric moisture content, bulk density, pH, and total C and N were measured too. The CO₂ from the fungal biomass was highest than the bacterial; highest values were observed in the rainy season. A positive linear relationship was found between CO₂ and the moisture content, bulk density, pH and C/N ratio. The soils of sites that are in in early stages of natural regeneration with less basimetric area, produce a high release of CO₂. Vegetation and soil properties influenced microbial activity.