Resumo

CRUZ-FLORES, Gerardo  e  ETCHEVERS-BARRA, Jorge D.. Organic carbon content of shallow soils in pine and spruce forest located in mexican protected areas. Agrociencia [online]. 2011, vol.45, n.8, pp.849-862. ISSN 2521-9766.

Soil organic carbon (SOC) contents, from microbial biomass (MBC), and metabolic coefficients (qCO₂) are indicators of sustainability. In México there is a lack of information about the optimal level of SOC, MBC and qCO₂ contents in temperate forests, although understanding these is important for the design of adequate use and management strategies in forest soils, which are generally shallow and vulnerable. This study was carried out in nine natural protected areas (NPAs) in México with temperate forests over soils developed from igneous, sedimentary or complex metamorphic material. Between 2004 and 2009, 187 sites were selected with mature stands of species from the Pinus and Abies genera, where superficial soils were collected to determine whether the SOC, MBC, qCO₂ and necromass carbon (NMC) contents are affected by the type of parent material in the soil or because of the presence of Pinus or Abies species, where those best represented were Pinus montezumae, P. tecocote, P. patula, P. pseudostrobus, P. hartwegii, P. lawsoni, P. ayacahuite var. oaxacana, Abies religiosa and A. vejarii. The average SOC content was higher than 100 Mg C ha^-1 and the MBC ranged from 0.25 to 2.6 Mg C ha^-1. After the soil, litter forest was the second reserve for carbon (NMC), with an average of 45 Mg C ha^-1. Forest soils over sedimentary and metamorphic rocks had greater SOC contents (lower MBC proportion, higher C:N rates and lower microbial efficiency) than those observed in soils derived from pyroclastic material (lower C:N rate and greater microbial activity). Under Pinus species, there was less SOC than under the Abies genus, in whose forests there were herb and shrub strata with greater plant diversity that contributed to the increase in SOC.

Palavras-chave : pine and sacred fir forests; Mexican National Parks; biosphere reserve; forest soils.

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