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SOIL MICROBIAL BIOMASS AND NITROGEN MINERALIZATION RATES ALONG AN ALTITUDINAL GRADIENT ON THE COFRE DE PEROTE VOLCANO (MEXICO): THE IMPORTANCE OF LANDSCAPE POSITION AND LAND USE
Author(s) -
Campos A. C.,
Etchevers J. B.,
Oleschko K. L.,
Hidalgo C. M.
Publication year - 2012
Publication title -
land degradation and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.403
H-Index - 81
eISSN - 1099-145X
pISSN - 1085-3278
DOI - 10.1002/ldr.2185
Subject(s) - mineralization (soil science) , nitrogen cycle , nitrification , deciduous , agronomy , soil respiration , biomass (ecology) , nitrogen , respiratory quotient , soil water , carbon cycle , environmental science , chemistry , ecology , ecosystem , biology , soil science , organic chemistry , biochemistry
A study was conducted to examine the responses of microbial activity and nitrogen (N) transformations along an altitudinal gradient. The gradient was divided into three parts. Three areas were sampled: upper part (UP): coniferous forest, corn field, and abandoned corn field; middle part (MP): tropical cloud forest, grassland, and corn field (COL); and lower part (LP): tropical deciduous forest and sugarcane. The results showed that soil microbial biomass carbon (C) and basal respiration were significantly higher in MP and UP than in LP, whereas the microbial quotient (C mic /C org ) was higher in LP and MP than in UP. The metabolic quotient ( q CO 2 ) was similar among gradient parts evaluated. Net N mineralization, ammonification, and nitrification rates were higher in UP than MP and LP. We found that in UP, the forest conversion to cropland resulted in no significant differences in microbial activity and N transformation rates between land uses. In MP, microbial biomass C, ammonification, and net N mineralization rates decreased significantly with conversion to cropland, but C mic /C org and nitrification were higher in COL. Basal respiration and q CO 2 were significantly lower in COL when compared with other land uses. In LP, lower microbial biomass C, C mic /C org , and nitrification rates but higher ammonification and net N mineralization rates were observed in tropical deciduous forest than in sugarcane. No significant differences in basal respiration and q CO 2 were found between uses of LP. Clearly, then, soil organic C is not equally accessible to the microbial community along the gradient studied. Copyright © 2012 John Wiley & Sons, Ltd.