Resumo

YANEZ DIAZ, María Inés et al. Soil respiration in four land use systems. Rev. mex. de cienc. forestales [online]. 2017, vol.8, n.42, pp.123-149. ISSN 2007-1132.

Soil respiration (Sr), or carbon dioxide (CO2) emission, is considered to be the second most important factor in the flux of carbon. Land use change has altered the global carbon cycle; this can aggravate global warming. The objective was to evaluate CO2 efflux variation on a daily and a seasonal basis in Vertisol under four land use systems -thornscrub, grassland, agricultural and Eucalyptus spp. plantation-, through weekly measurements in morning and afternoon samplings during one year, using a portable EGM-4 analyzer; the soil temperature and soil moisture were also measured. The Sr for morning was 3.21 µmol CO2 m-2 s-1 (agricultural), 3.86 µmol CO2 m-2 s-1 (plantation), 4.61 µmol CO2 m-2 s-1 (grassland) and 6.17 µmol CO2 m-2 s-1 (thornscrub); the values of the afternoon Sr increased for all land use systems. Significant differences (P≤0.05) in land use and sampling time were determined. The soil temperature ranged between 12 °C and 35.4 °C, and the soil moisture, between 6.9 % and 47 %. In Vertisols, CO2 efflux varies according their use, being higher in afternoon and in correlation with the moisture. Scrubs and grassland systems, which are more common in the northeast Mexico, showed the highest values for Sr.

Palavras-chave : Global warming; CO₂ efflux; Tamaulipas thornscrub; soil respiration; land use systems; Vertisol.