Abstract

RAMIREZ PALACIO, Álvaro Andrés  and  MORENO HURTADO, Flavio Humberto. MICROBIAL AND ROOT RESPIRATION IN SOILS OF TROPICAL PRIMARY AND SECONDARY FORESTS ( PORCE, COLOMBIA ). Rev. Fac. Nac. Agron. Medellín [online]. 2008, vol.61, n.1, pp.4381-4393. ISSN 0304-2847.

Soils are the largest carbon pool of terrestrial ecosystems as well as the largest source of atmospheric CO₂ through a process called soil respiration. The purpose of this study was to estimate the soil respiration rates and its components (root and microbial respiration), and to evaluate the control of environmental factors such as soil humidity and temperature on emission rates of CO₂ in primary (PF) and secondary forests (SF) of the Porce region (Colombia). CO₂ emissions from soils were measured on a monthly basis for one year, in 10 plots using a soil respiration chamber connected to an infrared gas analyzer. Average annual rates of respiration were 15,91 (0,71 s.e.) and 14,03 (0,75 s.e.) C t • ha^-1- • año^{- 1 in PF and SF, respectively.} Root respiration accounted for almost half of total soil respiration in both forest types. Seasonal variation of total respiration was mainly associated to differences in soil water content. Results suggest that soils of tropical forest, emit significant amounts of carbon to the atmosphere and environmental factors such as soil humidity and temperature, might have an important influence on emission rates. In this way, an increase of CO₂ emissions from soils of these ecosystems, in response to climate change potentially, has important implications in global carbon balance.

Keywords : Andean forests; soil organic carbon; soil carbon efflux; soil respiration; soil temperature; soil water content.

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