Soil respiration related to litterfall in the high-Andean forest bush (Pamplonita river basin, Colombia)

Soil respiration (SR) and litterfall (LF) were studied in a bush dominated by Hypericum phellos and Monochaetum strigosum in a High-Andean forest in northeastern Colombia. SR monthly samples were carried out between January and December 2006 while LF was collected between August and December 2006. The daytime soil respiration (DSR) was bimodal with peaks in May and September (177,65 - 172,73 mg CO(2)m(-2)h(-1)) and was exponentially related to mean air temperature (R-2=0,48; p=0,013) and relative humidity (R-2=0,40; p=0,028). The night soil respiration (NSR) was trimodal with peaks in October, August and May (268,87 - 181,49 - 162,79 mg CO2 m(-2)h(-1)). The yearly DSR and NSR rates were estimated between 35,14 - 39,28 g C m(-2) and 42,48 - 47,42 g C m(-2), respectively. Based on the bush area (9,1 ha), the release of soil organic carbon (SOC) was calculated between 3,08 and 3,72 Mg C year(-1) for the daytime and night periods. The monthly fluctuations of the mean air temperature and the detritus fall (Df) determined (R-2=0,66; p<0,001) the dynamics of the diurnal (DSR=77,94T(MEDIA)+36,45Df-1142,8) and nocturnal respirations (NSR=99,05T(MEDIA)+57,44Df-1470,3), suggesting that the respiration rates in 2005 were 50 % higher than those in 2006. The bush edaphic catabolism was not as depended on the weather variables as in the pastures.