Are variations in heterotrophic soil respiration related to changes in substrate availability and microbial biomass carbon in the subtropical forests?
Faculty of Sciences. Biology
London :Nature Publishing Group
Engineering sciences. Technology
Scientific reports. - London, 2011, currens
, 11 p.
University of Antwerp
Soil temperature and moisture are widely-recognized controlling factors on heterotrophic soil respiration (R-h), although they often explain only a portion of R-h variability. How other soil physicochemical and microbial properties may contribute to R-h variability has been less studied. We conducted field measurements on R-h half-monthly and associated soil properties monthly for two years in four subtropical forests of southern China to assess influences of carbon availability and microbial properties on R-h. R-h in coniferous forest was significantly lower than that in the other three broadleaf species-dominated forests and exhibited obvious seasonal variations in the four forests (P < 0.05). Temperature was the primary factor influencing the seasonal variability of R-h while moisture was not in these humid subtropical forests. The quantity and decomposability of dissolved organic carbon (DOC) were significantly important to R-h variations, but the effect of DOC content on R-h was confounded with temperature, as revealed by partial mantel test. Microbial biomass carbon (MBC) was significantly related to R-h variations across forests during the warm season (P = 0.043). Our results suggest that DOC and MBC may be important when predicting R-h under some conditions, and highlight the complexity by mutual effects of them with environmental factors on R-h variations.