Relationships of soil microbial biomass carbon and organic carbon with environmental parameters in mountainous soils of southwest China
2001
Piao, H.C. | Liu, G.S. | Wu, Y.Y. | Xu, W.B.
The relationships between microbial biomass C, organic C, and environmental parameters were studied in soils under corn (Zea mays. L) in the mountainous areas of southwest China. Three yellowish-red (Ultisols), yellow (Ultisols) and yellowish-brown (Alfisols) soils were relatively weathered, leached and impoverished, with most having a low input of aboveground corn residues. Seasonal changes in soil microbial C at 0-10 cm depth were significant at each sampling site, with the highest value (120 g C m(-2)) in winter, and lowest value in summer (21 g C m(-2)). Microbial biomass C was significantly and negatively correlated with site elevation and positively correlated with mean annual temperature. The seasonal change in microbial biomass C was significantly correlated with total soil organic C. The decline in microbial biomass C estimated as a percentage of the total soil organic C was negatively correlated with the elevation above sea level, ranging from 3.9+/-0.9% below 600 m to 1.4+/-0.5% above 1,500 m, suggesting higher turnover rates of soil microbial biomass C at warmer air temperatures. Temperature influenced the decomposition of organic C in soils mainly through its effects on microbial biomass C, and the microbial biomass C/organic C ratio appears to be a sensitive index of the change in organic matter content of soil.
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