145-14 Diversity and Abundance of Bacterial Sulfur-Oxidizers in Australian Cropping Soils, and Their Role in Oxidizing Elemental Sulfur.
See more from this Division: SSSA Division: Soil Biology & BiochemistrySee more from this Session: Soil Biology & Biochemistry: I
Soils amended with ES (1000 µg/g) and controls were incubated for 96 days under controlled environmental conditions. The oxidation rate of ES varied from 5.1 to 51.7 µg/cm2/d. soxB gene copies ranged from 2.8×106 to 1.1×108 copies at Day 8 in controls, and there was no significant change in soxB gene copies across incubation in controls. The abundance of soxB genes in amended soils at Day 48 or 96 were more than those at Day 8, though the increase was not always consistent across all soils. The results from cloning and sequencing showed that most of colonies were affiliated with α- and β-proteobacteria. The most significant correlation was observed between ES oxidation rate and log transformed soxB gene copy numbers in control soils at Day 8 (R2=0.73, P<0.01, n=10), indicating that the population size of S-oxidizers affects ES oxidation rates in soil. Multiple regression analysis showed that soil pH (water) and the log transformed soxB gene numbers explained 82% of the variation of ES oxidation rate (P<0.01, n=10). These results suggest that a combination of soil biological and chemical properties provides a promising predictive estimate of oxidation potential of ES in agricultural soils.
See more from this Session: Soil Biology & Biochemistry: I