US EPA

624646 

Journal Article 

Effect of Repeated Applications of Elemental Sulfur on Microbial Population, Sulfate Concentration, and pH in Soils 

Zhihui, Y; Haneklaus, S; Singh, BR; Schnug, E 

2008 

Yes 

Communications in Soil Science and Plant Analysis
ISSN: 0010-3624
EISSN: 1532-2416 

39 

1/2 

124-140 

Though there exists a wide spectrum of sulfur-oxidizing microorganisms in soils, the oxidation rate of soil-applied elemental sulfur (S0) is regularly limited because of a restricted population size. An incubation experiment was conducted to determine the effect of repeated S0 applications on different microbial populations, sulphate (SO42-)-S concentration, and soil pH. Elemental sulfur was applied repeatedly at a rate of 15 mg S g-1 soil in a 15-day interval cycle of 7 times. After each cycle, 7.5 mg lime (CaCO3) g-1 soil was applied to adjust the soil pH to an optimum range. Soil pH and 0.025 M potassium chloride (KCl)-extractable SO42--S were determined every 3 days. The population of Thiobacillus spp. and aerobic heterotrophic sulfur-oxidizing bacteria were counted 3 and 15 days after each S0 application. The results showed that the soil pH decreased rapidly from an initial value of 7.6 to 5.3, 15 days after the first S0 application. Lime applications successfully counterbalanced the acidifying effect of S0 oxidation, and soil pH values were maintained in the optimum range with a pH of about 6.4. The 0.025 M KCl-extractable SO42--S content increased with repeated applications of S0, showing a maximum value of 3,800 mg S kg-1 soil after the sixth S0 application. Thereafter, the SO42--S concentration decreased significantly. The Thiobacillus spp.count increased consistently with repeated S0 applications. The number of Thiobacillus spp. at the first application of S0 was significantly lower than the count after all other applications. A maximum Thiobacillus spp. count of 1.0 · 108 g-1 soil was observed after the seventh application of S0. The fastest S0 oxidation rate was found after the second application of S0. The population of aerobic heterotrophic sulfur-oxidizing bacteria increased also with repeated S0 applications, showing a maximum count of 5.0 · 104 g-1 soil after the fourth S0 application. Thereafter, the population declined steadily.... [ABSTRACT FROM AUTHOR] Copyright of Communications in Soil Science & Plant Analysis is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts) 

MICROBIAL populations; LAND capability for agriculture; MICROORGANISMS; PROKARYOTES; SOIL acidity; SULFUR; SULFATES; POTASSIUM chloride; THIOBACILLUS; Aerobic heterotrophic sulfur-oxidizing bacteria; elemental sulfur; priming effect; soil pH; Thiobacillus spp; Thiobacillus spp.