Impact of elemental sulfur fertilization on agricultural soils. II. Effects on sulfur-oxidizing populations and oxidation rates

Abstract

Effects of elemental sulfur fertilization on sulfur-oxidizing populations, rhodanese activity, total sulfur content and sulfur oxidation rates in the 0-15 cm zone of 2 Grey Luvisolic soils were assessed. Heterotrophic sulfur oxidizers were the most abundant sulfur oxidizers detected in both soils. Elemental sulfur fertilization caused an increase in populations of autotrophic thiosulfate-oxidizing microorganisms, and a 3-fold increase in rhodanese and sulfur-oxidizing activity in a Waitville soil. Sulfur fertilization did not stimulate autotrophic thiosulfate oxidizers in a Loon River soil and the greatest increase in rhodanese and sulfur oxidation rates was only 31%. The response to sulfur application was biphasic, however, and subsequent additions of sulfur fertilizer resulted in a decline in oxidation rates. -from Authors