Atmospheric SO 2

1. The Sulfur Cycle Atmospheric SO2 (CH3)2S COS *Additional S Information SO42- in ocean H2S sulfofication desulfofoication (CH3)2S H2S precipitation Archaeon reduction weathering Thermoplasmales pH<3 H2S H2S SO32-, SO42- FeS2 CaSO4 COS volatilization Biomass burning Fossil Fuel Combustion Volcanoes River sediment smelting/refining electricity generation Desulfuromanas Inorganic S S2- mineralization Photosynthetic anaerobic bacteria CO2 Soil solution SO42- light swamps,lakes estuaries

2. H2O3 Atmospheric SO2 SO4 in rainfall Irrigation water O3 Fertilizers dry deposition pH>7; less SO42- absorbed by plants wet deposition 2S + 3O2 + 2H2O 2H2SO4 microbial decomp microbial decomposition mineralization, redox reactions Soil solution SO42- immobilization Organic S Desulfovibrio, Desulfotomaculum mineralization Inorganic S H2S Leaching mineralization +O2 bacteria, fungi, algae, plants Thiobacillus, Beggiatoa, Chlorobium, Cromatium Beggiatoa Desulfuromanas S2- Authors: Xin Li, Dale Keahey, Jeremy Dennis, Michael Blazier, and Chris Stiegler

3. More Information on Sulfur General Concentrations Mobility in plant Effect of pH on availability Mobility in soil Interaction with other nutrients Deficiency symptoms Fertilizer sources Enzymes needing S Role of nutrient in plant and microbial growth Industrial uses References back to “The Sulfur Cycle”

4. General Facts • Sulfur is a pale yellow, non-metallic solid. • Name was derived from the Latin word for brimstone (“burning stone”), since it burns readily in air. • Elemental sulfur has been used since ancient times in religious ceremonies, to fumigate buildings, and for bleaching cloth. Also used agriculturally to lower the pH of soil. • During the Middle Ages, sulfur was one of the principal reagents used by alchemists in their search for the philosopher’s stone, believed to contain the secret of life. Modern chemistry has put sulfur to many other uses. • Large sedimentary deposits around the Gulf of Mexico and in Italy are extensively mined, as are volcanic deposits in Japan, Chile, and Indonesia. back to “More Information on Sulfur”

5. Form taken up by plants: SO42-, SO32- (low levels adsorbed through leaves) Mobility in plant: Yes Mobility in soil: Yes Deficiency symptoms: Leaves chlorotic (upper leaves), reduced plant growth, weak stems Enzymes needing sulfur and biological compounds containing sulfur: Coenzyme A, ferrodoxin, biotin, thiamine, glutathione, pyrophoshates, urease, and sulfotransferases back to “More Information on Sulfur”

6. Role of nutrient in plant and microbial growth • Sulfur atoms play important roles in the biochemistry of plants, animals, and microorganisms. • Synthesis of the S-containing amino acids cystein, cystine, and methionine; synthesis of other metabolites, including CoA, biotin, thiamine, and glutathione; main function in proteins is the formation of disulfide bonds between polypeptide chains; component of other S-containing substances, including S-adenosylmethionine, formylmethionine, lipoic acid, and sulfolipid; about 2% of the organic reduced sulfur in the plant is present in the water soluble thiol (-SH) fraction; vital part of ferredoxin; responsible for the characteristic taste and smell of plants in the mustard and onion families; enhances oil formation in flax and soybeans; sulfate can be utilized without reduction and incorporated into essential organic structures; reduced sulfur can be re-oxidized in plants. back to “More Information on Sulfur”

7. Concentration in plants: 0.1 and 0.5% of the dry wt. of plants Concentration in earth’s crust: 0.05% Effect of pH on availability: pH<6.5, AEC increases with decreasing pH Interaction with other nutrients: associated with salts and exchangeable cations, can be replaced by phosphorus on exchange sites; also interconnects with the calcium and nitrogen cycles in important ways back to “More Information on Sulfur”

8. Fertilizer Sources • Organic matter, ammonium bisulfite, ammonium nitrate-sulfate, ammonium phosphate-sulfate, ammonium polysulfide, ammonium sulfate, ammonium thiosulfate, ferrous sulfate, gypsum, magnesium sulfate, potassium sulfate, pyrites, potassium thiosulfate, potassium polysulfide, sulfuric acid (100%), sulfur, sulfur dioxide, single superphosphate, triple superphosphate, urea-sulfur, urea-sulfuric acid, and zinc sulfate back to “More Information on Sulfur”

9. Industrial Uses/Fun Facts • Sulfur is used to manufacture wood pulp, rubber, insecticides, fertilizers, and many medicines. • Hair, wool, albumen, mustard, garlic, horseradish, and cabbage all contain appreciable amounts of sulfur, as do many proteins. back to “More Information on Sulfur”

10. References • Hartmann, H.T., Kofranek, A.M., Rubatzky, V.E., Flocker, W.J. (1988). Plant Science. 2nd ed. Prentice Hall. Englewood Cliffs, NJ. • Marschner, H. (1995). Mineral Nutrition of Higher Plants. 2nd ed. Institute of Plant Nutrition Univ. Hohenheim. Academic Press. San Diego, CA. • Tisdale, S.L., Nelson, W.L., Beaton, J.D., and Havlin, J.L. (1993). Soil Fertility and Fertilizers. 5th ed. Macmillan Pub. Co. New York, NY. • Vaughan, D., Malcolm, R.E. (1985). Soil Organic Matter and Biological Activity. Martinus Nijhoff/Dr. W. Junk Publishers, Dordrecht. back to “More Information on Sulfur”