1. electricity generation
The Sulfur Cycle
Atmospheric SO2
(CH3)2S
COS
*Additional S
Information
SO42- in
ocean
H2S
sulfofication
desulfofoication
(CH3)2S
H2S
precipitation
Archaeon reduction
Thermoplasmales
pH<3
weathering
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. Atmospheric SO2 S2- SO4 in rainfall Irrigation water Fertilizers
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
microbial
decomp
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
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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.
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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
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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.
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7. back to “More Information on Sulfur”
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
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8. back to “More Information on Sulfur”
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
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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.
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10. back to “More Information on Sulfur”
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.
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