Science and management of sulfur


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I shared this presentation with my Soil Fertility class in October 2011

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Science and management of sulfur

  1. 1. Sulfur has an atomic weight of 32.064 rare isotopes 33S, 34S, 35S and 36S can be used for tracing.
  2. 2. . . . sulfur is a devilish substance . . . Discharged from the bowels of the earth,by volcanoes or evil-smelling hot springs . . . Surely the effluent of Hell itself. – J.R. Postgate
  3. 3. Why is S important ?• Essential element required in relatively high concentrations by plants and animals• Essential component of 3 amino acids – cysteine, cystine, methionine• Disulfide bonds give structure to many proteins• Source of metabolic energy for many bacteria• Postive and negative environmental impacts – Macronutrient – Acid mine drainage, acidic deposition
  4. 4. Acid mine drainage!
  5. 5. Acidic deposition (aka acid rain) killed many of the trees in this forest Looks great butmay be devoid oflife if acidity has Monument getting released toxic levels of Al dissolved by acid rain
  6. 6. The S cycle is complex
  7. 7. Similarities with the N cycle Many oxidation statesMost of the S in soil is a component of SOM Biological transformations are important e.g., mineralization and immobilization Volatilization is a major loss pathway
  8. 8. S has lots of oxidation statesSulfides, -2 Sulfide ion S2-, bisulfide ion HS-, hydrogen sulfide H2S, carbon- bonded SPolysulfide, -1 Disulfide ion S22-, pyrite (FeS2)Elemental S S0Thiosulfate, -2 & +6 Thiosulfate ion S2O32-Sulfites, +4 Sulfite ion SO32-, sulfur dioxide SO2Sulfate, +6 Sulfate ion SO42-, sulfuric acid H2SO4
  9. 9. Only reduced forms of S (e.g., sulfides and elemental S) have acid forming potential. Rates of elemental sulfur required to decrease soil pH to a depth of 6 inches Application rate based on soil texture1Desired change in pH Sand Silt loam Clay ----------------------- lb S/A ---------------------- 8.5 to 6.5 370 730 1460 8.0 to 6.5 340 670 1340 7.5 to 6.5 300 600 1200 7.0 to 6.5 180 360 720 8.5 to 5.5 830 1660 3310 8.0 to 5.5 800 1600 3190 7.5 to 5.5 760 1530 3050 7.0 to 5.5 640 1290 25801 Assumptions—cation exchange capacity of the sandy loam, silt loam, and clay soil are 5, 10, and 20 meq/100 g, respectively; soils are not calcareous.
  10. 10. Differences with the N cycleVery little S in the earth’s atmosphere naturally(most of the S in the atmosphere today is anthropogenic)Weathering of rocks is the primary sourceMost global S in the earth’s crustSoil concentrations range from 10s to 1000s of ppm
  11. 11. Sulfur Forms in Soils• > 90% of total S in most soils is organic• Inorganic S – Sulfate dominates (SO42-) in aerobic soils – Sulfides (S-2, flooded conditions) – Elemental S – Thiosulfates (S2O32-) – Range in oxidation states (-2 to +6)
  12. 12. There are many strong smelling biogenic S compoundsCompound Formula Atmospheric Production concentration (Tg y-1)Hydrogen sulfide H 2S 0.2 – 1 ppb 16.5 – 70.6Sulfur dioxide SO2 0.2 – 5 ppb 15.0Carbon disulfide CS2 0.1 – 0.4 ppb 3.8 – 4.7Carbonyl sulfide COS 0.2 – 0.6 ppb 2.7 – 3.5Methyl mercaptan CH3SH added to natural gasEthyl mercaptan CH3CH2SHDimethyl sulfide CH3SCH3 58 ppt 39.6 – 45.4Dimethyl disulfide CH3SSCH3 1.3 – 3.4"smell of the sea"
  13. 13. Wet and dry S deposition is monitored throughout the US
  14. 14. Sulfur emissions in Wisconsin over the last 2 decades Why did S emissions decline?
  15. 15. The Cap and Trade Success Story "Cap and trade" programs harness market forces toachieve cost-effective environmental protection. Marketscan achieve superior environmental protection by givingbusinesses both flexibility and a direct financial incentive to find faster, cheaper and more innovative ways to reduce pollution. Cap and trade was designed, tested and proven in the United States, as a program within the 1990 Clean Air Act Amendments. The success of this program led The Economist magazine to crown it "probably the greatest green success story of the past decade." (July 6, 2002).
  16. 16. Is S a limiting nutrient ?
  17. 17. Sulfur deficiencies are increasingly common for 4 main reasons - Clean air standards have reduced SOx emissions from power plants and industry by > 50% in the last 2 decades - The S contents of fertilizers currently used in the US are far lower than those used historically.- Higher crop yields are removing higher amounts of S from soils as well as increasing the need for S.- Increased adoption of conservation tillage resulting in slower mineralization of organic S
  18. 18.
  19. 19. is no longer used in the US!
  20. 20. Relationship between tissue S and yieldSome species like brassicas and sugar beets have much higher S requirements
  21. 21. Typical crop uptake and removal values for S total uptake harvest residue crop yield lbs/ac lbs/ac lbs/ac cabbage 15 tons 71.0 33 38 canola 60 bu 68.0 20.4 47.6 alfalfa 8 tons 43.2 43.2 ----------- onion 30 tons 36.7 28.3 8.4 soybean 50 bu 35.0 23 12sugar beet 35 tons 29.8 15.8 14corn grain 180 bu 27.0 14.4 12.6sunflower 2500 lbs 21.3 6.25 15 wheat 80 bu 19.2 8 11.2Adapted from and other sources
  22. 22. IL Agronomy Handbook guidelines Soil test S (lbs/A) RATING 0 - 12 Very low 12 - 22 Low Response > 22 unlikely Correlation between yield increases and soil test S is low, indicating that soil test S does not reliably predict need for S. When soil test S levels are above 22 lbs /acre, it is very unlikely that a response to applied S will occur.When soil test S levels are below 22 lbs/acre, response to applied S is more likely (but not predictable).
  23. 23. The S guidelines in the IL AgronomyHandbook are derived from experiments conducted across Illinois in the late1970s that only identified 5 locations outof 82 where corn responded to added S. Hoeft, R.G., J.E. Sawyer, and R.M. Vanden Heuvel. 1985. Corn response to sulfur on Illinois soils. J. of Fert. Issues 2:95-104
  24. 24. Soil test S levels are declining In 2009, 13% of 2.5 million samples tested less than 12 lbs/ac Mehlich3 S(or equivalent) compared to only 4 percent testing below this level in 2005.Some of the highest frequencies of low S occurred in the western Corn Belt and central Great Plains.
  25. 25. is the crop most likely to respond to sulfur (S) application in Illinois. Organic matter is the primary source of sulfur in soils, so soils low in organic matter are more likely to be deficient than soils high in organic matter. S deficiency is most likely on sandy soils.
  26. 26. Sulfur Deficiency in Corn Unlike N, S is not readily Overall light green remobilized color, worse on newfrom older to leaves during rapid younger growth. plant parts.
  27. 27. Sulfur Deficiency in Wheat Overall light green color, worse on new leaves during rapid growth.
  28. 28. Important S concepts When S is deficient, plants tend to accumulate non-protein N, which raises the N/S ratio in the plant. A N/S ratio of 9:1 to 12:1 is especially important in forages that will be used for animal feed, so that the rumen microorganisms can effectively use the N. Grasses are more able to utilize sulfate (SO42-) thanlegumes, grasses will tend to crowd out the legumes in S deficient pastures. Rhizobia need S to fix N. Some plants, like mustard and onion, get their smell and taste from the presence of S compounds.
  29. 29. Sulfur is a key factor limiting the amount ofcorn by-products that can be fed to cattle. Sulfur levels of most corn by-products can range from 0.4 to 0.9% S on a dry matter basis. Some liquid by-products havebeen tested as high as 1.5 to 2% S. Sulfur is added during boththe wet and dry corn milling process, so the by-products containadditional levels above that concentrated from the original corn. Although it is based on limited research in cattle, the NRCrecommends a maximum tolerable level of 0.4% of the ration dry matter for sulfur in the ration. Using that recommendation as a guide the maximum level of corn by-products would range from 30% of dry matter intake at high sulfur levels to over 70% at low levels, based strictly on the S content
  30. 30. So how many lbs of ammonium sulfate should be applied if your goal is 10 lbs of S? So what can you apply if your soil needs S? Ammonium sulfate (21-0-0-?S)? Ammonium thiosulfate (12-0-0-26S) Potassium sulfate (0-0-50-18S) Sul-Po-Mag (0-0-22-11Mg-23S) Gypsum (0-0-0-23Ca-17S) Elemental S – 100% S (ES95, ES90, ES85) Animal manures – 0.4-0.7% S (on a dry basis)What is the sulfur content of ammonium sulfate? Chemical formula = (NH4)2SO4 Molecular weight = 132.1 g/mol Atomic weight of S = 32.1 g/mol 32.1/132.1*100 = 24% S
  31. 31. Example of an elemental S product ?
  32. 32. Elemental S products vary in S quantity and quality
  33. 33. ATS = 12-0-0-26S When mixed with other fluid fertilizers and applied as a concentrated band, ATS can enhance micronutrient availability, inhibit ureaseactivity, inhibit nitrification and improve availability of P ATS is a weak inhibitor compared to N-Serve and Agrotain
  34. 34. ATS = 12-0-0-26S When mixed with other fluid fertilizers and applied as a concentrated band, ATS canN loss (lbs/ac) enhance micronutrient availability, inhibit urease activity, inhibit nitrification and improve availability of P ATS is a weak inhibitor compared to N-Serve and Agrotain
  35. 35. Ca and S contents of gypsum samples Theoretical Synthetic Natural Cast Drywall analysis ofElement gypsum gypsum gypsum gypsum Ca(SO4)*2H2O (%) (%) (%) (%) (%)Calcium 23.3 23.0 19.1 22.4 21.9Sulfur 18.6 18.7 15.1 19.3 18.1
  36. 36. Wet flue gas desulfurizationGypsum
  37. 37.
  38. 38.
  39. 39. K-Mag = K2Mg2(SO4)3 = 23%S
  40. 40. We are looking for volunteers throughout Illinoisto participate in on-farm research to measure corn responseto sulfur fertilization. The better coverage of the state we canachieve, the greater our ability will be to predict where sulfur applications are most needed.We are especially interested in light-colored soils (less than2% organic matter, coarse texture, or both) and soils with aneroded phase. However, we would like to characterize sulfurresponse across Illinois, so we will also consider other more"traditional" soils. Fields that have received manure or sulfurapplications within the last five years will not be considered.Collaborators will follow a simple design applying 0 and 30 lbS/acre as a broadcast application in a uniform portion of the field. Three to eight replications are needed for each field.
  41. 41. Sulfur sources and application timingSulfur sources will be limited to ammonium sulfate (NH4)2SO4(21-0-0-24S); MicroEssentials sulfur 15% (13-33-0-15S); andelemental sulfur (0-0-0-90S). Elemental sulfur should only be used as a last resort because it often does not become fully available during the year of application. If the sulfur source contains other accompanying nutrients, the corresponding rates of those nutrients will need to beapplied to 0 lbs/ac S strips to avoid a differential response to nutrients other than sulfur. The preferred application time is spring, but if the only time available is fall, we can accommodate that. What is most important to us is to include as many locations as possible throughout the state.
  42. 42. Treatment optionsAmmonium sulfate (21-0-0-24S)For strips with 30 lb S/acre, apply 125 lb ammonium sulfate/acre. Forthe strip with 0 lb S/acre, apply 26 lb N/acre. This application is tobalance the N applied along with the S in the sulfur strip. Those 26 lb ofN/acre can be applied as either 57 lb urea/acre, 94 lb UAN (28%)/acre(8.7 gal/acre), or 82 lb UAN (32%)/acre (7.4 gal/acre). Do not useanhydrous ammonia because it would be difficult to apply only 32 lb ofproduct per acre.MicroEssentials MES15 (13-33-0-15S)For the strips with 30 lb S/acre, apply 200 lb MES15/acre. For the stripwith 0 lb S/acre, apply 145 lb DAP (18-46-0)/acre. This application is tobalance the N and P applied along with the S in the sulfur strip.Elemental sulfur (0-0-0-90S)For the strip with 30 lb S/acre, apply 33 lb elemental S/acre. For thestrip with 0 lb S/acre, there is no need to apply any product because theS source is not accompanied by any other nutrient.
  43. 43. The only data collaborators will beexpected to provide is the yield for each strip. This information can be collectedby yield monitor or from a weigh wagon. Volunteers will not be required to collectplant or soil samples but must be open to field visits by U of IL staff several times during the growing season.
  44. 44. Contact Dr. Fernandez if you wouldlike to be a S research collaborator!
  45. 45. Results from on-farm plots in 2010 Site 4 was an Onarga Site 10 was asandy loam in central IL Milford silt – response to added S loam in east- = 50 bu/ac central IL – response to added S = 21 bu/ac
  46. 46. Only one out of 6 IL research station sites observed any differences between S sources All fertilizer materials were spring appliedElemental S and gypsum can be good sources of S but require more time to become plant available
  47. 47.
  48. 48. TSI is committed to being the global advocate for sulphur, representing all stakeholders actively engaged in producing, buying, selling, handling,transporting, or adding value to sulphur.
  49. 49. The USA and Canada are global leaders in S production!
  50. 50. The price of S topped $600/t during the 3rdquarter of 2008 and then completely collapsed
  51. 51. Most S is recovered during gas and oil refining
  52. 52. Sulfuric acid is reacted with rock phosphate to produce phosphoric acid which is then used to make DAP, MAP and APP
  53. 53. If ammonium sulfate fertilizer costs $400/tonand we assume the N is worth $0.50/lb, what is the value of the S ($/lb)? AMS = 21-0-0-24S 0.21 * 2000 = 420 lbs of N * $0.50/lb = $210 $400 - $210 = $190 0.24*2000 = 480 lbs of S $190/480 lbs of S = $0.40/lb of S