Sulfur Fertilization: A Look into the Forgotten Nutrient

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Sulfur Fertilization A Look into the Forgotten
Nutrient
Bielinski M. Santos Camille E. Esmel Jack E.
Rechcigl
Gulf Coast REC
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Essential Plant Nutrients

• Macronutrients
• N, P, K.
• Ca, Mg, S.

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Essential Plant Nutrients

• Macronutrients
• N, P, K.
• Ca, Mg, S.
• Micronutrients
• Fe, Cu, Zn, Mo, Mn, B, Cl.

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Essential Plant Nutrients

• Macronutrients
• N, P, K.
• Ca, Mg, S.
• Micronutrients
• Fe, Cu, Zn, Mo, Mn, B, Cl.

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Science Stuff
Methionine
Amino acid chains form proteins.
Cysteine
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Importance and Sources of S
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Importance and Sources of S

• Applied indirectly with other fertilizers
• Super phosphate Rock phosphate and sulfuric
  acid.
• Ammonium sulfate.
• Rain and irrigation contributions.

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Contributions of S in the Atmosphere
Emissions of industrial gases Production of
SO2-.
SO2- ? H2SO4
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Regulation of Emissions
Diesel fuel with lower content of S
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Causes of Deficiencies

• Reduction of acid rain.
• Although acid rain is not desirable, it provided
  S to soils and plants.
• 1982 20-28 kg/ha.
• 2005 12-14 kg/ha.

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Causes of Deficiencies

• Cultivars with higher requirements.
• Use of high analysis fertilizers.
• Ammonium nitrate as main N source.
• pH gt 8 low organic matter content.
• Conditions of poor aeration.

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OM-S Relationship
Kamprath and Jones (1986).

• Mineralization occurs gradually.

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Deficiencies in Vegetables

• Often they can be confused with other nutrients.
• Lack of vigor.

• Symptoms appear in younger leaves.

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Sulfur in Vegetables

• Positive results
• Potato (Solanum tuberosum),
• Nabo roots (Brassica napus), broccoli (B.
  oleracea var. botrytis) and cabbage (B. oleracea
  var. capitata).
• Onion and garlic (Allium cepa, A. sativum).
• Green beans (Phaseolus vulgaris).

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Vegetable Production in FL
Source USDA, 2005
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Characterizing S Nutrition in Tomato

• To determine if an effect of S exists on tomato
  yield.
• To determine the sufficiency level of S for
  tomato.
• To determine the rate of S fertilization for
  tomato.
• To determine the influence of water and
  irrigation regime on the uptake of S.

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Field Studies

• Two studies at the Gulf Coast REC, Univ. de
  Florida.
• Deep Spodosols, lt2 MO pH 7.3.

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Sources of S

• Soil with lt30 ppm S.
• Ammonium Sulfate Nitrate (ASN 26 N, 14 S).
• Ammonium Nitrate (AN 34 N).
• Potassium Sulfate (PS 23 S, 55 K).

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• Raised beds are 28 in wide and 8 in tall.
• Fertilizer bands 12 in apart.

• Fumigated beds covered with mulch.
• Preplant fertilization only.
• Seepage irrigation.

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Treatments

• 1 lb/acre 1.135 kg/ha.
• Content of K was balanced with KCl where
  necessary.

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Foliar Concentration of S at 12 weeks

• 1 lb/acre 1.135 kg/ha.
• Content of K was balanced with KCl where
  necessary.

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Yield

• 1 t/acre 2.2 ton/ha.
• Content of K was balanced with KCl where
  necessary.

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Control AN alone
AN PS
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AN PS AN alone
ASN
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ASN AN alone
Control
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What do we do now?

• We are continuing to study
• The level of sufficiency and rates.
• Influence of irrigation method.
• Influence of irrigation water.
• Other vegetables
• Peppers, strawberry cucurbits.

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Thank you!
Questions?