Sulfur (S)

Form used by plants:

SO₄^2- (sulfate) 
Both solution- and adsorbed- sulfate are forms available for plant use.

Important functions:

• Required for synthesis of amino acids and proteins

• Involved in electron transport during photosynthesis

• Component of protoplasm

Ideal foliage range for apple leaves:

0.2-0.4% or 250-600 mg sulfate-S/kg 

(note: leaf S tests are typically NOT performed with most analytical services)

Crop requirements:

Similar to P or Mg, approximately 15-35 pounds per acre per year are taken up by the crop.

Ideal soil range:

• SO₄^2- (sulfate)

• low: < 2 ppm

• medium: 2-10 ppm

• sufficient: > 10 ppm

sulfate is relatively mobile in soils

Best indicators: 

Very little information exists about sulfur in orchard nutrition.  Immature shoot tip leaves are the preferred tissue for diagnosing S deficiency.  Sulfate-S concentrations of 100 ppm or less are associated with S deficiency.

Mobility in plant:

Not remobilized within plant

Deficiency symptoms:

Similar symptoms to N deficiency except younger leaves are affected first. 

Increased risk of S deficiencies on:

Coarse-textured soils that have low organic matter content, shallow soils or soils in which the topsoil has been removed by erosion.  When in the sulfate form (SO₄^2-), it may be readily lost via leaching through coarse-textured soils.

Excess problems/Interactions with other elements:

• Excess sulfate reduces molybdenum uptake

Updated July 13, 2004

Contact us: tfrec@wsu.edu 509-663-8181| Accessibility | Copyright | Policies
Tree Fruit Research & Extension Center, Washington State University,1100 N Western Ave., Wenatchee, WA, 98801 USA