Role of Sulfur in Pome Fruit Production
Sulfur is a key component of amino acids, proteins and coenzymes. Thus, lack of sulfur will inhibit protein synthesis and reduce tree growth.
General Guidelines for Sulfur Application
Apples require sulfur at similar levels to that of phosphate and most soils contain sufficient to support good growth.
Problems with sulfur are rare. Inadequate supplies are only likely in orchards on leached soils with low organic matter.
Sulfur Deficiencies in Apples
Deficient trees exhibit chlorosis in younger leaves at the top of the plant. Leaves get progressively paler yellow.