Cotton

Sulfur mobility is limited in cotton. As a result, sulfur deficiency symptoms initially start out as a yellowing, chlorotic appearance in the upper leaves and leaf veins. A nitrogen deficiency can sometimes be confused with a sulfur deficiency because a lack of nitrogen or sulfur is characterized by the yellowing of leaves.

If a potassium deficiency occurs early in the growing season, it will start off in the lower canopy and then later spread throughout the plant. Late season potassium deficiencies mainly occur when the soil is unable to meet the potassium demands during boll development.

Pre-bloom symptoms affect the older leaves first. This includes a light green to gold mottling between leaf veins that then progresses from yellowing to browning and the eventual necrosis of leaf margins.