CaTs as a Dual Nutrient Source-Acidifier for Combatting Citrus Greening

Optimizing pH Levels in Soil

High soil pH is a common problem in Florida citrus soils because of high alkalinity in irrigation water.  University of Florida research has shown that lowering soil pH is more critical for greening-affected citrus.  With greening, soil pH needs to be lowered to around 6 or even a little lower to optimize yields.  As a result, applying acidifying agents is a common practice for lowering soil pH to combat citrus greening.

Elemental sulfur and sulfuric acid are the traditional acidifiers used to lower the pH of citrus soils in Florida.  Compared with CaTs, elemental sulfur releases acidity much slower and with much less predictable timing and is not suitable for application in irrigation water.  Both elemental sulfur and sulfuric acid lower pH mainly near the soil surface (roughly the top three inches) and tend to over acidify near the soil surface when enough acid is applied to lower pH at lower depths.  In contrast, CaTs lowers soil pH in the top roughly 12 inches or more without over acidifying near the soil surface.  Sulfuric acid is highly corrosive and difficult to handle whereas CaTs is not.  Calcium nitrate provides soluble calcium but does not lower soil pH and, in fact, increases soil pH when applied as the primary nitrogen source during the primary growing season.