Why Use Gypsum

1
Why Use Gypsum?
2
Benefits of Gypsum

• Its a good source of sulfate (SO4-2), the
  plant-available form of sulfur
• Its a good source of relatively soluble calcium
• Its effective at reducing soluble aluminum
  levels in subsoils
• Its good at flocculating a sodic
  (sodium-affected) soil

3
What Gypsum Cannot Do

• Breaks Up Clay
• Every bag of gypsum states this!
• No research or experience supports this claim.
• Dont believe everything you read on a label!

4
Recent Gypsum Research

• Lots of research supports the beneficial uses of
  gypsum
• 500 million tons stockpiled in Fl Gulf states
  from P fertilizer production
• 30 million tons/yr from fertilizer production
• 1990s saw a new wave of research in the Southeast
  to document the beneficial use of waste gypsum

5
Use of Gypsum in the Humid Region of the U.S.

• reduces crusting of soil surface
• decreases soil loss (10t/A/yr to 2.5t/A/yr)
• reduces runoff (63 to 34)
• ameliorates subsoil aluminum
• better root penetration into subsoil
• plants better able to survive drought

6
Agricultural Nutrient Management Program

• Percentage of total root mass at various depths 1
  year after gypsum application (Georgia)

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What are the Reasons for These Results?

• high aluminum in subsoil replaced by calcium from
  gypsum
• roots now capable of exploring subsoil
• enhanced water and nutrient supply
• particularly important in droughty years

8
Gypsum A Beneficial Soil Amendment

• Use it for the right reasons
• calcium and sulfur source
• aggregate stabilizer
• replaces aluminum, even in subsoils
• Dont be fooled by claims made on the product
  label.
• it will not break up clay subsoils!