COMPARING AGRICULTURAL GYPSUM WITH LIMESTONE AND DOLOMITE (PART 3)

 

 

AGRICULTURAL GYPSUM AND AGRICULTURAL LIMESTONE COMPARED

 
   

Agricultural Limestone

(also called agricultural lime, ag lime, biolime, garden lime, or simply “liming”)

 

Agricultural

Gypsum

 

Chemical names:

 

Calcium carbonate

Calcium magnesium carbonate

 

 

Calcium sulfate dihydrate

 

Chemical formulas:

 

 

CaCO3

(CaMg(CO3)2)2

 

 

CaSO4 H2O

 

Common names4 used in agriculture, and purity or % calcium carbonate equivalent (CCE):

Ground limestone

(up to 100% CCE)

 

Dolomite3

(80-110% CCE)

 

Gypsum

(up to 100% gypsum equivalent)

Uses in agriculture: 1. Raises pH of acidic soils (generally when pH  6) by increasing exchangeable calcium and neutralizing hydrogen ions.

 

2.  As a source of calcium and/or magnesium in low pH and low Ca and Mg areas.  Note: agricultural limestone is always 150 times less soluble than gypsum.

 

3.  May slightly improve water penetration in acidic soils (pH  6) but the improvement decreases as pH rises. No improvement at pH  7.

1.               1. Amends and reclaims soils high in destructive sodium and magnesium.

2.

2. Improves water penetration at the soil surface, and infiltration through the entire profile.

 

3. Is necessary when irrigation water and soils are low in total salts.

 

4. Counteracts acidity in subsurface soils.

 

5. An excellent fertilizer source for calcium and sulfur.

1  Dr. Arthur Wallace, former Professor of Plant Physiology at UCLA, founder of Wallace Laboratories, and one of the most respected Soil Scientists of the 20th century, listed forty benefits for using gypsum with agricultural soils.  http://us.wlabs com/

2  dolomite can have a CCE greater than 100 percent since each molecule of magnesium carbonate is lighter than calcium carbonate

3 note: the proper name for dolomite is “dolomite (or dolomitic) limestone”

4 other less commonly used liming materials include sugar beet lime, hydrated lime, burned lime, shell meal, calcium silicate, power plant ash, and cement kiln dust