Santee-Cooper gypsum is used in three industries: Agriculture, cement industry — the largest user of the product, and in the manufacturing of wallboard. All the gypsum generated is sold to one of these customers, Carter explains.

In agriculture, virtually all the gypsum sold is used as land-plaster in the production of peanuts. In runner and Virginia type peanuts, calcium is by far the most critical nutrient for achieving high yields and grades.

Low levels of calcium causes several serious production problems, including unfilled pods (pops), pod rot disease, poor grades, darkened spots in the seed and poor germination.

Virginia-type peanut varieties are less able to take up adequate calcium than runner and Spanish types. This may simply be a matter of pod size, since there is less surface area on larger pods per unit weight of nut.

(As newer peanut varieties have come on the market, seed size has increased and this has changed the thinking on calcium requirements for the crop. For that information, visit

For runner peanuts, the critical soil test level is 600 pounds of calcium per acre, but on Virginia type peanuts, yield and grade response occurs even at a soil test of 1,000 pounds of calcium per acre.

In 2012, contracts for Virginia type peanuts have been for $700 per ton, highest in the post-peanut program era. Capitalizing on the high prices of 2012 will be a primary goal of all peanut growers, because the temporary shortage and subsequent high prices, will likely encourage over-production and bring prices back down in 2013.

Getting calcium on the soil is critical to both yield and quality. Some of the newer varieties like GA 08V, Bailey and Sugg have high yield potential — up to 7,000 pounds per acre — but require a high level of calcium in the soil to allow for pod-fill on these high-yielding plants.

The 70 million tons of gypsum generated by Santee-Cooper won’t be enough to meet the needs of South Carolina’s peanut farmers, but it will come close.

In future years, if growth in peanut acreage continues to climb and cost of production of synthetic gypsum continues to climb, the price for calcium, regardless of the source is likely to increase.

Gypsum is a naturally occurring mineral in many parts of the United States and the world. Gypsum is also often available as a by-product material.

Gypsum is hydrated calcium sulfate. The chemical name of gypsum is calcium sulfate dihydrate. Pure gypsum contains 23.28 percent calcium (Ca) and 18.62 percent sulfur (S) in the readily available sulfate form (SO4).