I was recently asked if a product applied at 100 or 200 pounds per acre that includes calcium (12.2%) is as effective as gypsum. Data are presented in the technical bulletin from yield trials but with limited information. The trials either did not have a non-treated control or data from the non-treated control are not presented.

Based on my experiences, and I have discussed this with other research/extension folks working with peanuts, the amount of calcium in this product at the rates applied would not adequately approach what gypsum delivers at suggested use rates in the pegging zone. One question is the yield data. Without a non-treated control, it is impossible to know if one can make a conclusion on whether or not environment conditions or other aspects of the trial were appropriate to compare the products. My point is that with peanut response to gypsum, the amount of native calcium in soil, soil pH, rainfall patterns and variety can make a difference in response. Without the non-treated control data included, one does not know if a similar response of this product and gypsum was because the products perform the same or the native fertility or environmental conditions were such that neither product actually made a difference in yield. Appropriate controls in experiments that are repeated and replicated are essential for discerning if a product has a positive, neutral or negative effect on peanut yield and quality.

Theoretically, a product applied at these rates with this percent of calcium would not provide adequate calcium for pegs and pods, especially Virginia market types.