Why is landplaster used on peanuts?
To provide calcium without changing the pH. Peanuts don’t have the ability to translocate adequate calcium to the fruit so the pegs must touch calcium to form properly. Sandy soils don’t hold calcium so land plaster (gypsum) puts the calcium there when it is needed. Clay soils have the ability to hold calcium so landplaster isn’t needed on peanuts grown in clay soils.