Soon after emergence of the peanut crop, soil samples should be taken from the pegging zone, or the top three to four inches of soil, so that calcium needs can be determined.
Glen Harris, University of Georgia Extension soil fertility specialist, continues to advise producers about the need for more calcium on large-seeded runners and other questions that the change in varieties has generated.
In The Zone
“Placing soluble calcium in the pegging zone or the top three or four inches is the critical point,” Harris says.
He recommends on large-seeded runner varieties that the rate be at least 750 pounds per acre. When the pegging zone calcium is between 500 and 750 pounds per acre, Harris calls this a “grey area” where calcium applications may still be beneficial. On smaller-seeded runners, 500 pounds per acre is recommended.
Gypsum is the material to apply at pegging, as lime should have been applied weeks before planting.
Calcium chloride or calcium thiosulfate applied through center pivots is becoming an option more producers are exploring. Calcium applied through a center pivot is still considered a soil-applied calcium because of the amount of water used to put out the material.
Harris says, based on two years of research at the Stripling Irrigation Park near Camilla, Ga., calcium chloride and calcium thiosulfate applied through the center pivot to supply approximately 25 pounds per acre of highly soluble calcium during bloom did improve yield, calcium in the seed and germination compared to the untreated check.
However, these products do not increase the soil test calcium levels after harvest as much as gypsum. The best fit is when the pegging zone calcium levels are in that “grey area”of 500 to 750 pounds of calcium per acre. If pegging zone calcium level is below 500 pounds per acre, apply gypsum. PG