Reevaluation of calcium source for runner-type peanut (Arachis hypogaea L.)

Calcium supplementation is vital to optimal peanut production. As peanut cultivars and Ca sources change over time, Ca requirement may subsequently change, but few studies have reevaluated effectiveness of different Ca sources using currently produced peanut varieties. To address this issue, field experiments were performed in 12 environments (i.e., site-years) in the southeastern United States with the following treatments: four solid Ca sources, including mined gypsum, flue gas desulfurized (FGD) gypsum, phosphogypsum, and lime and four liquid Ca sources, including CaCl2 solution, chelated CaCO3, CaS2O3 solution, and CaCO3 suspension. The effectiveness of various Ca sources was evaluated on peanut yield, total sound mature kernels (TSMK), seed Ca, germination, and soil Ca using two runner-type peanut cultivars, Georgia-06G and Georgia Greener. Results indicated that the three evaluated gypsum materials had similar effectiveness, and the mined gypsum was the most effective possibly due to its larger, more crystalline particle size. Lime remains an adequate Ca source for peanut provided that water from rainfall or irrigation does not limit its dissolution. Liquid Ca sources, as stand-alone treatments, were not as effective as solid Ca sources possibly due to their low Ca content and great leaching potential. This study provides helpful information for Ca nutrient management for peanut.