Effect of Calcium Source, Rate, and Time of Application on Soil Calcium Level and Yield of Peanuts (Arachis hypogaea L.)1

Abstract

Abstract Studies were conducted both in the laboratory and in the field to determine the relative availability of calcium from several calcium sulfate materials, and their effect on the yield and grade of peanuts. The initial rate of Ca leaching in the laboratory study was greatest for Phosphogypsum, medium for the regular finely-ground anhydrite landplaster and least for the granular anhydrite landplaster. With continued leaching the Ca level extracted after applying the three sources became similar. Some differences were noted in the rate of leaching that were associated with soil properties, primarily cation exchange capacity. In the field, the materials were applied early in the season and at flowering. No consistent difference existed among the sources in soil test Ca or SO4-S levels during the growing period. These levels were lower, however, late in the season if the materials had been applied early rather than at flowering. Similar conclusions were reached when evaluating the temporary pH drop caused by applying the Ca sources. Yield and grade of peanuts were affected by applying the Ca sources in one field study. The positive response was similar from the three materials which, in this particular study, were applied only at flowering.