The Nature of Yield Responses of Florunner Peanuts To Lime

The effectiveness of spring-applied agricultural limestone and topdressed gypsum as Ca sources for Florunner peanut (Arachis hypogaea L.) production was determined in 78 on-farm experiments in southeastern Alabama during 1972–1979. Dolomitic and calcine limestones were incorporated into the upper 10 cm of soil at a rate of 2.24 metric ton/ha, and gypsum (CaSO4 •2H2 O) was topdressed at early bloom at 560 kg/ha. Limestone and gypsum were essentially equal sources of Ca except on a Bonifay sand where gypsum was inferior. Lime applied in this manner apparently increased yield and grade because of its Ca content and not because it increased soil pH. Limestone disked-in just prior to planting did not need a Ca supplement in the form of top-dressed gypsum. Only one instance of Mg deficiency was identified, and that was on a low-Mg soil with very little clay in its profile.