| The objective of this project was to determine the calcium requirements of modern varieties of runner-type peanuts. Few calcium studies had been conducted since Florunner was the predominant runner-type variety. The earlier studies had determined that applications of bloom gypsum, which is always recommended for larger-seeded Virginia-type peanuts and all peanuts grown for seed, is also recommended for Florunner when Mehlich-1 soil CA (calcium) was less than 200 mg/kg in Alabama and less than 250 mg/kg in Georgia and Florida. This experiment was conducted to determine whether modern runner-type varieties, which produce seeds of varying sizes, have calcium requirements different from Florunner and from one another.
The research was carried out in nine field experiments over three seasons at four sites (Headland, AL, Quincy, FL, Attapulgus, GA, and Tifton, GA). Four varieties were planted in replicated plots at each location. However, due to consistently changing variety recommendations, the varieties were not consistent over the course or locations of the experiment.
The varietal plots were split at first bloom; ½ received gypsum consistent with state-recommended levels and the other ½ did not. Plant and soil samples were analyzed at the Coastal Plain Experiment Station in Tifton, GA. All experiments were evaluated for pod yield and grade, and most experiments were also evaluated for calcium concentration and germination of the seed produced.
A summary of the field experiments shows that only one location had a soil Ca level under the threshold concentration, and which would benefit from gypsum. Yield, grade and germination at the site were also low, but largely due to a widespread CBR infection. Most modern commercial peanut fields have above-threshold levels of soil Ca, and yield and grade were not significantly increased by bloom gypsum applications in either Florunner or the modern varieties used in this study.
The general lack of interaction between variety and bloom gypsum application indicates no need for separate applications among these varieties. However, the data shows that grade, seed Ca and germination were increased by bloom gypsum, and that bloom gypsum applications should continue to be recommended for all varieties of peanuts grown for seed production.
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