Peanut Cultivar Response to Calcium Amendment.

Peanut (Arachis hypogaea L.) is unique among row crops in that it produces subterranean fruit. In order to maximize yield and quality parameters, the developing fruit has a high calcium requirement in the top 0-3 inches of the soil surface. In the Southeastern U.S., the predominant peanut is the runner market-type, which is a medium seed sized peanut compared to Virginia market-type (large-seeded) and the Spanish and Valencia market-types (small-seeded). Calcium requirement for maximum yield and quality parameters increases as seed size increases. Over the past few years seven new runner-type peanut cultivars have been released for production in the Southeastern U.S., five of which have a significantly larger seed size than previously released cultivars. Experiments were implemented in Georgia and Alabama to determine if the current calcium amendment recommendations for runner-type cultivars are still sufficient for maximum yield and quality. Trials were conducted in crop years 2009 - 2011 at the University of Georgia’s Coastal Plain Experiment Station near Tifton, GA on a Tifton loamy sand and at Auburn University’s Wiregrass Research and Extension Center near Headland, AL on a Dothan loamy sand. Large-seeded runner-type cultivar ‘Georgia-06G’ was compared to ‘Georgia Green’, a small-seeded runner-type cultivar that was the dominant cultivar in the Southeast U.S. from 1996-2008. Calcium amendment treatments were 0, 500, 1,000, and 1,500 lbs ac-1 applied at initial bloom. Data collected included yield, percent total sound mature kernels, seed calcium content, and percent seed germination. Data analysis indicated there was no difference (p<0.05) in yield for Georgia-06G between the Ca soil amendment treatments of 0 and 500 lbs Ca ac-1 when the 0-3 inch soil Ca level was greater than 500 ac-1. Results indicate the current recommendation of 500 lbs ac-1 in the 0-3 inches of soil is sufficient for large-seeded runner-type peanut cultivars.