357-9 Confirming Calcium Fertilizer Recommendations for Large-Seeded Runner Peanuts.

See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: General Soil Fertility and Plant Nutrition: I
Wednesday, October 19, 2011: 10:20 AM
Henry Gonzalez Convention Center, Room 216A
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Glendon H. Harris Jr.1, John Beasley1, Julie A. Howe2 and Robert Florence3, (1)Crop and Soil Sciences Department, University of Georgia, Tifton, GA
(2)Agronomy and Soils, Auburn University, Auburn, AL
(3)Auburn University, Auburn University, AL
Recently there has been a shift from growing small- to large-seeded runner peanuts in Georgia and other states in the southeast. While it is well known that the larger the peanut seed the more important calcium nutrition is for yield and quality, current calcium fertilizer recommendations have come into question. A series of field experiments have been conducted in Georgia and Alabama starting in 2008, mainly to verify the current recommendations still hold for large-seeded runners. The current recommendation is that if there is less than 500 lb Ca/a in the pegging zone (top 4 inches; Mehlich 1 extractant) and/or a calcium to potassium ratio less than 3:1, then 1000 lb/a of gypsum (calcium sulfate) should be applied at early bloom. After at least 12 site years with pegging zone calcium levels ranging from 285 to 790 lb Ca/a, the current recommendations appear to be sufficient. Yield, grade, calcium in the seed and germination was measured in all studies. The small-seeded peanut cultivar used in the studies was Georgia Green and the large-seeded cultivar was Georgia 06G. In two studies in Georgia, three other large-seeded cultivars were also included. Gypsum rates of 0, 500, 1000 and 1500 lb/a were used in most of the studies (the 1500 lb/a rate was not used in some studies due to space limitations). Either USG 500 or AgriCal (FGD) gypsum was used in all the studies. Additional studies were conducted to compare other sources of calcium applied at bloomtime, including calcium chloride and calcium thisosulfate liquids applied by a method to simulate being injected into irrigation water. Finally, timing of application studies have also been initiated to verify the application time of early bloom is the most effective
See more from this Division: S04 Soil Fertility & Plant Nutrition
See more from this Session: General Soil Fertility and Plant Nutrition: I