Fertilization and nutrient management trials in peanut

Peanut producers have numerous questions with regard to proper calcium fertilization. The majority of these research questions seek to better understand when and how to apply calcium. Frequently asked questions include: Are all gypsum sources the same and which is the most economical? When is the most effective time to apply gypsum? Would split applications of gypsum be more effective than a single application? Does gypsum release calcium fast enough during peak pod fill? Can calcium be lost from the pegging zone due to high rainfall events? Do liquid calcium applications to the soil supply adequate calcium? Are calcium applications effective when applied as a foliar spray? Can calcium applied through irrigation pivots supplement gypsum/lime applications? This research seeks to provide research data to quantitatively answer these questions for growers. The specific objectives are to evaluate sources of calcium alone or as supplemental treatments, to assess the effectiveness of gypsum applied at various growth stages. Research is organized into three year field studies for each objective. This is the third year for the calcium source and timing study. Various sources of calcium, including two types of gypsum, soluble calcium applied through a center pivot, and foliar applied calcium will be evaluated alone or as supplemental treatments. Timing will include gypsum applications at approximately 45, 75, and 105 days after planting, as well as split application. Field plots will be established with Georgia- 06G and Georgia Greener at irrigated and non-irrigated sites and evaluated for yield, grade, germination, and seed calcium. Leaching of calcium from the pegging zone, use of seed Ca as pre-season' indicator of seed quality and late season fertilization needs, and the economics of calcium fertilization will also be considered.