Nitrogen and Phosphorus Recalibration for Sunflower in North Dakota

Abstract

Sunflower is one of the most important annual crops grown for edible oil in the world and is grown in North Dakota and the northern Great Plains more than any other region in the United States. Sunflower production and sunflower itself has evolved significantly since commercial cultivation began in the 1970s. In order to properly update fertility requirements of nitrogen and phosphorus in the northern Great Plains to correspond to this evolution, sunflower yield and oil concentration response to nitrogen and phosphorus fertilizer was investigated based on a twoyear (2014-2015) study. Highly significant statistical relationships between sunflower yield and oil concentration were found with nitrogen fertilizer rate but were not found with phosphorus fertilizer rate. This indicates that nitrogen fertilizer application rates used for sunflower need to be determined by current documented responses and that phosphorus fertilizer may not be needed to produce optimal yield and oil concentration of sunflower.