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.