Research in Montana has shown that split applications of nitrogen does not significantly affect yields if the early season nitrogen application was adequate for the grain yield potential. Irrigated spring wheat grain protein can be increased by 0.5 to 2.0% with the application of late-season nitrogen when early-season nitrogen application is adequate. Research in 1988 showed no difference in yields between deep-banded fertilizer and top-dressing fertilizer. No more than 30 pounds of nitrogen should be applied with the seed when applying ammonium nitrate (34-0-0) or urea (46-0-0).
An on-going “Strip Till Study on Sugar Beets” at the United States Department of Agriculture (USDA), ARS, Northern Plains Agricultural Research Laboratory in Sidney, Montana uses two different methods of fertilizer application. Conventionally-tilled sugar beets had the fertilizer broadcast in the fall before fall conventional tillage operations were performed. In the strip till beets, the fertilizer was shanked into the tilled strips in the fall.
Prices for different nitrogen formulations are significantly different.
Prices of Nitrogen Formulations
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Type of Formulation
Percent Nitrogen
Cost/Ton
Cost/Pound
Ammonium nitrate
34-0-0
$366/ton
$.54/lb
Anhydrous ammonia
82-0-0
$521/ton
$.32/lb
Ammonium sulfate
21-0-0
$266/ton
$.63/lb
Urea
46-0-0
$362/ton
$.39/lb
UAN (Urea – Ammonium sulfate solution
28% N
$232
$.41/lb
Diammonium phosphate
18-46-0
$337/ton
$.26/lb
Source: NASS
The choice of nitrogen source should be based on cost, availability, necessary equipment needed, cropping system, and personal preference.