Impact of Anhydrous Ammonia vs Urea on Spring Wheat Performance

B.S. Miller and D.L. Klinkebiel

The impact of anhydrous ammonia (AA) versus urea on grain yield and quality of spring wheat has been a common question by many producers. A trial conducted at the Carrington Center evaluated the impact of fall and spring-applied AA versus spring-applied urea on "2375" and "Kulm" spring wheat in 1993 and 1994, respectively. Each nitrogen source was applied at 0, 75, 100, 125, or 150 pounds per acre under dryland and irrigated conditions to evaluate the impact of fall and spring rainfall events on potential nitrogen leaching.

Impact of anhydrous ammonia vs urea on spring wheat performance.

Treatment

1993

1994

 

Grain Yield bu/ac

Fall AA

42.2

54.8

Spring AA

43.1

56.4

Spring Urea

39.2

57.9

Mean

41.5

56.4

LSD @0.05

1.9

1.6

 

Test Weight lbs/bu

Fall AA

55.6

57.6

Spring AA

55.9

57.3

Spring Urea

54.5

56.8

Mean

55.3

57.2

LSD @0.05

1.1

0.5

 

Protein %

Fall AA

13.64

14.01

Spring AA

13.33

13.99

Spring Urea

13.40

13.71

Mean

13.46

13.9

LSD @0.05

0.21

NS



In 1993, grain yield and test weight were similar between fall- and spring-applied AA but significantly greater than spring-applied urea, while greatest grain protein was achieved with fall-applied AA. In 1994, greatest spring wheat yield was achieved with spring-applied urea and spring-applied AA. Test weight was highest with fall- or spring-applied AA. Grain protein was similar across treatments in 1994.

As results indicate, the impact of nitrogen source and timing on wheat grain yield and protein is variable. Therefore, each producer must decide on the application procedure best suited for his or her operation taking into consideration equipment requirements, time constraints (fall vs spring application), fertilizer cost, and personal preference.

Affiliation of co-authors and non-CREC staff: D.L. Klinkebiel-former CREC associate agronomist.

 

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