Soil characteristics:
Low soil organic matter and low fertility (N = 13.3, K = 422, S = 29.3, Zn = 0.7 lbs/ac, OM = 2.5%, and pH = 8.3).

Treatments:
Manure and urea were applied, including a check plot (0 lbs N) at 45, 90, and 135 lbs N. Urea plots received 20 lbs of P (44 lbs P₂O₅), 10 lbs of S, and 1 lb of Zn.

Results and Observations:

1. Grain yields were higher from manure application than from urea. The treatments indicate that application of manure probably improved soil condition, which had a strong influence on grain yields.
2. When 45 lbs. N was applied as manure, yields and grain protein were not significantly different from the 90 and 135 lbs. manure N rates.
3. Economic analysis of the cost of manure application versus urea application showed it was better to apply N as urea than using manure (NDSU Carrington Research Extension Center Report of Agricultural Research to be published in January 2015).
4. The results indicated than profitability from urea N was mainly due to higher premiums from grain protein. Because the cost of applying 90 and 135 lbs. N as manure was higher than applying 45 lbs. N, but insignificant difference in protein content, it was more economical to apply manure at 45 lbs N. The likely reason for low protein compared to urea was availability, and that some of the manure N was immobilized at higher rates.
5. It is therefore likely that application of readily available N as a supplement to manure application would not only boost yields from improved soil physical and chemical properties, but would also enhance N uptake and protein content in the grain.     

Jasper M. Teboh
Soil Scientist