Split Nitrogen Applications on Corn

Experiment Info

Planted 5/10/2011
Variety DeKalb 53-78
Population 32,000
Previous Crop corn
Plot Size 15′ x 210′
Replications 4
N Broadcast 5/13/2011
Sidedress 6/15/2011
Drop Nozzle 6/30/2011
Harvested 10/31/2011

Soil Test Values (ppm)

pH 7.4
CEC 13.8
%OM 2.7
Bicarb 12
K 113
S 7
%K 2.1
%Mg 24.0
%Ca 73.7
%H 0
%Na 0.2
Zn 1.0
Mn 2
B 0.7

Objective:

Evaluate single vs. split applications of 28% UAN + eNhance for effect on corn yield.

Previous testing at the NCRS with application timing of nitrogen on corn has surprisingly shown similar yields regardless of method of application. However such testing was with High NRG-N and has not been thoroughly tested with 28% UAN + eNhance. (Recall that eNhance is added to 28% UAN at a rate of 2 gallons per ton.) This experiment compared fi ve different application timings for 45 gal/A of 28% + eNhance to corn following corn: 1) all Broadcast Pre-emergence (after planting); 2) all Sidedress; 3) 15 gal/A 2×2 (with planter) and 30 gal/A Pre-emergence; 4) 15 gal/A 2×2; 15 gal/A Pre-emergence; 15 gal/A Sidedress; and 5) 15 gal/A 2×2; 10 gal/A Pre-emergence; 15 gal/A Sidedress; 5 gal/A through Drop nozzles. A comparison treatment of 55 gal/A 28% UAN applied Pre-emergence was also applied. Yield results appear in the following chart.

Conclusions:

  • These results were somewhat unexpected as it shows that single applications are better than multiple applications.
  • This was corn after corn and there was residue, but the N did not get tied up from the single surface application. However, the 45 gal/A of 28% with eNhance did out yield the 55 gal/A rate of 28% without it.
  • Despite the apparent yield differences, the yields were not statistically different at the (0.1) level, which does confirm earlier findings that different methods of application result in similar yield.

Split Nitrogen Applications on Corn