There are many options for nitrogen placement when it comes to fertilizing a corn crop. In this blog post, we’ll take a look at the research we’ve done to optimize nitrogen application to corn. We’ve researched multiple fertilizer application methods and conducted extensive research to help farmers optimize their nitrogen fertilizer for corn. We’ve updated this post in 2022 to include more research and compare additional methods to apply nitrogen to corn.
Experiment Info
| Planted | 5-25-2014 |
| Harvest | 10/30/2014 |
| Yield Goal | 175 bu/A |
| Target Fert. | 193-70-8 |
| Variety | DKC 49-29 RIB |
| Population | 32,000 |
| Row Width | 30″ |
| Prev. Crop | Soybeans |
| Plot Size | 15 x 265 |
| Replications | 4 |
| Sidedress | 6/23/2014 |
Soil Test Values (ppm)
| pH | 6.1 |
| CEC | 14.5 |
| %OM | 2.5 |
| Bray P1 | 10 |
| Bicarb P | – |
| K | 131 |
| S | 11 |
| %K | 2.6 |
| %Mg | 14.4 |
| %Ca | 69.1 |
| %H | 13.9 |
| Zn | 1.4 |
| Mn | 10 |
| B | 0.6 |
Sidedress Nitrogen Fertilizer for Corn
In this experiment, we evaluated the yield response of different nitrogen sources and additives applied sidedress on corn.
The nitrogen market has many options for liquid fertilizer sources for sidedressing corn. This experiment looks at High NRG-N in comparison to 28% UAN, sulfur additives: eNhance, accesS and ammonium thiosulfate (ATS) and a competitors additive Instinct. Each product was applied at recommended rates to provide 193 lbs of nitrogen per acre to meet the yield goal of 175 bu/A corn. The three standard programs included 45 gal/A High NRG-N (70% rate), 51 gal/A 28% + eNhance (80% rate) and 64 gal/A 28% UAN. Sulfur additives accesS and ATS were added to the full rate of 28% UAN to provide 20 pounds of sulfur per acre. Additionally a 100% rate of 28% + eNhance was applied at the same rate as 28% UAN. All treatments received the same planter application of Pro-Germinator, Sure-K and Micro 500. Yields appear on the chart below.
Conclusions:
- The three standard programs, High NRG-N, 28% + eNhance and 28% UAN, applied at recommended rates yielded above the 175 bu/A yield goal, all reaching around 184 bu/A. Although High NRG-N and 28% + eNhance applied fewer gallons per acre.
- The addition of eNhance at 2 gallons per ton of 28% UAN increased corn yield by nearly 10 bu/A.
- Competitors products ATS and Instinct increased corn yield over 28% UAN alone, adding over 6 bu/A more.
- Highest yield was achieved with the addition of 4 gal/A of accesS to 64 gal 28% UAN.
- All additives that included sulfur, significantly increased corn yield over the standard 28% UAN rate alone.
Comparing Multiple Application Methods
In this experiment, we used two nitrogen sources: High NRG-N and 28% + eNhance. Methods of application included: PRE emergence broadcast treatment, sidedress application 30 days after planting and a split application where 15 gallons per acre was applied 2×2 at planting with the remainder at sidedress. An additional treatment of 28% UAN applied PRE broadcast and was tested as a standard comparison. Yields appear on the chart below.
Conclusions:
- There was no significant difference in yield amongst methods of application for both of the nitrogen sources. Numerically, the sidedress applications yielded slightly higher than either the broadcast or split applications.
- At broadcast, 28% yielded slightly higher than High NRG-N but there was no significant difference between it and 28% + eNhance.
- The sidedress treatments showed no statistically significant difference in yield between the two nitrogen sources.
- There was no difference in nitrogen sources with the split applications. However, by using High NRG-N at plating and sidedressing with 28% UAN there was a yield increase. This warrants further testing in the future as there may be advantages to using two products with different nitrogen-release curves.
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Single vs Split Applications for Nitrogen Fertilizer on Corn
In this experiment, we set out to compare 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.
