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AG NOTES - ISSUE #569
Effective Nitrogen Management Strategies
NITROGEN MANAGEMENT WAS CRITICAL TO SUCCESSFUL SUGARBEET PRODUCTION SINCE THE CROP FIRST WAS GROWN IN THE RED RIVER Valley in 1918. Nitrogen management remains just as critical yet today. Many more tools are now available to fine tune your nitrogen management plan to maximize crop yield and quality, improve storage and increase factory efficiencies. Just as green manure crops and summer fallow disappeared as management options, fall applying 100% of your anticipated N needs may also have to change. You are strongly encouraged to carefully consider if change will benefit your farm business.
Utilize every option available to maximize your N fertilizer use efficiency. Precision N Management options include:
- Soil testing to a 4-foot deep
- Use of N stabilization and controlled release products
- Zone soil testing
- Variable rate N fertilization
- SPLIT N applications with use of sidedressing equipment - This practice is common in corn production why not beets?
Refining Your N Management Plan
- Obtain soil samples to an accurate 4' depth
- Use a local soil testing lab with a reputation for quality service
- Use satellite imagery or other reliable Precision Ag information to obtain soil samples by management zone
- Review past history of N application rates versus yield and quality on your farm
- Apply 65-75% of your anticipated N needs in the Fall of 2012
- Sidedress additional N as needed by the 8-leaf stage of the crop in the Spring of 2013
Table 1: Effect of Total Available N, 0-4 ft. on Recoverable Sugar and Gross Revenue Per Acre. 6 Year Average (2006-2011)
| Available N-Lbs. |
| Factor |
0-100 |
101-120 |
121-140 |
141-160 |
161+ |
| RSA (Lbs.) |
7986 |
8333 |
8059 |
8241 |
8143 |
| Rev/A ($) |
1330 |
1394 |
1351 |
1388 |
1359 |
Establish a target total available nitrogen level for each field. Consider soil test residual N, plus expected N mineralization from organic matter, plus added fertilizer. Then adjust the side-dress N rate up or down based on these factors.
How to Determine Amount of N to Sidedress in the Spring
| Factor |
Yield Impact |
Sidedress N Rate |
| Early Planting |
Increase |
Increase |
| Late Planting |
Decrease |
Decrease |
| Excellent Stand Establishment |
Increase |
Increase |
| Poor Stand Establishment |
Decrease |
Decrease |
| Low Stored Soil Water |
Decrease |
Decrease |
| Soils at Field Capacity in the Spring |
Increase |
Increase |
| Low Quality Beet History |
---------- |
Decrease |
| Low Yield History |
---------- |
Increase |
| Heavy Soil Type |
Decrease |
Increase |
| Light Soil Type |
Increase |
Decrease |
| High Organic Matter |
Increase |
Decrease |
| Low Organic Matter |
Decrease |
Increase |
Zone soil testing and variable rate fertilization increases yield, quality and revenue per acre. Using multiple targets for zones for total available nitrogen increases revenue per acre compared to using only a single nitrogen rate target.
Table 2: Effect of Soil Test Type on Recoverable Sugar Per Acre and Gross Revenue Per Acre. 6 Year Average (2006-2011)
| Soil Test Type |
RSA (Lbs.) |
Rev/A ($) |
| Not Tested |
7237 |
1182 |
| Conventional |
8034 |
1329 |
| Zone-Single Target |
8198 |
1367 |
| Zone-Multiple Target |
8342 |
1388 |
Contact Your Agriculturist for assistance with maintaining a highly effective Cercospora management program.
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