50 Ways - 4. Apply Nitrogen in the Spring

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50 Ways Farmers Can Protect Their Groundwater

Nitrogen

1. Set realistic yield goals
2. Test the soil
3. Credit other nitrogen sources
4. Apply nitrogen in the spring
5. Use nitrification inhibitors when effective

Scouting

6. Scout fields

Insecticides

7. Know the economic thresholds for insects
8. Consider insect-resistant crop varieties
9. Spot-treat insect infestations when possible
10. Know how tillage affects insects
11. Know how crop rotation affects insects
12. Adjust planting & harvesting dates to control insects
13. Conserve beneficial insects
14. Consider using biological insecticides

Herbicides

15. Know the economic thresholds for weeds
16. Fine-tune your weed program to reduce rates
17. Manage crops to compete aggressively with weeds
18. Don't increase herbicide rates with conservation tillage
19. Band herbicides and cultivate
20. Control weeds with cover crops

Pesticide Selection

21. Determine the organic-matter of your soil
22. Determine your soil's potential for leaching
23. Determine your pesticide's potential for leaching
24. Determine the soil-pesticide interaction rating
25. Consider other critical pesticide qualities

Pesticide application

26. Select the proper nozzle tips
27. Calibrate your sprayer
28. Consider direct injection
29. SPrevent backsiphoning

Pesticide disposal and storage

30. Rinse chemical containers thoroughly
31. Dispose of rinsed containers safely
32. Dispose of excess chemicals safely
33. Store agrichemicals safely
34. Prevent and clean up chemical spills
35. Construct a rinse pad

Site conditions, wells, and septic systems

36. Know your well site conditions
37. Locate your well away from contamination sources
38. Make sure your well is constructed properly
39. Seal abandoned wells
40. Make sure your septic system operates correctly

Water testing & treatment

41. Test your water routinely
42. Test your water for coliform bacteria & nitrate
43. Test you water for pesticides
44. Know the signs of contaminants in drinking water
45. Select effective water-treatment methods

46. Store livestock waste properly
47. Have old, underground fuel storage tanks removed
48. Dispose of other hazardous waste safely
49. Take precautions when irrigating
50. Take precautions when chemigating

4. Apply Nitrogen in the Spring
	Your best bet is to apply nitrogen as close as possible to when your crop needs it most. Fall application of nitrogen increases the loss of nitrogen through denitrification. It also gives nitrogen time to leach through the root zone and into groundwater or subsurface drainage tile. Researchers estimate that with fall application, nitrogen losses from denitrification and leaching can range from 10 to 20 percent on fine- and medium-textured soils, and 20 to 50 percent on coarse-textured soils. University of Illinois research has also shown that it can take 120 pounds of fall-applied nitrogen to produce the same yield increase as 100 pounds applied in the spring.
	The increased risk of leaching on sandy soil may call for sidedressing—applying nitrogen right before the peak demand of the plant. But timing is critical with sidedressing. The period in which corn takes up nitrogen most rapidly is from about three to twelve weeks after planting. If the weather is too wet and you have trouble getting application equipment on the field in time, the benefits of sidedressing are greatly reduced.
	If you irrigate your sandy soil, one option is to apply a small amount of nitrogen at planting time (30 to 40 pounds per acre), one-third of it through the irrigation system no later than two weeks after tasseling, and the remainder as a sidedress application before corn is 8 inches tall. If you do not irrigate, you can split your nitrogen applications by applying one-third preplant and the other two-thirds sidedress.