Management of nitrogen (N) continues to receive scrutiny as it relates to economic and environmental impact. The pursuit of higher yields by growers balanced against protecting the nutrient from environmental loss requires growers to utilize many tools and technologies. The 4 R’s of Nutrient Stewardship outline a template of considerations for growers to employ in constructing a nitrogen management program.
Traditionally, growers have employed practices such as delayed timing or split applications of N, nitrification or urease inhibitors, or slow release nitrogen. The turnover of organic N in the soil creates difficulty in estimating the appropriate N rate for any given field in any given year. This has led some farmers to use additional N to avoid deficiencies but this practice is expensive. Without our help, applying N at the correct rate (TPC – timing, placement, concentration) can be easier said than done!
Ammonium/Nitrate/Liquid Nitrogen Solution (UAN)
We know that Urea Ammonium Nitrate solution (UAN), 32% N is the principal source of all supplemental nitrogen. It can be added to suspension fertilizers in the fall, applied early in the spring, used as an herbicide carrier or a weed and feed fertilizer prior to planting, or as a post-emergence application.
Additionally, sulfur and potash can be added to a straight 32% nitrogen solution (the amount of nitrogen) to make various grades such as 20-0-4-2(S) in order to provide the grower with various amounts of additional sulfur and potassium. They can be applied 2×2 at planting, as a side-dress application, or through fertigation. When the uptake of plant nutrients has been reduced due to excessive moisture or compaction, side-dress application of analyses such as 20-04-4-2(S) makes the most sense.
Liquid Nitrogen (UAN Solution)
- Pre-plant dribble band
- Carrier for herbicides applied at pre-plant incorporation or pre-emerge.
- Post-applied by using the side-dress toolbar, Y-drop surface band, fertigation.
Blending Nitrogen Solution with Products
- Frequently blended with various crop protection herbicide products.
- Frequently blended with Ammonium thiosulfate solution (ATS).
- Occasionally blended with traditional liquid starter fertilizers at appropriate ratios.
Fall Nitrogen Fertilizer vs. Spring Nitrogen Fertilizer
- Nitrogen fertilizer is one of the most costly crop nutrients following seed
- It’s extremely important for ensuring top corn yields
- Excess N that doesn’t get taken up by the growing corn crop can lead to environmental concerns
This conversation links directly in with the 4 R’s of Nutrient Stewardship and their many benefits to your crops.
Why should farmers be concerned with the 4 R’s?
- They ensure a good return on your fertilizer and manure investments due to the high nutrient use efficiency
- If a lot of fertilizer nutrients are making it into the plant, that means those nutrients are not making it to unintended places, which means less environmental harm
Practices to keep nutrients from loss and tie-up:
- Cover crops
- Sub-surface placement of nitrogen fertilizer
- Edge-field strategies (e.g. buffer strips).
- Switch from fall to spring nitrogen sources
- Soil surface nitrate tests
- Side spaced nitrification inhibitors
Some of these practices will have a more immediate return on investment than others but they are all designed for ROI.