Anthony Bly
Soils Field Specialist
There has been some talk about possible nitrogen shortages this spring. It appears that extreme winter conditions have slowed river barge deliveries and rail shipment delays due to higher shipping volumes of other products may be contributing to slower deliveries of nitrogen, especially urea. While most producers will be getting most of their nitrogen, some may have to use other options for application management. It is extremely hard to tell where shortages might occur until strong consumption applies stress on supply. If shortages occur in your area, don’t despair there are options.
Corn and wheat don’t require large amounts of nitrogen early in the growing season because uptake is related to plant dry matter accumulation and grain development. Iowa State University’s Extension publication no. 48 “How a Corn Plant Develops – figure 53” shows that 50% of the required N has not yet been taken up by the plant at the R1 growth stage (silking). Therefore, getting a portion of the nitrogen applied at planting and using top dress or side dress nitrogen applications for the balance of the N, has been shown to be very effective and efficient N management tools. Most N application timing experiments in the Great Plains have shown similar and even higher yields between comparisons with later applied N such as top dress and side dress. A long term corn N timing study in South Dakota has shown the side dress application to provide similar or even higher grain yield as well as a wheat N timing study in North Dakota.
Getting nitrogen to the plant in the form required by the plant, when the plant needs it is good for the environment by reducing the chances for entry into water systems. The International Plant Nutrition Institute (IPNI) along with several other organizations has developed the 4R’s for nutrient stewardship, which includes the Right source, Right Rate, Right Place and the Right Time.
Understanding crop nitrogen use and uptake is a huge part of knowing how the 4R’s for nutrient stewardship can be used for more efficient nutrient use.
If you find yourself with short nitrogen supplies at planting time this spring, don’t worry! Later season nitrogen applications have been shown to be very effective, efficient and better for the environment. Consult your agronomist to find out what services they can provide you to help you get all of your nitrogen applied and possibly at the same time introduce you to other methods for nitrogen application and management that you haven’t used on your operation in the past. This potential situation could be a positive learning experience!
Sources : SDSU