It's certainly no secret that corn planting is off to a late start this spring. When planting is delayed, it's important to get certain jobs done first when it is dry enough to be "in the field".

A good example is fertilizing. When it is dry enough, plant rather than apply preplant fertilizer. The reduction in yield potential due to delayed planting is far more important than the benefit of applying nitrogen before planting.

There is generally no yield loss in corn if sidedressing nitrogen is delayed up to the 4- to 5-leaf stage. This is due to most soils being able to supply ample amounts of nitrogen relative to the requirements of young corn plants.

With sidedressed nitrogen, increased efficiency of the nutrient is possible since it is being applied closer to the time plants will use it.

All common nitrogen fertilizers can be sidedressed. However, the order of preference from most to least desirable, is (1) injected anhydrous ammonia or UAN solution between the rows, (2) broadcast of solid ammonium-containing fertilizers such as ammonium nitrate or ammonium sulfate, (3) broadcast urea, (4) dribble UAN solution between rows, and (5) broadcast UAN solution.

With surface application, it is necessary to incorporate the fertilizer by rain (or by irrigation) to move nitrogen into the root zone to avoid volatilization loss. With injection, apply nitrogen between the rows to reduce the potential for plant injury.

Every other row pattern is an option for injection and it does not negatively impact yield since every row will have nitrogen applied on one side or the other. With this method, the outside injectors should deliver half the rate since the injector will pass between those rows twice.

The above news column is adapted from an article in the May 2, 2008 Pest Management & Crop Development Bulletin, authored by Dr. Fabian Fernandez, Extension soil fertility specialist.