When these soils are saturated with water, bacteria break down nitrate, and the nitrogen is released into the atmosphere as nitrogen gas. Heavy and prolonged periods of rainfall can result in nitrogen losses severe enough to require additional nitrogen applications to correct the problem. All sources of nitrogen are considered equal in their ability to provide nitrogen to cotton. No one form or source of nitrogen is superior to another if all are applied correctly. Base choices on price, availability, and ease of application.
Solid urea requires special consideration when applications are made to cotton.
If dry urea is applied to the soil surface in hot, dry weather, the rate of nitrogen loss can be high unless it is incorporated into the soil by tillage, rainfall, or irrigation within 2-3 days. Losses of over 30 percent in these situations are more common. Some growers apply nitrogen in split applications. The decision to use split applications, as opposed to all preplant, should be based on the rate of nitrogen used and whether or not irrigation is possible. If you will use more than 100 pounds nitrogen per acre, you should split the rate because of the danger of salt damage.