ISSUE 5 JUNE 3, 1999
TOP DRESSING OPTIONS
Recent heavy rains are causing N shortages in emerging crops. In
the Valley, these areas will tend to
be in depressions where crops have, or will be replanted. In the interbeach area, low N may be found
in both depressions and sandy ridges. In the till plain and western North Dakota, low N may be found
on hill tops and long slopes.
There are several topdress options: for row crops, sidedressing, ammonia,
or liquid N products
are commonly accepted practice; for small grains the options are different, when N can not be applied
below the surface, the volatility of the fertilizer must be considered.
Ammonium nitrate is the least volatile option. The N in ammonium
sulfate can be volatile if soil Ph is
high. Both of these options are more expensive than urea and may not be readily available in most areas.
Urea is stocked most everywhere. Application timing is critical
because it requires rain with in
about 48 hours to avoid significant losses. 28% is a liquid option which is half urea and half ammonium
nitrate. It should be cut half and half with water. When cut, it is relatively safe to apply on standing wheat.
For small grains the N application should be made by the five leaf stage. Rates of 30-50 lb. N per acre are
usually sufficient to restore original N levels.
NDSU Extension Soil Specialist