14 Illinois Natural History Survey Circular 56 



Fertilizer sliould be applied when grass blades are drv. 

 Immediately alter the fertilizer has been distril)uted, it 

 should be washed from the grass blades with a lawn sprinkler 

 or a spray nozzle on a hose. Fertilizer remaining on grass 

 blades that become wet following a light rain or the 

 formation of dew occasionally causes burning. 



The amounts of fertilizer by source materials that will supply 

 the required 6 pounds of nitrogen per 1,000 square feet 

 and can be safely used in surface applications are listed below 

 (select only one): 



Material Pounds per 1,000 sq. ft. 

 Urea 45-0-0 ]?, 



Ammonium nitrate 33.5-0-0 18 



Ammonium sulfate 21-0-0 29 



Fertilizers containing phosphorus and potassium should not 

 be broadcast or spread on the surface except at rates 

 recommended for lawn fertilization. Applying such fertil- 

 izers as 1 0- 1 0- 1 at the recommended rate for nitrogen of 

 6 pounds per 1,000 square feet may cause severe damage 

 to grass. Do not use nitrogen fertilizers that have gotten wet 

 and become lumpy or caked for surface application. 



Figure 5. Two types of spreaders used to apply fertilizer to lawns can also be 

 used to apply nitrogen fertilizers to the soil around trees. A kitchen scale and a 

 bucket help to ensure accurate application rates. 



