How much fertilizer is applied each year on lawns throughout the united states?

where does the nitrogen for this fertilizer come from?

1.8 pounds  of Nitrogen per year; (based on 1000 square feet per application) for cool season grasses.

Explanation:

The above application shows  an average of 0.9 pounds of inorganic and organic  nitrogen per 1000 square feet per application . Therefore not more than 0.9 pounds of nitrogen will be needed  per application.And for a whole year 1.8 pounds of Nitrogen per year will be needed.

This calculation was based on 1000 per square.But most lawn are not 1000 per square, therefore calculation can be done using the 1000 per squares as the  reference point .

AMMONIA and its solutions, AMMONIUM NITRATE AND UREA  (which is organic source)are the sources of this Nitrogen.

Urea is non -explosive in nature and solid. However, ammonia and ammonium Nitrate are both explosive.

the real answer is b. scintillation counter