Calculating how much fertilizer to add to an area:

STEP 1: Desired rate in lbs nitrogen (N)/1,000 sq.ft / % nutrient  (as a decimal) = fertilizer needed per 1,000 sq.ft.

STEP 2: Total fertilizer needed / 1,000 sq.ft. x area in sq.ft = lbs fertilizer needed for the area

For example, to fertilize a lawn area 50 x 100 ft at a rate of 1 lb N/1,000 sq.ft. with a 18-3-18 fertilizer, the following calculation is required:

1 / 0.18 = 5.5 lbs fertilizer product/1,000 sq.ft

5.5 / 1000 x 5,000 (area) =  27.5 lbs total fertilizer needed

1.  How much fertilizer product is needed to apply 1 lbs N/1,000 sq.ft.  to a soccer field area 80,000 sq.ft with a10-2-8 organic fertilizer

Answer in lbs

2.  How much fertilizer product is needed to apply 1 lbs N/1,000 sq.ft. to a soccer field area 80,000 sq.ft  with a22-3-11 synthetic fertilizer

Answer in lbs

3. How many 50lb bags of organic fertilizer are needed?

4. How many 50lb bags of synthetic fertilizer are needed?

5. If the organic fertilizer costs $26.00 per bag, how much does this fertilizer application cost?

6. If the synthetic fertilizer costs $15.00 per bag, how much does this fertilizer application cost?

7. Which fertilizer do you believe is more environmentally friendly and which is the most economical?

PART 2

Using Google planimeter www.acme.com/planimeter  find Columbus Crew SC’s field at Mapfre Stadium (I suggest you use the satellite viewing option, rather than map option).

1. Calculate the area of the field (all green space inside the stadium) Write the answer in sq.ft.

1. Using the methods from Part 1, how many bags of organic10-2-8 fertilizer are needed if applied at 0.5lbs N/1,000 sq.ft.?

1. How many bags of synthetic 18-0-18 fertilizer are needed for the same rate?