The purpose of this assignment is to practice rate conversions based on actual water spray and dry fertilizer applications which are conducted in class. Students will be able to revisit the fertilized plots to see the results.

A 4-nozzle boom spray unit was calibrated by spraying into 4 tubs for 20 seconds. The water in each tub was collected and measured in milliliters. The procedure was repeated at three pressures, 30, 40, and 50 psi (pounds per square inch). Assume that the boom spray unit is used to treat a field area, traveling at 3 miles per hour.

How many gallons per acre will be applied?

What information is missing from this problem?

The spacing of the nozzles - 12 inches

	Catchment in ml (milliliters), 20 second test
	Nozzle
Pressure	A	B	C	D	Average ml	Gallons per acre
30 psi	338	n/a	334	335
40 psi	370	372	372	370
50 psi*	217	217	217	217

* Changed to 10 second test because of the limited size of the source container.

A 3.5-foot drop-type spreader was used to apply fertilizer to a St. Augustinegrass turf area at three settings (there was also an unfertilized control treatment). This was repeated twice. Fertilizer was weighed before and after each plot was treated. Each plot was 7 feet X 20 feet, consisting of two parallel runs with the spreader.

What was the rate of application to each plot in pounds N / 1000 ft² ?

What essential information is missing from this problem?

The fertilizer analysis - 15-15-15

	North
Treatment	Low	High	Control	Medium	Medium	Control	Low	High
Setting	36	48	n/a	42	42	n/a	36	48
	Fertilizer amounts for each plot, in grams per plot
Before	10000	10000	n/a	5000	5000	n/a	5000	5000
After	9722	9208	n/a	4428	4462	n/a	4676	4108
Difference
	Application rates
Rate, pounds N / 1000 ft2

Depending on time, we may also attempt to compare the rate of fertilizer application based on differing ground speeds, and we may also attempt to compare the results of a centrifugal spreader with a drop spreader.

Data (fertilizer setting 42):

Fast: at 50 feet per 18.8 seconds walking speed, a total of 1.258 kg fertilizer was applied to two swaths 50 feet long and one 3.5 foot spreader width. (Walking times were 18.9 and 18.7 seconds for each of the two swaths).

Slow: at 50 feet per 35.05 seconds walking speed, a total of 1.524 kg fertilizer was applied to two swaths 50 feet long and one 3.5 foot spreader width. (Walking times were 34.9 and 35.2 seconds for each of the two swaths).