Student Name:

 

 

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To complete this test, you will need to have access to the Internet for a few questions, and you will also need to find a bag of fertilizer with a label and a price.

 

1.      Compare the relative characteristics of rotary sprinkler heads with spray heads.  (7 pts).

 

Characteristic	Rotary	Spray
Price per unit
Price per area
Precipitation rate
Vulnerability to corruption by wind
Optimum pressure range
Appropriateness for small landscapes
Appropriateness for large landscapes

2.      Turfgrass irrigation scheduling uses information from weather, soil, and the turf plant to determine and control when and how to irrigate.  The most effective irrigation control involves using direct "real-time" determinations, measurements and devices that are highly representative of the condition of needs of the turfgrass plant.  Sometimes, indirect estimation must be used, for example, when long-range calculations are made for water use permit applications to public agencies.

The following problem considers the intermediate situation, when we know the estimated daily evapotranspiration (ET) rate for St. Augustinegrass (see Table, below), and can measure the actual rainfall, and can guess that the available soil moisture reserve (the maximum possible water in the root zone available to the plant) is 25.4 mm or one inch.  You may need to complete this table.  (12 pts).
 

Month	ET (inches/month)	ET (mm/day)
January	2.0
February	2.5
March	3.4
April	4.2
May	5.2
June	4.3
July	4.8
August	4.8
September	3.9
October	3.4
November	2.5
December	1.9
Total

Based on this information and assumptions, how many times would one have had to irrigate a lawn of St. Augustinegrass in Fort Lauderdale, Florida, in July, 2003?  Show your work.

You can get Fort Lauderdale rainfall records at http://fawn.ifas.ufl.edu  To find daily total rain, click, "Archived weather data"and select "Report generator"  Make sure to click the right buttons for the Report type ("Daily summary"), location, date range, and variables.  Rain data is in cm (centimeters).  Show your work or turn in an electronic copy.  Hint:  You can use Microsoft Excel or any other spreadsheet program to make it very easy.  The concept is that
soil moisture today = soil moisture yesterday + rain + irrigation - ET
Soil moisture can never go below 0 nor above 1.

The following table should give you an idea how you might want set up your solution of the problem, but please try to use a spreadsheet rather than long hand.

 

Year	Month	Date	ET	Rain	Soil water (between 0 and 25.4 mm)	Irrigate?
2003	6	30			25.4 (start out at full capacity)
2003	7	1
2003	7	2
2003	7	3
2003	7	4
2003	7	5
2003	7	6
2003	7	7
2003	7	8
2003	7	9
2003	7	10
2003	7	11
2003	7	12
2003	7	13
2003	7	14
2003	7	15
2003	7	16
2003	7	17
2003	7	18
2003	7	19
2003	7	20
2003	7	21
2003	7	22
2003	7	23
2003	7	24
2003	7	25
2003	7	26
2003	7	27
2003	7	28
2003	7	29
2003	7	30
2003	7	31
Total Irrigation Events:

 

3.      Using the evapotranspiration figures from page 2, above, and rainfall records from http://fawn.ifas.ufl.edu what months of the year was there a net monthly deficit (rainfall - evapotranspiration)?  (Remember, the FAWN reports centimeters (cm), while the ET chart above reports inches).  (5 pts).