Student Name:

 

 

__________________________________________________

 

 

 

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).

 


Year

Month

ET (mm)

Rain (mm)

Surplus or deficit for month

2003

1

 

 

 

2003

2

 

 

 

2003

3

 

 

 

2003

4

 

 

 

2003

5

 

 

 

2003

6

 

 

 

2003

7

 

 

 

2003

8

 

 

 

2003

9

 

 

 

2003

10

 

 

 

2003

11

 

 

 

2003

12

 

 

 

 

Total

 

 

 



4.      Why is the net monthly deficit not too meaningful for irrigation programming?  (5 pts).

5.      The Superintendent of Parks must have received a competing proposal to install a sprinkler system for Harmony Lake Park.  She emailed you, "Please list the major quality characteristics of your design.  We appreciate all the work you've done for us in the past, but because of the size of this contract, I have to present it to the City Commission at 7:30 pm tonight.  I need 5 bullet points about what's good about your design."  You suspect that a competitor must have offered the City a lower price, but so far you must be in the running, or she wouldn't have thanked you for your past work.

Respond to the Superintendent based on your knowledge of irrigation systems by providing 5 quality characteristics specific to your design.  (5 pts).

















In case that's not good enough, what can you offer as a warranty or assurance that the City of Harmony Lake will not be disappointed in choosing you?

6.      Sometimes it is desirable to amend a soil to improve the drainage and aeration of the root zone.  Take a sandy clay soil, 50% clay and 50% sand, and add sand to it until it is sandy loam, 20% clay and 80% sand.  How much sand would it take to amend a 1-foot depth of soil?  Show your work.  (5 pts).



 

 

 

 

 

 

7.      Compare and contrast the terms infiltration, percolation, leaching, runoff.  (5 pts).

8.      What are the main problems in using too small a pipe size?  (2 pts).










9.      How and why does turfgrass irrigation requirement and mowing vary in the shade compared with full direct sun?  (5 pts).

 

 


10.  List below the names and abbreviations of the 17 plant nutrient elements (16 are in our textbook, including 13 mineral elments; you can find element #17 on the Internet; it was added about 1988).  (5 pts).

11.  Find a fertilizer that lists as many as possible of these.  For those elements in the fertilizer and listed on the label, list the content by weight %, and what chemical it is derived from.  (You will also need to know the price.)  (10 pts).

 

Element name (spell out)

Element
(1 or 2-letter abbreviation)

Content (%)

Derived from

1

 

 

 

 

2

 

 

 

 

3

 

 

 

 

4

 

 

 

 

5

 

 

 

 

6

 

 

 

 

7

 

 

 

 

8

 

 

 

 

9

 

 

 

 

10

 

 

 

 

11

 

 

 

 

12

 

 

 

 

13

 

 

 

 

14

 

 

 

 

15

 

 

 

 

16

 

 

 

 

17

 

 

 

 

 

12.  For the fertilizer which you chose to represent, what is the unit price of nitrogen? (Show your work).  (2 pts).










13.  What is "soil reaction" and why is it so important to know, e.g., in the context of the elements that you just mentioned (give specific examples)?  (5 pts).










14.  “Organic” is a fertilizer that is commonly sold at the retail outlets.  Your neighbor asks, why don’t you use organic fertilizer instead of this dangerous chemical stuff?  What should you say to help educate your neighbor (remembering that he is going to continue to be your neighbor).  (2 pts).









15.  Compare C3 and C4 turfgrasses in terms of water use, climatic (temperature) adaptation, wear resistance (see article by Younger), moisture content, and anatomy.  Give examples of both C3 and C4. (5 pts).













16.  Why is it generally a very bad idea to mix spray heads and rotary heads on the same irrigation zone? (2 pts).



17.  You have assessed the coefficient of uniformity of an irrigation system, and it is only 55%, which is poor.  List 4 possible improvements that could be made to improve the system, based on possible causes for the problem.  (5 pts).

 

Possible cause of poor uniformity

Improvement needed

1

 

 

2

 

 

3

 

 

4

 

 

18.  Crudely sketch the design for a USGA specification green, labeling the layers, and describe at least three reasons for constructing such a green in such a way.  (5 pts).







 


Please read these carefully. Circle the one response (a, b, c, d, or e) that most correctly answers the question or completes the statement.  Each of the remaining four responses has a flaw with respect to the original statement, although containing some truth.  Multiple choice questions are worth 2 points each.

19.  How many 50-pound bags of urea 21-0-0 must be applied to 1 acre of turf at the rate of 1 pounds N per thousand square feet?

a.      50

b.      45

c.       20

d.      4.5

e.       2

20.  Which factor is the most important component in turfgrass evapotranspiration estimate?

a.      temperature

b.      relative humidity

c.       radiant energy

d.      the root zone

e.       wind

21.  Which factor is the hardest to estimate?

a.      temperature

b.      relative humidity

c.       radiant energy

d.      the root zone

e.       wind

22.  The fertilizer ammonium sulfate (21-0-0) is to be applied at 1 pound N per thousand square feet.  How many 50-pound bags are needed to treat a turf area of one acre?

a.      1

b.      2

c.       4

d.      8

23.  Bonus.  The following list of 10 learning objectives is for Master Gardeners.  Write a short, very clear paragraph explaining one of these learning objectives.  (10 pts).

Learning objective

Short description

Let the clips fall where they may

Lawn clippings contain nutrients that substitute for fertilizer

Zone irrigation to meet different needs of different plant groups

Because plants vary in rooting depth, they vary in soil moisture reserve to get them through a dry period.  Some plants get by on rain, others need irrigation.

Let your lawn tell you when to water or use a rain shut off device

South Florida lawns do best when watered no more than 30 times per year

Don't overwater

Overwatering encourages dollarweed and possibly some other weeds

Adapt to the shade if you can

Closed canopies transmit less than 6% of full direct sunlight.  All turfgrasses struggle to grow under trees.  Some varieties of St. Augustinegrasses have a little more shade tolerance than Floratam

Water uniformly

Non-uniform irrigation distribution causes waste

Mow at an appropriate height and frequency

Mowing too close encourages the growth of crabgrass and other weeds; also, it is important not to remove more than 1/3 of the foliage height

Don’t add phosphorus unless a soil test says so

In the C-11 West Basin of western Broward County, there is unexplained phosphorus contamination of the canals.  Make sure the landscape could not contribute to this.

Use an appropriate turf species and variety

Some grasses don't fit the conditions.

Keep your lawn reasonably lean

Overfertilization can make it very difficult to mow at a sufficient interval

 


Which learning objective was chosen?

 

1-paragraph explanation: