5
Agronomy 365T
Exam 3 Spring 2008
Name
Exam Score: ____________
TA
Lab Day and Hour
Be sure to show all calculations so that you can receive partial credit for your work!
1) List the 8 plant essential micronutrients for plant growth Provide the complete name of the element (spelled correctly) and one form taken up by plants. Spelling and charge count! (8 points)
Form taken up by plant
Essential Nutrient including valence
1. ________________________ _____________
2. ________________________ _____________
3. ________________________ _____________
4. ________________________ _____________
5. ________________________ _____________
6. ________________________ _____________
7. ________________________ _____________
8. ________________________ _____________
2) What nutrient deficiencies are shown in the pictures projected. (3 points)
a) ______________________________________
b) ______________________________________
c) ______________________________________
3) Explain how the following are important to soil fertility:
(4 points)
a) Apatite
b) Feldspars, Muscovite, and Biotite
4) CEC Calculations - Use the following data for problems a through g:
Soil Test Report
pH Lime OM P K Mg Ca CEC % B.S.
Index (%) (-------------ppm----------------) (cmolc/kg) (%)
? 6.2 2.8 32 140 120 2000 ? ?
a) Calculate the CEC of this soil. (4 points) ____________
b) Calculate the % Base Saturation of this soil. (1 point) ____________
c) Calculate the pounds per acre of magnesium in this soil. (1 point)
(Hint : AFS = 2,000,000 lbs. and the atomic weight of Mg= 24g) ____________
d) What is the estimated pH of this soil? (1 point) ____________
e) Calculate the pounds per acre of phosphorus in this soil. (1 point) ____________
f) Is P at or above the critical level for turfgrass or wheat? (1 point) ___________
g) Is K at or above the critical level for corn and soybean production? ___________
[75 + (2.5 X CEC)] (1 point)
5) What are the two most likely micronutrients to be deficient in turfgrasses? (2 points)
6) Discuss the factors that influence potassium availability in soils. Include in your discussion terms such as “slowly available K”, unavailable K, and exchangeable K. Be complete! In addition, list one extractant that you used to measure “available” potassium and indicte how this extractant works to measure “available” potassium. (6 points)
7) Phosphorus in Soils
A. Label the four arrows shown on the diagram in Part B: (4 points)
1. _________________________ 3. _________________________
2. _________________________ 4. _________________________
B. Explain the chemistry of soil phosphorus in a Mollisol (from Indiana) for Boxes A and C shown below. List the forms of phosphorus found in each box, the relative amounts found in soil, and briefly explain how the four numbered processes affect availability of phosphorus to plants. Also, write the predominate available forms (Box B) of phosphorus (including valence) taken up by plants at pH 4.5 ____________and at pH 7.5 __________
(6 points)
8) For each of the micronutrients listed, give the information requested. (9 points)
Potential Soil Conditions Where List the Most List one
Deficiency Might Occur Susceptible Fertilizer Source
(2 conditions for each nutrient) Crop found in Indiana for each nutreint
Iron
Manganese
Molybdenum
9) Indicate under what conditions it can be advantageous to use a starter fertilizer when growing corn in Indiana. (2 points)
10) Briefly explain how each of these fertilizer materials is manufactured. Include the starting material(s) and the general process that produces the fertilizer. State which of the two processes involves the use of a pipe reactor. (4 points)
A. 0-44-0
B. 10-34-0
11) On the graph below, diagram the Build-up, Maintenance, and Drawdown portions of the Build-up and Maintenance philosophy of making fertilizer recommendations (Tri-State Fertilizer Recommendation Manual). Include in your diagram the shape of the curve (3 connected straight lines) and the three different regions of the diagram with appropriate labels: Build up, Maintenance, and Drawdown. Also, label the critical level. (4 points)
12) What is the primary function in the plant for each of these nutrients? (4 points)
Nutrient Primary Function in the Plant
Potassium _____________________________
Phosphorus _____________________________
13) Discuss the factors you must consider before taking tissues samples for plant analysis and idicated the best way to take these samples and send them to a lab for analyses. Also, discuss the importance of using plant analysis as part of a nutrient management plan. (4 points)
Multiple Choice Questions (2 point seach) – Record the best answer to each on the line provided.
_____1. If a fertilizer label reads 8-32-16, it contains:
A. 8% total N
B. 32 % water soluble P2O5
C. 16 % total K
D. All of the above
_____2. How many pounds of N would be supplied from 18-46-0 if it was used to supply 120 lb P2O5/A
A. 22 lb B. 31 lb C. 47 lb D. 261 lb E. 422 lb
_____3. 8-32-16 fertilizer would most likely have its source of potassium in which chemical
form:
A. K2O
B. P2O5
C. Dicalcium Phosphate
D. KCl
_____ 4. dy/dx = (A – y) C --- This equation is called
A. Liebig’s Law of the Minimum and represents growth as a function of nutrients present in the soil and relates how the nutrient in the lowest amount reduces rate of growth.
B. Mitscherlich’s Equation and represents the change in yield for a given change in growth factor (e.g. fertilizer input) --- with each additional input, change in yield is reduced.
C. Boomsma’s Law of Success representing how a student’s grade changes in proportion to the amount they study.
D. Walker’s Turf Quality Index representing how turf is better managed in proportion to the grade the Superintendent receives in Agry 365T.
_____5. The availability of Fe, Mn, Zn, and Cu increases as soil pH
A. increases
B. decreases
C. exceeds 8.3
_____ 6. Which nutrient has its availablitly influenced most by redox potential of the soil?
A. Boron B. Manganese C. Potassium D. Chlorine
Questions 7 and 8 - Answer these two questions based on the data given
Soil A Soil B
Soil-water pH 5.2 5.2
SMP Buffer pH 6.7 6.4
____ 7. Which of these Indiana soils requires more lime to raise soil pH to 6.5?
A. Soil A B. Soil B C. The same, (pH = 5.2)
____ 8. Which Indiana soil has the greater cation exchange capacity (C.E.C)?
A. Soil A B. Soil B C. CEC is the same
____ 9. High P applications may induce this micronutrient deficiency on turf if it is found in marginal quantities in the soil.
A. Mo
B. B
C. Cl
D. Fe
E. All of these
_____10. Manganese can cause problems on some soils by
A. inhibiting Al uptake.
B. reducing cation exchange.
C. being toxic at low pH, deficient at high pH.
D. being toxic at high pH, deficient at low pH.
_____11. The ratio for N:P2O5:K2O in turfgrass clippings is approximately:
A) 6:14 B) 4:1:3 C) 4:1:7 D) 8:1:3 E) 5:7:3
____ 12. Which of these nutrients might become chelated in an organic soil and become less available to
plants thus resulting in a deficiency?
A. Mo
B. B
C. Cu
D. Cl
E. All of these
_____ 13. Which of these nutrients commonly applied to turf is on the “target” list by some states for
removing it from fertilizers used on home lawns, if soil tests do not confirm a need for the
nutrient.
A. Nitrogen B. Phosphorus C. Potassium D. Iron E. Boron
_____ 14. Which fertilizer nutrient considers the CEC of the soil when determining the critical level in
the soil and in considering the optimum fertilizer to be applied?
A. Nitrogen B. Phosphorus C. Potassium D. Iron E. Boron
_____ 15. When is it most optimal to apply your highest percentage the annual amount of nitrogen
fertilizer that you apply to cool season turfgrasses in the Midwest?
A. Spring B. Summer C. Fall D. Mid-winter
Bonus: (2 points)
As a new assistant superintendent, what recommendation woud you make to your employer who has urged you to order Wally’s Special Micronutreient Blend for all your golf courses fairways and greens? Your budget is tight and he recommends you do this rather than hire extra labor for the up coming golf tournament.