Name____________________

CSS 315 Quiz 2 May 5, 1999

Choose the one best answer (2 points each) and mark the appropriate letter.

1. Which combination of solid phases of phosphate compounds would be typically found in acid and alkaline soils?

a. Fe and Al phosphates in acid soil and tricalcium phosphate in alkaline soils

b. Fe and Al phosphates in alkaline soil and tricalcium phosphate in acid soils

c. H₂PO₄ in acid soils and PO₄^2- in alkaline soils.

d. H₂PO₄ in acid soils and monocalcium phosphate in alkaline soils.

2. Potassium as K⁺ held by cation exchange on surfaces in soils:

a. can not go into soil solution and be available to plants

b. is plant available

c. is held by electrostatic attraction

d. share electrons

d. a and c

e. b and c

f. none of the above

3. How can decomposition of organic matter cause soil acidity?

a. releases Al³⁺ from organic matter that splits water and releases H

b. has a liming effect that causes leaching of basic cations

c. produces strong bases during decomposition

d. releases CO₂ which forms H₂CO₃

4. Which of the following can be considered a neutral salt that has no effect on soil pH?

a. calcium chloride

b. calcium carbonate

c. ammonium nitrate

d. urea

5. A soil pH of 5.4:

a. should always be limed to at least pH 6.5 if it is economically feasible

b. is not necessarily of concern because there is no free Al³⁺ in soil solution

c. requires an SMP buffer test and should be limed according to the crops to be grown

d. requires an assessment of active pH and limed to a pH of 6.5 or greater.

6. Slowly available K:

a. can be released from between the partially opened lattices of partially weathered hydrous micas or illite clay minerals

b. is soluble K⁺ in soil solution

c. is K in primary minerals fixed in the lattice clay structure

d. is measured in a standard NH₄OAc solution in soil testing

7. Commercial phosphate fertilizer such as triple superphosphate:

a. is made by mining apatite which is reacted with acids to form phosphate fertilizer

b. can be made in unlimited amounts

c. is made by grinding apatite and using density separation techniques to obtain the P ferilizer

d. none of the above

e. b and c

8. An example of phosphate adsorption is:

a. soluble Al³⁺ reacting with phosphate to form a 3 dimensional precipitate of an Al phosphate compound

b. soluble Fe²⁺ reacting with phosphate to form a 3 dimensional precipitate of an Fe phosphate compound

c. ligand exchange of soluble phosphate anions with OH or OH₂ groups on a solid surface forming a monolayer of phosphate anions at the surface of the solid.

d. penetration of phosphate into a granule of CaCO₃

9. (8). You just bought a parcel of land that has a soil Jory which has a pH of 4.9 and low P soil test levels. What management steps would you take to increase P availability to grow small grains and clover seed crops.

9. (3) Explain how seasonal climate or factors that affect soil temperature and moisture can affect the uptake of K by plants.

(5) 11. Make up your own question and answer it on a topic not covered in the test but that has to do with the material covered since the last quiz (2 points for question and 3 for answer). The question and answer needs to be substantial and well thought out.