Name____________________

  CSS 315        Quiz 1        April 17, 1998

 

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

 

Match questions 1-5 with answers on right (answers on right can be used more than once).

 

__1.  An element that is beneficial but not essential for plant growth                 a. Fe

                                                                                                                                    b. N

c. Al

 __2.  An essential element that plants fix directly from atmosphere                                    d. Si

e. Pb

__3.   An essential micro nutrient                                                                                    f. C

g. K

__4.   A nutrient that is commonly deficient in soils for crop productions

 

__5.   A macro and essential nutrient that is largely found and released

from the mineral phase of soils.

 

 

6. Blue green algae and the Azola fern both derive benefits from each other in the following way:

 

a.  where the algae provides energy to the plant and fern fixes N2 which is a non-symbiotic relationship

b.  where the algae fixes N2 and is considered a free-living organism

c.  where the algae fixes N2 and the fern provides energy to the algae which is a symbiotic relationship

d.  where the algae provides energy to the plant and fern fixes N2 which is a symbiotic relationship

 

7.  The person who in the 19th century destroyed the humus theory (plants get C from soil) and established that H and O in plants comes from water.

a.         Justus von Liebig

b.         Jethro Tull

c.         J. R. Glauaber

d.         none of the above.

 

(8) 8. Describe the importance or how the C:N ratio of organic residues added to soils can be a factor in controlling net mineralization of N from the residue during decomposition.  What are the generalized C:N ratios that are threshold values for residues that control net N mineralization and net N immobilization.

 

 

 

 

 

 

 

 

 

 

(9) 9. Urea fertilizer is added to soil - describe all the major N pathways/transformations, forms, and pools where the N from the urea might end up by harvest time for a corn crop.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

(4 ) 10.  a. For the following nutrient pools indicate the type of term associated with release of a nutrient from the solid phase to soil solution - choose from weathering or mineralization.

 

Solid/mineral phase

 

Organic matter phase

 

b.  Differentiate weathering vs. mineralization