Plant roots gain access to soil water primarily by the growth of the roots into moist soil. ...

Plant roots gain access to soil water primarily by the growth of the roots into moist soil.
 
  Indicate whether the statement is true or false

Question 2

The effect of soil organic matter on the amount of water available to plants is due to organic matter influence on total soil porosity as well as to the water-supplying power of the soil organic matter.
 
  Indicate whether the statement is true or false

Question 3

The priming effect refers to the excretion of growth promoting substance by certain bacteria during decomposition of fresh organic residues.
 
  Indicate whether the statement is true or false

Question 4

The most active decomposers of freshly added organic materials are able to sustain themselves by slowly attacking stable soil organic matter because of the head start they enjoy over other organisms, which were present only in inactive forms prior to the addition.
 
  Indicate whether the statement is true or false

Question 5

Given this table of plant residue analyses, choose the highest quality residue in terms of suitability to support an active community of soil organisms and rapid nutrient cycling.
 
  A B C D E
  C/N ratio 15 15 15 45 45
  Polyphenol content, 0.5 6.0 6.0 0.5 0.5
  Lignin content, 10 40 10 40 10
 
  A) residue A B) residue B C) residue C D) residue D E) residue E

Question 6

Under natural vegetation, about 60 to 90 of soil organic matter is in the ________ fraction.
 
  A) slow B) passive C) active

Question 7

The water potential at the leaf surfaces expressed in kPa is most likely to be ________.
 
  A) -33 B) -31,000 C) 33 D) -500 E) -10