After drying to eliminate the water in plant litter, which two elements account for about 80 of the ...

After drying to eliminate the water in plant litter, which two elements account for about 80 of the dry weight?
 
  A) N and C B) Ca and C C) C and H D) N and S E) C and O

Question 2

Which of the following added to a soil would be likely to result in the greatest level of soil organic matter after several years of decomposition?
 
  A) the compost produced by composting 5 Mg of plant leaf material
  B) the manure produced by feeding cattle 5 Mg carbon in plant residues
  C) 5 Mg of carbon in plant roots
  D) 5 Mg of carbon in plant tops

Question 3

Which of the following pools contain the largest amount of the world's carbon?
 
  A) soil B) atmosphere C) animals D) vegetation

Question 4

Which of the following is a (are) major source(s) of the carbon dioxide now being added to the atmosphere in excess of the amount taken out by plants?
 
  A) destruction of natural forests
  B) loss of soil organic matter
  C) burning of fossil fuels
  D) all of the above
  E) none of the above

Question 5

Which of the following is a (are) greenhouse gas(es) contributed to the atmosphere by soils?
 
  A) carbon dioxide
  B) methane
  C) nitrous oxides
  D) all of the above
  E) none of the above

Question 6

Which of the following statements concerning applications or capabilities of soil moisture measuring devices is (are) true for the electrical resistance block?
 
  A) requires destructive sampling for each measurement
  B) good to turn on automatic irrigation at -50 kPa
  C) used to turn on irrigation when soil moisture potential reaches -200 kPa
  D) would give the same reading for both a loamy sand and a silt loam if both contained 15 moisture
  E) both A and D