Loss of P to groundwater is likely to be most significant for which type of soil?
A) cultivated organic peat soils
B) sandy soils under pine forests (Spodosols)
C) calcareous soils
D) highly weathered tropical soils
E) silt loam soils formed in windblown loess
Question 2Compared to land that is not disturbed by tillage, conventionally plowed cropland usually loses much more ________.
A) dissolved P
B) particulate P
C) total P
D) both B and C are correct
E) none of the above is correct
Question 3The soils of the world contain more carbon than all the world's vegetation and the entire atmosphere, combined.
Indicate whether the statement is true or false
Question 4In various parts of the world, soil phosphorus is associated with which of the following environmental problems?
A) eutrophication of lakes because of a build-up of soil P in the watersheds
B) soil degradation because of depletion of soil phosphorus
C) toxic levels of phosphate in groundwater supplies
D) both A and B
E) all of the above
Question 5If you wanted to reduce the percentage sodium saturation from 30 to 5 in a sodic soil with a CEC of 20 cmolc/kg, how many cmolc's of CaSO4 would need to react with 1 kg of this soil?
A) 10 B) 30 C) 20 D) 5 E) 2
Question 6Compared to gypsum, elemental sulfur is sometimes considered a more desirable fertilizer material because ________
A) it is less dependent on warm, moist conditions for availability
B) it causes less soil acidity than gypsum
C) it contains more nutrient sulfur, kilogram for kilogram, than gypsum
D) plants respond to sulfur more rapidly
E) all of the above
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