Which of the following comparisons of the three different classes of salt-affected soils is correct?
A) Sodic soils are commonly formed by leaching saline-sodic soils.
B) Saline soils are generally higher in soluble salts than saline-sodic soils.
C) Sodic soils generally have the highest EC levels.
D) Sodic soils generally have the lowest pH.
E) The pH of saline soils is generally above 8.5.
Question 2Available phosphorus levels are constrained in alkaline and salt-affected soils because of ________.
A) high calcium and magnesium levels
B) high exchangeable sodium levels
C) high manganese levels
D) low hydrogen ion levels
E) high iron and aluminum levels
Question 3If you want to reclaim a saline soil, which of the following practices would you most likely use?
A) Leach the soil with water high in bicarbonates
B) Leach the soil with water high in Ca2+ and Mg2+.
C) Leach the soil with water having a high SAR ratio.
D) Add CaCO3 to reduce the exchangeable Na+ level.
E) Leach the soil with low salt containing water.
Question 4Sodic soils generally have a poor physical condition. To what is this most likely due?
A) low organic matter content
B) dispersal of the Na saturated soil colloids
C) impact of raindrops on the soil surface
D) high content of smectite in the soils
E) precipitation of the Ca2+ and Mg2+ ions as carbonates
Question 5You were advised to use elemental sulfur in the reclamation of a saline-sodic soil. Indicate how the sulfur helps bring about this reclamation.
A) Sulfur helps maintain high salt content while reducing exchangeable Na+ levels
B) Sulfur stimulates the formation of gypsum in the soil
C) Sulfur is oxidized to sulfates that will precipitate much of the exchangeable Na+
D) Sulfur leaches down into the soil and increases the soil pH
E) Sulfur is oxidized and forms sulfuric acid which, in turn, removes the exchangeable Na+
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