The cation exchange capacities of alkaline soils are generally higher than those of acid soils (Vertisols excepted). Which of the following characteristics of alkaline soils most likely accounts for this high CEC?
A) high content of hydrous oxides of iron and aluminum
B) high content of 2:1 type clays
C) high exchangeable calcium
D) high exchangeable sodium content
E) high humus content
Question 2
Poor plant growth in a well-drained irrigated soil in an arid region (pH=8.0 ) is most likely due to ________.
A) phosphate toxicity
B) calcium toxicity
C) molybdenum deficiency
D) iron deficiency
E) manganese toxicity