In acid soils the principal chemical form of potassium available for plant uptake is ________.
A) H2KO2- B) K2O C) K+ D) P- E) HKO22-
Question 2Which of the following nutrient elements is usually present in the soil solution as an undissociated acid?
A) Fe B) Mo C) Cu D) B E) Zn
Question 3In acid soils the principal chemical form of phosphorus available for plant uptake is ________.
A) HPO42- B) P2O5 C) P3- D) H2PO4- E) P3+
Question 4In most soils, mineralization of soil organic matter is an important source of plant available ________.
A) phosphorus B) potassium C) both A and B D) none of the above
Question 5Other things being equal, a soil with 30 clay of the ________ type would be expected to have the greatest potassium-fixing capacity.
A) 1:1 B) 2:1
C) allophanic D) crystalline iron oxide
Question 6Mycorrhizae improve the nutrition of many plants by:
A) making the root cell membrane more permeable to phosphate ions.
B) masking P-fixation sites on the surface of certain soil minerals.
C) readily dissolving iron and aluminum phosphate compounds.
D) transporting phosphorus through the soil to the plant root.
E) fixing atmospheric phosphorus into forms readily used by plants.
Question 7If the CO2 content of soil air is 3.5, it is 100 times higher than that of the atmosphere.
Indicate whether the statement is true or false
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