The sites in certain clay minerals which fix potassium ions are also capable of fixing which other ion?
A) NO3- B) Ca2+ C) H2PO4- D) NH4+ E) H+
Question 2You would be most likely to find P deficient plants in which location?
A) a corn field in sub-Saharan Africa
B) a vegetable garden in India
C) a pasture in the Netherlands
D) an apple orchard in New York
E) a Douglas Fir forest in Oregon
Question 3If a manager can afford only a limited amount of soluble P fertilizer for a calcareous soil with low phosphorus availability, the best plant growth is likely to be obtained if the P fertilizer is applied ________.
A) well in advance of the plant's main period of nutrient uptake
B) evenly across the entire area to be fertilized and mixed thoroughly with the soil in the root zone
C) in narrow bands or localized concentrations
D) in combination with ground limestone
E) a combination of both B and D would be best
Question 4In most soils, mineralization of soil organic matter is an important source of plant available ________.
A) potassium B) phosphorus C) both A and B D) none of the above
Question 5Mycorrhizae improve the nutrition of many plants by ________.
A) masking P-fixation sites on the surface of certain soil minerals
B) making the root cell membrane more permeable to phosphate ions
C) transporting phosphorus through the soil to the plant root
D) fixing atmospheric phosphorus into forms readily used by plants
E) readily dissolving iron and aluminum phosphate compounds
Question 6In a soil at pH 5.0, most of the inorganic P is likely to be in the form of ________.
A) hydrous iron and aluminum phosphates
B) hydroxy apatites
C) tricalcium phosphates
D) phospholipids
E) monocalcium phosphates
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