Exam 14: Soil Phosphorus and Potassium

Mycorrhizae improve the nutrition of many plants by ______.

The fixation of large amounts of potassium from applied fertilizer would reduce the cation exchange capacity of a soil.

In a soil at pH 5.0, most of the inorganic P is likely to be in the form of _______.

The nutrient most often limiting the growth of aquatic plants and algae in unpolluted fresh water lakes is ______.

Although only about 2 to 5 percent of the total P in most surface soils is in organic form, this form supplies nearly all the P taken up by plants.

In what range of soil pH is phosphorus generally most available to plants?

A soil with a very low equilibrium phosphorus concentration (EPC) is likely to be characterized by a very low potential buffering capacity (PBC).

The amount of both P and K fertilizer applied to US farmland has increased dramatically since 1980 as American farmers attempt to maximize profits and meet record demands for food.

In acid soils the principal chemical form of potassium available for plant uptake is ____.

The amount of P lost from agricultural soils by the process(s) of _____ is generally considerably greater than the corresponding losses of potassium.

Most soils with a high phosphorus fixing capacity are inherently fertile.

Eroded sediment usually contains about half as much P per kg as does the soil remaining on the eroded site.

The sites in certain clay minerals which fix potassium ions are also capable of fixing which other ion?

Luxury consumption of potassium most often occurs in coniferous forests growing on low potassium soils where the ecosystem can least afford it.

Unlike the use of nitrogen fertilizer on forests, the use of potassium fertilizer can be expected to increase the trees' resistance to diseases and/or pests.

Non-point source losses of which element are considered to be a serious water pollution problem because the resulting high concentration of the element in stream water is toxic to most fish.

Because of the complimentary ion effect, potassium is more readily leached from an acid soil than from a neutral soil.

In various parts of the world, soil phosphorus is associated with which of the following environmental problems?

The amount of K lost in subsurface drainage waters from humid region forested watersheds is generally far greater than the amount of P lost in this manner.