Section 1
Ammonium fixation would be expected to be greatest in soils containing a lot of______.
Vermiculite
Because of _______, soils developed in marine marshes can become extremely acid if drained for agriculture or used as topsoil.
Oxidation of Sulfides
In various parts of the world, soil phosphorus is associated with which of the following environmental problems?
Soil degradation because of depletion of soil phosphorus and eutrophication of lakes because of a build-up of soil P in the watershed
Ammonia losses are likely to be greatest if a nitrogen source is placed about 10 cm deep in ____
A calcareous sandy loam soil
If 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 _____.
In narrow bands or localized concentrations
Methemoglobinemia is principally a potential threat to _____.
Babies drinking water in high nitrate
Approximately what percentage of the P in surface soils is typically found in organic forms?
25-75%
Loss of P to groundwater is likely to be most significant for which type of soil?
Cultivated organic peat soils
Mycorrhizae improve the nutrition of many plants by ______.
Transporting phosphorus through the soil to the plant root
You would be most likely to find P deficient plants in which location?
A corn field in sub-Saharan Africa
Wetlands and forests growing along the banks of rivers remove much nitrogen from groundwater by the process of _________.
Denitrification
In order for nitrate to form from soil organic matter, _____ must be present in the soil.
Both A and B
The principal form of sulfur taken up by plants is ____.
Sulfate
To be practical, a nitrification inhibitor should kill or inhibit _____.
Nitrosomonas
The sulfur dioxide in the atmosphere ______.
Compared to the same soil used for cropland, a forested soil would be expected to lose _____ total P to streams draining the watershed.
Less
The amount of P lost from agricultural soils by the process(s) of _____ is generally considerably greater than the corresponding losses of potassium.
A. leaching
B. harvest removal
C. gaseous evolution
D. both b and c are correct
*E. none of the above are correct
None of the Above
In most soils, mineralization of soil organic matter is an important source of plant available ____.
Phosphorus
Compared to gypsum, elemental sulfur is sometimes considered a more desirable fertilizer material because _____
It contains more nutrient sulfur, kilogram for kilogram, than gypsum
Compared to land that is not disturbed by tillage, conventionally plowed cropland usually loses much more ______.
Particulate P and Total P
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.
*Potassium
*Phosphorus
Neither potassium nor phosphorus
Other things being equal, a soil with 30% clay of the ____ type would be expected to have the greatest phosphorus -fixing capacity.
Allophanic