Chapter 12 Flashcards
Agricultural operations can cause modifications to the C horizon.
False
Soils in wet tropical regions tend to have high organic matter and distinct profiles.
False
Weathered rock can be a source of essential minerals for plants.
True
Plants with low C:N ratios decay rapidly.
True
Sawdust added to soil can cause nitrogen deficiency.
True
Organic matter has a positive charge.
False
Higher earthworm populations are achieved in conventional tillage in comparison to no-till.
False
Plants infected with mycorrhizal fungi can absorb phosphorus better than noninfected plants.
True
Productive soils are densely packed.
False
A plant will extract water at field capacity until it reaches the permanent wilting point.
True
Sandy soils drain at a faster rate than clay soils.
True
Soils that are fertile and hold nutrients will have a low cation exchange capacity.
False
The pH of a soil is important because it influences the availability of plant nutrients.
True
Most crops grow well in soils with high salinity.
False
Crop yields will increase indefinitely in response to increasing fertilizer.
False
Synthetic fertilizers are used to provide organic matter to the soil.
False
Geologic erosion occurs at a faster rate than soil formation.
False
Erosion can leave behind less fertile subsoils.
True
How thick does the soil layer tend to be in agricultural regions? A. 3 to 4 inches B. 4 to 12 inches C. 3 to 4 feet D. 4 to 12 feet
C. 3 to 4 feet
A vertical section through the soil extending from the surface to the unweathered rock is best described as the: A. crust B. horizon C. profile D. core
C. profile
The topsoil is also known as the A. A horizon B. B horizon C. C horizon D. O horizon
A. A horizon
The subsoil is also known as the A. A horizon B. B horizon C. C horizon D. O horizon
B. B horizon
Which horizon has the highest amount of organic matter? A. A horizon B. B horizon C. C horizon D. O horizon
O horizon
Which of the following is one of the most important soils in agricultural production? A. aridisol B. mollisol C. gelisol D. spodosol
B. mollisol
Which is the predominant parent material for soils? A. igneous rock B. sedimentary rock C. metamorphic rock D. slate rock
B. sedimentary rock
The fineness or coarseness of a soil is called: A. soil field capacity B. soil structure C. soil aggregation D. soil texture
D. soil texture
Sand and silt are chemically composed mostly of: A. silica B. potassium C. soil aggregation D. soil texture
A. silica
Which soil particle contributes most to plant nutrition? A. sand B. silt C. clay D. silica
C. clay
The clustering of soil particles into various shapes is called: A. soil field capacity B. soil structure C. soil salinity D. soil texture
B. soil structure
The pH range that most field crops grow best at is: A. 4-5 B. 5-6 C. 6-7 D. 7-8
C. 6-7
Which of the following is an index that rates soils for intensive agricultural production on a 0 to 100-value scale? A. Crop Agricultural Index B. Crop Productivity Index C. Crop Parameter Index D. Crop Suitability Index
B. Crop Productivity Index
One distinction between organic and inorganic fertilizers is that organic fertilizers contain: A. carbon B. nitrogen C. potassium D. lime
A. carbon
Which of the following fertilizer nutrients is NOT obtained from mining? A. phosphorus B. nitrogen C. potassium D. calcium
B. nitrogen
Limestone is applied to soil to: A. increase organic matter B. add potassium C. add phosphorus D. increase soil pH
D. increase soil pH
