Study Set Content:
small swellings from the association of root bacteria and plants
Root nodules
Example of plants that have a root nodule
Legume Family(Fabaceae)- peas, beans, alfalfa, and few other plants such as alders
Dynamic, complex, constantly changing, part of the earth's crust that extends from a few centimeters deep in some places to hundreds of meters deep in others.
Soil
Factors affecting changes in soil
Climate, Parent material, Topography in the area, Vegetation, Living Organisms, Time
1 or 2 meters in an undisturbed area
Horizons
upper-layer usually extending down 10-20 cm
Topsoil
darker and upper portion
A horizon
0.3, 0.9 meter clay
B horizon or subsoil
10 centimeters; soil parent material and extends down to bedrock
C horizon
composed of many small particles bound together chemically or by a cementing matrix
Sands
individual clay particles
Micelles
particles so tiny that they cannot be seen through a powerful light microscope
Clay
consists of particles that are mostly too small to be seen without a lens or a microscope
Silt
Best agricultural soils
Loams
what is the mixture of loams
sand, clay and organic matter
Better loams composition
40% silt, 40% sand and 20% clay
High clay content
Heavy soil
High sand, low clay
Light soils
High water content and allow little water to pass through
Clay soil
Larger particles, porous, and don't retain much water
Coarse soils
