Flashcards in Class Notes Deck (17)
What had a higher CEC between tetrahedra and octahedra?
What dictates the strength of molecules attraction to eachother?
Size of the valence shell
What is a factor in isomorphic sub?
Atomic radius. Number of subatomic particles in element determine size.
What is the anion exchange capacity?
Area surrounding cation exchange sites where anions are attracted to adsorbed hydrogen and cations.
What is the diffused layer?
The layer of cations that surround clays, attached to the CEC
What is the second diffused layer
Anions that surround the diffused layer due to their attraction to the cations in the diffused layer.
What determines a soils CEC
Relative proportion of humus to Clay
What kind of Clay is bentonite?
A smectite, therefor expansive Clay
How much surface area in 1 g Clay
10m2 to 800m2
What is cation exchange capacity?
Measure of a soils capacity to carry H+ in adsorption layer
Measured in mg H in 100 g soil
How can lime help improve soils?
Lime displaces additional acidifying elements on CEC to make room for nutrients like NPK
What are bases when referring to CEC
All cations other than H Fe and Al
How does al+++ get into Si tetrahedrons?
Similar in size to silica but has a higher valence.
Does isomorphic replacement happen In octahedrons?
Yes, aluminum can be replaced by Mg or Fe
What is the origin of smectites?
What soil order results from high smectite content
Vertisols - due to vertical fracturing allowing OM to penetrate soil profile