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Definition
Organic and inorganic matter with very small particle size and a corresponingly large surface area per unity of mass. They are referred to as the active fraction becuase soil colloids hold nutrients, water, and other substnaces. |
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Term
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Definition
| 4 sided, Si (pole), can substitute AI for SI |
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Term
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Definition
| 8 sided structure, 6 ions ( oxygen except on edges), AI for the pole |
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Term
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Definition
if the 6 oxygen/ hydroxlysis are corrdinated with two AI atoms
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Term
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Definition
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Term
| List the major differences between the 5 sillicte clays |
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Definition
Kaolinite: Only 1:1 structure
Montmorillionite: High CEC, high shrink- swell, not pH dependent.
Illite: high potassium, no shrink- swell, moderate CEC
Vermiculite: Some expansion, high Mg, High CEC
Chlorite: 2:2 , high Mg, Moderately to low CEC, no shrink swell |
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Term
| What two processes are involved in clay formation? |
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Definition
1. Slight physical and chemical alteration of certian primary minerals.
2. Decompostion of primary minerals with the subsequent recrystalization of certian of their products into the sillicate clays. |
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Term
| Compare Fe and AI- oxide/ hydroxide clays to the silicate clays |
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Definition
| Oxide clays are highly weathered clays, non expanding clays, good building materials |
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Term
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Definition
Complex and rather resistant material modified from plant and animal residues or synthesized by soil organisms. ( biochemical reactions)
- Non-crystalline
- pH dependent sites
- large number of negative sites
- large surface area
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Term
| What is % base saturation? |
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Definition
| Proportion of CEC occupied by forming cations |
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Term
| Relationship between % base and pH of a given soil |
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Definition
| THe more basic the soil then the soil will be able to hold more nutrients. There will be more negative sites avaliable. |
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Term
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Definition
| Exchange of anions in the soil solution for anions adsorbed on the surface of clay and humus particles. |
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Term
| Which soil collids are usually associated with anion exchange property |
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Definition
| Anion exchange is very important in making anions available for plant growth, while at the same time retarding the leaching of anions from the soil. |
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Term
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Definition
| Replacement of one atom by another of similar sixe in a crystal lattice without disrupting or changing the crystal structure of the mineral |
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Term
| pH dependent negative sites |
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Definition
| Portion of the total charge of the soil particles that is affected by, and varies with, changes in pH |
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Term
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Definition
| charges not dependent upon pH |
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Term
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Definition
| To aggregate of clump together individual, tiny soil particles, especially fine clay, into clumpsor floccules |
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Term
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Definition
| To break up compound particles such as aggregates, into individula component particles |
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Term
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Definition
| Water content corresponding to an arbitrary limit between liquid and plastics states of consistency |
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