soils lab

•  These are the most chemically reactive component of the soil that are usually consisting of the humus and clay.

  Soil Colloids
• Soil colloids have tremendous surface area and have both positive and negative charges.


  True
• This is a 2:1 non-expanding type of clay


  Illite
• This is an expanding type of clay

  Montmorillonite
•  What method is used to prove the presence of charges on soil colloids?

  dye
•  Gentian violet is positively charged.


  True
•  Eosin red is positively charged


  false
• The method used to observe the swelling of colloidal clay.

  ring
• Dispersion of soil colloids is caused by this solution.

  NaOH
•  Flocculation of soil colloids is caused by this solution

  Ca (OH)2
• what is soil colloids
• . The process by which the ions adsorbed on the surface of colloids are exchanged for ions in soil solution.

  Ion exchange
• These ions are adsorbed on negatively charged surfaces.

  cation
•  These ions are adsorbed on positively charged surfaces

  Anion
•  Which clay colloids have the highest cation exchange capacity?

  Organic colloids
• .Which clay colloid has the least cation exchange capacity?

  Hydrous Oxide
•  Refers to the percentage of total cation exchange capacity occupied by exchangeable bases

  Base Saturation
• What are the exchangeable bases?

  Ca, Mg, K and Na
• What is ion exchange