Midterm material clarifications

Hi Sandra, 

I had a few questions about the midterm material if you don't mind answering them, I would be very grateful.

1)Which soil definition would you like us to know for the midterm; Do we need to know both the soil scientists' and the engineers/horticulturists'?

2)Do we have to memorize the soil textural triangle?

3)Do we need to know how to draw montmorilonite and kaolinite phyllosilicates or any other chemical structure?

4)Do we need to memorize the names of secondary clay minerals and their characteristics aside from phyllosilicates?

Thank you!

1) Definition of a soil used by soil scientists - you do not need to memorize it, but know the key words e.g. natural, dynamic, medium for plant growth etc.

2) Textural triangle - no you do not need to memorize the triangle but you should know the difference between distinct soil textures e.g. clay versus loam versus sandy soil.

3) You do not need to draw the structures of phyllosilicate clay structures in BUT you should know the building blocks (Si-tetrahedron and Al-octahedraon) and 2:1 versus 1:1

4) Colloids - it would be helpful to understand that soil colloids include 2ndary phyllosilicates + one or two examples. Fe/Al oxides for example, form coatings and help stabilize aggregates (i.e. one of the cements).