Soil

Which soil textural class has the smallest average pore size but the greatest total volume of pore space?

• Clay

• Permeability

• Water Holding Capacity

• Loam

• Sand

What is in soil pore? Select all correct answers

• 50% filled with air (VOCs, oxygen, other gases)

• 50% filled with water (dissolved nutrients)

• Soil aggregates

• Soil peds

What are some basic units of clay or mineral in soils? Select all correct answers

• Kaolinite

• Silicon tetrahedron

• Smectite

• Vermiculite

• Alumina octahedron

Fill in the blank: Clay carries some _____   _____ charged and these charges do not change with pH changes

• isomorphous substitution

• permanently negative

• hydrated cation

• 2:1 mineral

Cation Exchange Capacity (CEC) refers to:

• A measure of soil ability to hold cations

• A measure of soil ability to hold anions

• The exchange of negative ions between soil and soil water

• The removal of positively charged ions from a soil

• The ability of a soil to attract, retain and release clay particles

Select all types of water in soil

• Capillary water

• Hygroscopic water

• Gravitational water

• Field capacity

• Wilting point

The upper unsaturated zone in the ground is termed the

• saturated zone

• phreatic zone

• supersaturated zone

• vadose zone

Water in vadose zone is essentially _______ due to the high water potential

• Mobile

• Immobile

• Saturated

• Unsaturated

• Percolating