How many major textural classes of soil are there?
10
4
13
6
Which of these soil types is (typically) best for growing crops?
Silty
Loamy
Sandy
Clayey
True or False: There are more organisms in one teaspoon of soil than people on Earth.
True
False
How long can it take to develop 1 cm of topsoil?
1,000 Years
100 Years
50 Years
5 Years
How many tons of dry soil pass through an acre of earthworms in a year?
5
1
15
