Answer to Question 1
Answer: Field capacity is the maximum amount of water that can be retained in the soil after gravitational water has drained away.
Answer to Question 2
Answer: Cations are positively charged ions of the soil. They act as nutrients in the soil. The ability of the colloids in the soil to attach to these cations for subsequent use for plants is highly variable by soil type and its measurement is a way to numerically define soil fertility.
