Teaching Organic Farming and Gardening

Soil Chemistry and Fertility

Unit 2.2 | 5
Instructor’s Lecture Outline

Lecture Outline: Soil Chemistry and Fertility

for the instructor

A. Pre-Assessment Questions

1. What are some of the essential plant nutrients?


2. How do plants obtain them from the soil?


3. What may happen if levels of one essential plant nutrient are very low or very high?


4. What is soil pH and why is it important to know the pH of your soil?


5. How does the organic matter content of the soil influence soil fertility?

B. Introduction to Basic Chemistry Concepts

1. Atoms and elements


2. Compounds, molecules, and atomic bonds


3. Ions


4. Elements needed by plants


5. Chemical reactions


6. Adsorption vs. absorption


7. Organic vs. organic

C. Soil Colloids

1. Definition


2. Importance

D. Soil Solution

1. Definition

E. Cation Exchange Capacity (CEC) and Base Saturation

1. CEC

a) Measurement (meq/100g soil or cmol/kg [new units, numbers are the same])

b) Factors influencing CEC

2. Base saturation

a) Definitions

b) Significance

F. Anion Exchange

1. Introduction


2. Definitions

G. pH

1. What is pH?


2. Effect of pH on nutrient availability and uptake

H. Acidity

1. Definitions


2. Distribution of acid soils