Objectives and Learning Outcomes

The aim of this course is to teach students regarding the concept of soil chemistry, soil composition and electrochemical potentials, colloidal chemistry of inorganic constitutes and impact of soil reactions on mineral nutrient availability. Students will be able to understand;

  1. Soil chemistry and soil formations.
  2. Need for acidic soil reactions; chemical characterization of saline and sodic soil.
  3. Nature of clay –organics complex and its impact on soil fertility.

After completion of this course, students will be able understand various chemical reactions occurring in the soil and impact of chemical properties of soil on plant growth along with management of plants according to the soil chemical nature.



  1. Introduction
  2. Silicate clay minerals: Structures and properties
  3. Allophanes and sesquioxides
  4. Soil colloids: Inorganic and organic 
  5. Charge characteristics of colloids: Sources and significance
  6. Cation exchange and its significance
  7. Zero point of charge
  8. DDL theory: Assumptions and properties
  9. Anion exchange and its significance
  10. Soil pH: Description and significance
  11. Basic cation saturation percentage: Description and significance; Buffering capacity of soils and significance
  12. Exchange equations: Limitations and assumptions
  13. Sorption in soil


  1. Determination of pH of different soil water ratios and saturated soil paste
  2. Determination of soluble and extractable cations in soil
  3. Determination of CEC
  4. Determination of basic cation saturation percentage
  5. Determination of lime contents in soil

Recommended Books

  1. Sparks, D.L. 1998. Soil Physical Chemistry. 2nd Ed. CRC Press, Boca Raton, FL, USA.
  2. Tan, K.H. 2011. 2001. Principles of Soil Chemistry. 4th Ed. CRC Press, Boca Raton, FL, USA.
  3. Essington, M.E. 2004. Soil and Water Chemistry: An Integrated Approach. CRC Press, Boca Raton, FL, USA.
  4. Tan, K.H. 2005. Soil Sampling, Preparation, and Analysis. 2nd Ed. CRC Press, Greensboro, GA, USA.

Assessment Criteria

Sessional: 08 (project, presentation, participation)

Project: 04

Presentation: 02

Participation: 02

Mid exam: 12

Final exam: 20

Practical exam: 20

Course Material