Soil Physical Chemistry is a comprehensive textbook that presents the fundamental principles and advanced concepts governing the chemical and electrochemical behaviour of soils. The book is designed to help students, researchers, teachers, and soil science professionals understand the interactions among soil minerals, clay particles, soil solution, nutrients, and organic matter.

The book begins with the basic chemical principles applied to soil physical chemistry and proceeds to explain the chemical composition of soil, silicate and nonsilicate clay minerals, and the relative stability of soil minerals. It provides a detailed discussion of the origin of charges in soils and the structure and properties of the diffuse double layer surrounding clay particles—key concepts for understanding soil colloidal behaviour and ion exchange processes.

Subsequent chapters examine cation exchange equilibria, anion adsorption, molecular adsorption, and phosphate fixation in soil. Special attention is given to the behaviour and availability of potassium, soil reaction, and the formation and management-related characteristics of saline, saline-alkali, and alkali soils.

The book also explores the electrochemical properties of clays, mineral stability equilibria, and the kinetics of nutrient adsorption and desorption. These topics are essential for understanding nutrient retention, release, mobility, and availability in different soil environments. The chemistry of waterlogged soils and the chemistry of soil organic matter are discussed in detail to provide a broader understanding of soil chemical transformations under varying environmental conditions.

With its systematic organization and emphasis on fundamental mechanisms, this book serves as a valuable reference for postgraduate students of Soil Science and Agricultural Chemistry, agricultural and environmental researchers, university teachers, and professionals involved in soil fertility, nutrient management, soil classification, and sustainable soil management.

Dr. Prasanna Kumar Das served as a Professor in the Department of Soil Science and Agricultural Chemistry at Odisha University of Agriculture and Technology (OUAT), Bhubaneswar. Following his retirement, he joined Siksha ‘O’ Anusandhan Deemed to be University, Bhubaneswar, as a Professor in the Department of Soil Science and Agricultural Chemistry, Faculty of Agricultural Sciences.

Dr. Das obtained his postgraduate and Ph.D. degrees in Soil Science and Agricultural Chemistry from OUAT. He began his academic career in 1987 as an Assistant Professor in the Department of Soil Science and Agricultural Chemistry, College of Agriculture, OUAT. His area of specialization is Soil Physical Chemistry.

With 32 years of teaching experience at the postgraduate and doctoral levels, Dr. Das taught subjects including Basic Chemistry, Soil Physical Chemistry, and Soil Mineralogy. He was widely appreciated for his ability to explain complex topics in a systematic and simplified manner.

Dr. Das has authored 31 research publications, primarily in the field of Soil Physical Chemistry. In addition to his teaching and research activities, he was actively involved in research projects related to the management of acid soils in Odisha. In recognition of his academic and professional contributions, he was admitted as a Fellow of the Hind Agri-Horticultural Society of India in 2009.

Chapter 1. Basic Chemical Principles Applied in Soil Physical Chemistry

Chapter 2. Chemical Composition of Soil

Chapter 3. Silicate and Nonsilicate Clay Minerals in Soil

Chapter 4. Relative Stability of the Minerals

Chapter 5. Charge Origin in Soil

Chapter 6. Structure and Properties of Diffuse Double Layer around the Clay Particles

Chapter 7. Cation Exchange Equilibria in Soil

Chapter 8. Anion Adsorption by Soil

Chapter 9. Molecular Adsorption in Soil

Chapter 10. Phosphate Fixation in Soil

Chapter 11. Potassium in Soil

Chapter 12. Soil Reaction

Chapter 13. Saline, Saline-Alkali and Alkali Soils

Chapter 14. Electrochemical Properties of Clays

Chapter 15. Mineral Stability Equilibria in Soil

Chapter 16. Kinetics of Nutrient Adsorption and Desorption in Soil

Chapter 17. Chemistry of Waterlogged Soils

Chapter 18. Chemistry of Soil Organic Matter