Contents: Section 1 INTRODUCTION 1. Agricultural microbiology and scope 2. History of microbiology Section 2 BASICS OF MICROBIOLOGY 3. Microbial cell: Constituents and composition 4. Prokaryotic cell metabolism 5. Nutrition, growth and culturing of microorganisms 6. Genetics of prokaryotes 7. Bacteriophages Section 3 SOIL BIOTA AND THEIR ECOLOGY 8. Soil: A habitat of microorganisms 9. Soil bacteria 10. Soil fungi 11. Soil green algae 12. Soil animals 13. Rhizosphere 14. Phyllosphere 15. Methods for studying soil microorganisms Section 4 BIOGEOCHEMICAL CYCLES OF PLANT NUTRIENTS 16. Carbon cycle 17. Organic matter decomposition and nutrient recycling 18. Nitrogen cycle and transformation 19. Nitrification and denitrification 20. Basics of biological nitrogen fixation 21. Non-symbiotic and associative nitrogen fixation 22. Legume-rhizobia symbiosis 23. Actinorhizal symbiosis (Actinorhiza) 24. Azolla- Anabaena symbiosis 25. Microbial transformation of soil phosphorus 26. Mycorrhizae 27. Microbial transformation sulfur in soil Section 5 EXPLOITATION OF MICROORGANISMS IN AGRICULTURE 28. Biofertilizers 29. Microbial insecticides and herbicides 30. Composting 31. Microbial interactions and biocontrol soil borne plant diseases 32. Biogas production 33. Microbiology of water 34. Wastewaters 35. Food microbiology This text book is written keeping in mind the contents of the syllabus of the course ‘Agricultural Microbiology’ taught in BSc.(Ag) degree program all over the country as the syllabus is approved in Deans’ committee at ICAR level. The book will be useful for students and the teachers teaching the course. The book has five sections namely basics of microbiology which deals with fundamental principles of general microbiology. Section two covers ecology of soil biota and organisms in soil liter interfaces. Third section is biogeochemical cycles of plant nutrients discussing microbiological transformation of important plant nutrients and their movement in the soil constituents. Fourth section relates with applied aspect of agriculturally useful microorganisms dealing with biofertilizers and biocontrol agents. Fifth section discusses qualities of drinkable water and food and water borne diseases directly concerned with human hygiene. A chapter on traditional and molecular techniques to study soil microorganisms and their activities in situ and laboratory is also incorporated. The language of the book is simple and subject matter is discussed with help of illustration such as graphs, charts, tables and pictures, keeping readers in mind. In the end of each chapter exercise in the form of questions has been incorporated to help the student to recapitulate the contents of the chapter.