TABLE OF CONTENTS

Title Page    –         –         –         –         –         –         –         –         –         i

Certification –         –         –         –         –         –         –         –         –         ii

Dedication   –         –         –         –         –         –         –         –         –         iii

Acknowledgements         –         –         –         –         –         –         –         iv

Table of Contents  –         –         –         –         –         –         –         –         v-vi

CHAPTER ONE

I.0      Introduction –         –         –         –         –         –         –         –         1-3

CHAPTER TWO

2.0     Soil as a Habit for Micro-Organisms   –         –         –         –         4-5

2.1     Soil Microbiome Functions that Supports Plant Growth    –         6-9

2.2     Soil Microbiome Functions that Drive Nitrogen

Transformations   –         –         –         –         –         –         –         9-12

CHAPTER THREE

3.1     Beneficial Micro-Organism in the Soil          –         –         –         13

3.1.1  Azobacter    –         –         –         –         –         –         –         –         13-15

3.1.2  Azospirillum          –         –         –         –         –         –         –         15-18

3.1.3  Pseudomonas        –         –         –         –         –         –         –         18-20

3.2     Factors Affecting Nitrogen Fixation    –         –         –         –         20-21

3.2.1  Soil Water Content and Stress   –         –         –         –         –         21-22

3.2.2  Seasonality and Temperature Effects   –         –         –         –         22-24

3.2.3  Soil pH Stress        –         –         –         –         –         –         –         24-25

3.2.4  Soil Nutrients and Time Effects –         –         –         –         –         25-26

3.2.5  Microbial Association/Interaction        –         –         –         –         27

3.3     Soil Microbiota      –         –         –         –         –         –         –         27-28

3.3.1  Bacteria        –         –         –         –         –         –         –         –         28-29

3.4.2  Fungi –         –         –         –         –         –         –         –         –         29-32

3.4.3  Cyanobacteria and Algae –         –         –         –         –         –         32

3.4.4  Protozoa      –         –         –         –         –         –         –         –         32-33

CHAPTER FOUR

4.0 SUMMARY AND CONCLUSION

4.1     Summary     –         –         –         –         –         –         –         –         34-35

4.2     Conclusion  –         –         –         –         –         –         –         –         35

              References

CHAPTER ONE

1.0 INTRODUCTION

Soil consists of mineral particles, air water, soil organic matter, plant roots and living soil organisms. In terms of mass and volume, the living organisms constitute by far the smallest part of the soil. Typically 50% of the soil volume will be mineral particles, 25% air filled pores and 25% water filled pores, although this will vary. The soil organic matter constitutes 0.5-5% of the solid fraction by weight, except in peat soils where it is much higher (Mendes et al, 2013).

Soil organisms constitute 1-5% of the organic fraction, hence only 0.40% of the soil mass. However, soil cannot function naturally without the presence of life. Soil organisms are centrally involved in soil structure formation, litter turnover, nutrient availability and buffering and detoxifying properties soil physical properties such as water retention, water infiltration and aeration, are crucial in decomposition of organic matter and nutrient cycling and have potential for cleaning and detoxifying polluted soil or spills. In order to understand soil processes, it is therefore necessary to understand soil function of organisms living within it (Mendes et al, 2013).

The diversity of soil biota is greater in soil than in any other habitat on earth. Millions of species, most of which not yet described, habit the soil which has been referred to as the poor mans rainforest. Molecular techniques enable to investigate the species composition in the soil, but there is still a long way to go before the function and metabolism of most species are understood.

Micro-organisms are involved in biogeochemical cycling of nutrients, human synthesis and breakdown, soil aggregation, stabilization and mobilization and transfer of mineral nutrients from soil to plants. Nitrogen (N) Is a critical nutrients required for enhancing plant growth and ultimately crop production. Due to environmental pollution and plant toxicity caused by the heavy use of chemical fertilizers, the active approach is driven for development of biofertilizers by Nitrogen fixing microbes and phosphate solubilizing microbes too (Mazid et al, 2014). These microbial inoculants have become a hope for most countries, as far as economical and environmental view points are concerned. These beneficiary microorganisms are better alternatives for reclamation of wastelands when compared with chemical fertilizers. They can improve soil texture, structure and proliferate useful soil micro-organism. This seminar report will therefore review soil microorganisms and their activities.