This book emphasize the interrelations among plants, animal, and microbes, by establishing the fundamental physical and chemicals properties of the soil habitat and then functionally characterising the major components of the soil biota and some of their most important interactions. The Fundamental principles underpinning soil ecology are established and this then enables and integrated approach to explore and understand the process of soil nutrient cycling and the ecology of extreme soil conditions such as soil water stress. This book is designed to meet the increasing challenges faced by today’s environmental scientists, ecologists, agriculturalist, an biotechnologists.