Most books in the field of soil science are discipline oriented and deal in considerable detail with the particular field favoured by the author. This book departs from this practice and under the title of Soil ecology deals with the whole range of soil science. To some this may appear unnecessary, but when we consider the complexity of the soil matrix and the environment in which soil organisms and plant roots exist, there is a need to explain the chemical, physical and mineralogical properties of soils in which organisms occur. Without this firm foundation provided by an understanding of these non-biological factors in soil, it is impossible to understand how different components of soil biota operate and interact. Within the field of soil biology and soil ecology, the tradition has been to specialise in particular components of the topic, for example soil microbiology, soil biochemistry, soil zoology etc. In this book, Dr Killham has covered all these aspects of soil biology and adopted an integrated approach to the subject. It is this approach that will make this book so valuable to scientists and students working in the fields of soil and plant science and in environmental research.

Progress in science is made up of a series of steps, and often a step up from the previous level of knowledge depends on the development of new techniques. In soil microbiology, for example, the development of selective agars enabling the isolation and study of individual groups of bacteria and fungi improved our understanding of the ecology of these organisms against the background of the total populations. Later within this subject we see the development of studies on the organic compounds released from healthy plant roots. These studies greatly improved our understanding of the energy supplies for microorganisms in the rhizosphere and depended upon the development of paper chromatography for amino acid and sugar analyses and the development of 14C-labelling techniques developed in other areas of science. The application of electron microscopy to ultrathin sections of soil and rhizosphere was another technique which greatly advanced our understanding of the microecology of organisms in soil and their locations in relation to clay minerals, organic matter and particulate plant residues.