Soil Chemistry [antikvár]

1. INTRODUCTION 1.1. THE SUBJECT OF SOIL CHEMISTRY Soil chemistry deals with the investigation of the chemical composition of soils, the study of chemical changes and with the description of the laws that control the characteristic processes. A knowledge of soil chemistry is essential - for the interpretation of soil formation and development, - for the exact description of alkalinization and acidification, - for the prediction of the effect of amelioration, irrigation and drainage, - for the quantitative analysis of the interaction between the soil and nutritive elements, - for modelling of mass transport processes The prerequisite for establishing general laws is, however, the determination of the direction, extent and mechanism of - dissolution and precipitation, - oxidation and reduction, - adsorption and desorption, - mass transport (diffusion, leaching, convection, accumulation), and a detailed elucidation of the factors influencing the prevalence and interaction of these processes. It is only after the determination of these factors that one can approach theoretically the composition or changes in the composition of a system, or make attempts to model the state of equilibria and the movement of solutes (by using the static and dynamic models). It is quite obvious that the above problems can only be solved by the employment of the methods and law of related fields of sciences (chemistry, physics, mathematics) to soils, and by the application of results obtained in the other areas of soil science (soil physics, soil mineralogy, soil biology and soil genetics). The subject of soil chemistry can be divided into three major topics, namely: - investigation of the chemical composition of the soil components, - study of the chemical processes occurring in the soil, and the - development and application of appropriate methods for chemical analysis (Table LI). However, the exact definition of these areas is difficult and always arbitrary, to some extent, due to the wide overlapping of the different branches of soil science. During the compilation of this book, which deals with soil chemistry, our main intention was to give a survey of the chemical processes and principal interactions. (A short description of the soil components is included because of their essential effect on the equilibrium processes).