Thisbook isabout ions, about variable-chargesurfacesand about models. Jti about ions because most of the substances in which soil scientists are interested occur in the soil solution as ions. This applies to both plant nutrients and pollutants. Thus the, reilction between soil and say phosphate does not involve a substance called "phosphate"; it involves phosphate ions. Ions are charged particles. When these charged particles react with charged surfaces, the outcome of the reaction is affected by both the charge on the particles and the charge on the surfaces. Hence we also need to understand...

Plant Nutrition - From Genetic Engineering to Field Practice, the 12th International Colloquium on Plant Nutrition, is the latest in a series which began in 1954. Early meetings were mainly concerned with the practical problems of soil fertility, with soil assessment, fertilizer requirements and methods of analysis. As the colloquia have progressed, the emphasis has slowly changed. The practical problems are still important, but there is increasing emphasis on plant physiology, plant biochemistry, membrane biochemistry, and even on the chemistry of genes which control the proteins...