| environ. | soil acidification A naturally occurring process in humid climates that has long been the subject of research, whose findings suggest acid precipitation effects. The generally accepted impact of soil acidification on the productivity of terrestrial plants is summarised as follows: as soil becomes more acidic the basic cations (Ca, Mg) on the soil exchange are replaced by hydrogen ions or solubilized metals. The basic cation, now in solution, can be leached through the soil. As time progresses the soil becomes less fertile and more acidic. Resultant decreases in soil pH cause reduced, less-active population of soil microorganisms, which in turn slow decomposition of plant residues and cycling of essential plant nutrients | acidificación de suelo |