Adsorption properties of subtropical and tropical variable charge soils : implications from climate change and biochar amendment

This review paper attempts to summarize the progress made in research efforts conducted over the past years to study the surface chemical properties of the tropical and subtropical soils, usually called variable charge soils, and the way they response to different management. The paper is composed of an introductory section that provides a brief discussion on the surface chemical properties of these soils, and five other review sections. The focus of the following sections is on the evolution of surface chemical properties during the development of the variable charge properties (second section), interactions between oppositely charged particles and the resulting effects on the soil properties and especially on soil acidity (third section), the surface effects of low molecular weight organic acids sorbed to mineral surfaces and the chemical behavior of aluminum (fourth section), and the crop straw-derived biochar-induced changes of the surface chemical properties of these soils (fifth section). A discussion on the effect of climate change variables on the properties of the variable charge soils is included at the end of this review paper (sixth section)