Inorganic soil components, sorption

McCall and Agin (1985) speculated that the rapid sorption-desorption of picloram on soils was associated with external sites of organic matter, whereas the slower kinetics could be ascribed to particle diffusion (PD) in organic or inorganic soil components. The amount of picloram associated with the external sites remained nearly constant with time, while that associated with internal sites increased greatly over time. 

The aim of this chapter is to provide the current state of knowledge on the factors that affect the mobility of trace elements in soil environments. Special attention is given to the influence of inorganic and organic ligands, including nutrients and root exudates, on the sorption—desorption processes of trace elements in cationic and anionic forms on/from soil components and soils. 

Sorption of trace elements onto soil components is greatly affected by pH, ionic factors, nature of the sorbents, redox reactions, and so on, but the sorption of elements in cationic form differs greatly from that of elements in anionic form. The presence of organic and inorganic ligands (including nutrients) in soil environments has a very important role in the sorption-desorption processes of trace elements. 

In contrast to sorption studies, relatively little information is available on the desorption of trace elements from soils or soil components as affected by organic and inorganic ligands. Desorption studies have showed biphasic reaction processes for sorption and desorption of trace elements (Sparks, 1990) a fast reaction followed by a slow reaction. 

Although triazines are dominantly sorbed by soil organic matter, the clay minerals also make a substantial contribution to triazine sorption by soils. For instance, the organic and inorganic components comprise 11% and 89%... 

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