Distribution and Amelioration of Manganese Toxic Soils

Abstract

To discuss the distribution and amelioration of Mn toxic soils requires their definition, something which is difficult since they neither lack vegetation nor carry a characteristic flora. In addition, they are not simply soils with high Mn reserves, because Mn availability depends on pH, Eh and on temperature and moisture (5, 50), and these factors may limit Mn supply in spite of the presence of large reserves of Mn oxides. These factors can of course also increase Mn supply to toxic concentrations, either because they are severe enough on their own, or because they interact with one another. Identifying the best treatment for a Mn toxic soil can therefore be difficult, and this task is made no easier by the fact that Eh and temperature effects can be short-lived and can disappear by the time Mn toxicity symptoms are visible.