Major Relationships between Iron and Soil Characteristics under Different Vegetation Cover in the South-East of Côte d'Ivoire

To identify the main soil properties influencing the dynamics of iron in the main agricultural land use activities in the south-east of Côte d'Ivoire, soil samples were taken from fields of rubber, rice and in natural forest, in the plots of block B29. The iron concentrations in the soils were determined by atomic emission spectroscopy with inductively coupled plasma, the physical and chemical characteristics of the soil (pH, organic carbon, total nitrogen, assimilable phosphorus, exchangeable cations, the capacity of exchange, sand, clay and silt) were analyzed according to the usual methods. The results show that free iron (Fed) is relatively more concentrated in the surface horizons, firstly under rice cultivation, then secondarily under rubber cultivation, compared to the soil under natural forest. The bioavailability of iron in the soil has highlighted a significant correlation between iron and three parameters, namely, clay and fine sand which reflect the fixing power of the soil, then the sum of exchangeable cations. By contributing to the iron storage potential in the soil, these parameters should not be underestimated, especially in cultivated soils. They should be seen as important components of ecological agriculture.