Zinc Adsorption and Relations with Soil Properties in Soils Forming on Calcareous Parent Material

The plant-available zinc (zn) in soil solution remains insufficient for optimal plant growth due to the strong adsorption of zinc by the soil components, the precipitation of zn as insoluble solid phases and the presence of inadequate chelating agents. however, each soil causes the zinc availability to be low in the soil solution by means of different mechanisms due to its own specific physicochemical characteristics. the aims of this study are: i) to determine the zinc adsorption characteristics of the experimental soils, ii) to determine the potential response of zn-deficient soils to zn fertilization and iii) to determine the mobility of zinc in the soils under extreme zn loading by langmuir and freundlich adsorption isotherms. zinc adsorption was determined by batch adsorption technique in 24 different zn-deficient soil samples from atabey plain, isparta, turkey. 25 ml of 0.01 m cacl_2 solution containing 0, 10, 25, 50, 100, 150, 200, and 300 mg zn l^-1 were equilibrated with 2 g of soils at a constant temperature of 20°c for 24 h. the appropriateness of the obtained adsorption data to the isotherm langmuir and freundlich models were tested by regression analysis. the relationships between the descriptive properties of the soils and the sorption parameters were revealed by pearson correlation analysis. it was determined that the langmuir adsorption maxima of the soils ranged between 1527-3448 mg kg^-1. correlation analyses revealed that the maximum adsorption of soils is associated with organic matter, lime, clay content, ph, and different geochemical fractions of oxide minerals. as a result, zn mobility, availability and solid-solution partition of added zn in the soil can be a result of the cooperative effects of soil properties.