Asian Journal of Plant and Soil Sciences

In order to evaluate the behavior of magnesium in three different agricultural soils within Nineveh Governorate, northern Iraq, some thermodynamic functions of the capacity and intensity relationships Q/I of magnesium were studied, the study was conducted on three sites with different types of vegetation cover, and each site was divided into two depths (surface, subsurface), thermodynamic functions were studied at three temperatures (278̊, 298̊, 318̊ Kelvin), the results obtained indicate that the average distribution coefficient (K_d) reached (16.45) L Kg^-1 when incubated at a temperature of 278̊ Kelvin, and when the samples were incubated at a temperature of 298̊ Kelvin, the average values increased, reaching (22.36) L Kg^-1, while when incubated at a temperature of 318̊ Kelvin, we find that there is an increase in the values in general, as the average reached (24.70) L Kg^-1, Regarding the relative ionic activity of magnesium AR_Mg, its value was (-0.728×10^-3) mole L^-1/2 at a temperature of 278̊ K, and when the equilibrium temperature was increased to 298̊ K, it led to an increase in the ionic activity values in the negative direction, as it reached (-0.970×10^-3) mole L^-1/2 as an average, while at a temperature of 318̊ K the rate was (-1.103×10^-3) mole L^-1/2, as for the values of mobile magnesium, the average reached (-28.28) Cmole Kg^-1 at a temperature of 278̊ Kelvin, and when the temperature increased to 298̊ Kelvin, the average was (-54.03) Cmole Kg^-1, and when the temperature increased to 318̊ K, the average reached (-67.74) Cmole Kg^-1. As for the potassium buffering capacity PBC_Mg, the lowest rate was recorded at a temperature of 278̊ K (36.65) Cmole Kg^-1, and the values gradually increased when the temperature increased to 298̊ K, the values were recorded as an average of (55.49) Cmole Kg^-1, and the highest values were reached when the incubation temperature increased to 318̊ K, as the general average of the values was (61.48) Cmole Kg^-1.