Effect of Applied Iron on Desorption and Uptake of Iron by Wheat Plants

Abstract

Kinetic, fractionation and uptake studies was conducted in pot experiment to evaluate iron release and its bioavailability and uptake by wheat in calcareous soils. Iron applied in the form of Fe-EDDHA at rates of 0, 10, and 20 ppm Fe, in soils varying in contents of CaCO3 (2.13, 14.66 and 25.34 %) at 20, 40 and 80 days. Kinetic study was applied to understand the mechanism of Fe desorption and improving the effi ciency of Fe uptake by plants. Results proved that, the Elovich, power function, hyperbola and parabolic diffusion kinetic models gave high conformity to describe the desorption rate of iron (II) from the studied soils. However,
according to higher R2 and lower SE values, both the Elovich and hyperbola models were the most appropriate models as compared to other kinetic models tested. Fractionation study indicated that, a gradual increase in different iron fractions was observed due to Fe application up to 40 days of incubation period. The effect of varying levels of Fe-EDDHA was signifi cant; with respect to water soluble, exchangeable and Pb-displaceable iron content in soil. However, increasing CaCO3 content in soils signifi cantly decreased all iron fractions in the soils used. Pot experiment proved that, the effects of applied Fe resulted in signifi cant differences regarding dry weight, available Fe, FeII and Fe uptake by wheat plants. Application of 20 ppm Fe recorded the highest as compared to other treatments. Regression equation proved that, wheat dry weight is mostly affected by both DTPA-Fe, Fe uptake by plant; water soluble Fe and exchangeable Fe in soil.