Effect of Fulvic Acid on the Diffusion of Zinc to a Simulated Root System

To study the effect of a mobile chelating agent secreted by roots on the dissolution, chelation and back diffusion of zinc ions to plant roots in a simulated model, a chelating agent (fulvic acid from poultry manure) and distilled water (used as a reference) were passed through two sets each containing 0, 2.5, 5.0 and 7.5 ppm applied Zn. Fulvic acid enhanced the diffusion of zinc to the simulated root system and application of zinc further increased its cumulative diffusion. The kinetics of Zn diffusion to the root system conformed to a 1st order reaction. A constant flux of fulvic acid and water in the presence of applied zinc, significantly enhanced the dry matter production and uptake of zinc by corn (Zea mays L.).