Effects of leaching solution properties and volume on transport of metals and cations from a riviera fine sand

Abstract

A column leaching study was conducted using a Riviera fine sand (Loamy, siliceous, hyperthermic, Arenic Glossaqualf), sampled at 30 cm increments to 150 cm depth, from a commercial grapefruit grove to evaluate the effects of leaching solution properties on the leaching of Zn, Cu, Mn, Fe, Ca, and Mg in seven pore volumes of leachate. The concentration of Cu in the leachate was highest in the surface horizon (0–30 cm), indicating its limited transport down the soil profile. The concentration of Zn was significantly greater in the 30–60 cm depth sample than at the other depths. The peak concentrations of Fe and Mn were found in the 60–90 cm depth while those of Ca and Mg were in the 120–150 cm depth. The concentrations of the above metals and cations were significantly correlated with those of Mehlich 3 extractable elements in the soil. The addition of N, P, and K to the leaching solution increased the Zn, Mn, Ca, and Mg concentrations, but decreased Fe and Cu concentrations in the leachate. The concentrations of Ca, Mg, and Mn in the leachate were positively correlated, while those of Cu and Fe were negatively correlated with electrical conductivity of the leachate. The cumulative amounts of metals in the leachate increased with an increase in the pore volume of the leachate. The leaching solution pH was negatively correlated with concentrations of Zn, Mn, Fe, and positively correlated with concentration of Ca in the leachate.