The influence of moisture on the residual effects of natural zinc chelates applied to two different soils

Abstract

The aim of this study was to compare the behavior of residual Zn from three natural chelates (Zn-aminolignosulfonate (Zn-AML),Zn-polyhydroxyphenylcarboxylate (Zn-PHP) and Zn-ethylenediamine disuccinate (Zn-EDDS)) applied at different rates (0, 5 and 10 mg Zn/kg soil) to a flax crop grown during the previous year. This incubation experiment was carried out over 75 days under two different moisture conditions (60% field capacity and waterlogged) in two different soils (acidic (Soil acid )and calcareous (Soil calc )). The potential available Zn concentration and short- term available Zn were estimated under both moisture conditions using the diethylenetriaminepentaacetic acid - triethanolamine (DTPA-TEA) and low-molecular-weight organic acids (LMWOAs) methods, respectively. Water- soluble Zn was estimated in both soils under 60% field capacity conditions. Immediately available Zn (the Zn concentration in the soil solution) was estimated under waterlogged conditions. The pH and Eh were also determined in both soils. Incubation of both soils under both moisture conditions led to decreases in the potential available Zn and short-term available Zn concentrations. Water-soluble Zn concentrations in soils under 60% field conditions, immediately available Zn in soils and the Eh parameter under waterlogged conditions also decreased with time. The residual effect of Zn-AML applied at a rate of 10 mg Zn/kg in Soil acid produced the highest available and short-term Zn concentrations, and the residual effect of Zn-EDDS produced the highest short-term Zn concentration in Soil calc .