Effects of ZnSO4 and Zn-EDTA broadcast or banded to soil on Zn bioavailability in wheat (Triticum aestivum L.) and Zn fractions in soil. (August 2018) - Zhao, Aiqing
Abstract: Human Zn deficiency is prevalent in developing countries, and staple grains are commonly bio-fortified to increase their Zn contents. We measured Zn content, distribution, and bioavailability in calcareous soil and in wheat plants ( Triticum aestivum L.) in Shaanxi Province, China, when either an organic Zn-ethylenediaminetetraacetate (Zn-EDTA) or an inorganic zinc sulfate heptahydrate (ZnSO4 ·7H2 O) Zn source was banded below the seedbed or broadcasted into soil. Compared with ZnSO4 ·7H2 O, Zn-EDTA fertilization produced higher Zn concentration and uptake in wheat plants. However, Zn bioavailability in grain remained low, with [phytate]/[Zn] ratio >15 and the resulting estimated dietary total absorbed zinc (TAZ) < 3 mg Zn/d. ZnSO4 banded into soil had little short-term effect on grain Zn concentration but had a high residual effect and promoted the maintenance of a high concentration of the Zn fraction bound to loose organic matter (LOM-Zn) in rhizosphere soil. Both ZnSO4 and Zn-EDTA were more efficient if uniformly mixed through the soil than if banded to soil. Both ZnSO4 and Zn-EDTA had limited effects on Zn bioavailability in wheat plants due to the high rate of Zn fixation in this calcareous soil. Highlights: Zn banded into soil had an unsatisfactory short-term effect on wheat Zn levels. Zn banded into soil produced high LOM-Zn levels. Zn banded into soil had a beneficial long-term effect on subsequent crops. Both Zn-EDTA and ZnSO4 were fixed at a high rate in this calcareous soil.