Residual zinc forms in weakly acidic and calcareous soil after and oilseed flax crop

Abstract

The different chemical forms of Zn found in soils exhibit different levels of reactivity, solubility and availability to plants. Sequential extraction procedures (SEP) are applied in soils to partition metal into operationally-defined geochemical fractions. The bioavailability of metals in soils is related to these chemical fractions and not to total metal content. Furthermore, single extraction methods, such as DTPA or Mehlich-3, are commonly used to predict Zn availability to plants. Other, more recently developed, method that try to simulate the conditions of the soil rhizosphere use a mixture of low-molecular-weight organic acids (LMWOAs) as extractants. According to various researchers, the BaCl2 reagent only extracts elements which are physically adsorbed on particles and it can be used to estimate the easily leachable Zn portion. Flax (Linum usitatisimum L.) is a major oilseed meadow crop grown throughout the world and is more sensitive to Zn deficiency than cereal crops such is wheat. The objectives of this study were to determine soil chemical Zn pools, potential Zn availability and easily leachable Zn in two residual soils after a flax harvest.