Title: Sequential extraction of Cu and Zn from soil amended with bio-compost for 12 years: risk of leaching

Authors: Husam Al-Najar; David Dohle; Hannes Kurz; Jörn Breuer; Torsten Müller; Rudolf Schulz

Addresses: Environmental Engineering Department, IU Gaza, P.O. Box 108, Gaza Strip, Palestine ' Fertilisation and Soil Matter Dynamics, Institute of Crop Science, University of Hohenheim, 340i, D-70593 Stuttgart, Germany ' Institutes for Agricultural Chemistry, University of Hohenheim, D-70593 Stuttgart, Germany ' Agricultural Technology Center Augustenberg Neßlerstr, 25, 76227 Karlsruhe, Germany ' Fertilisation and Soil Matter Dynamics, Institute of Crop Science, University of Hohenheim, 340i, D-70593 Stuttgart, Germany ' Fertilisation and Soil Matter Dynamics, Institute of Crop Science, University of Hohenheim, 340i, D-70593 Stuttgart, Germany

Abstract: A long-term field experiment was set up on a Luvisol with various fertiliser treatments including bio-compost. The effect of compost application on total (aqua regia extractable) Cu and Zn contents in soil layers were investigated. After 12 years compost application, organic fractions considered as bioavailable and less accessible inorganic Cu and Zn fractions had altered compared to the treatments without compost application. In comparison to the topsoil, the subsoil aqua regia extractable Cu and Zn were higher in the mineral fertilisation treatment (topsoil: 18.46 mg Cu kg⁻¹, 62.89 mg Zn kg⁻¹; sub-soil: 19.89 mg Cu kg⁻¹, 66.88 mg Zn kg⁻¹), but lower in the compost treatment (topsoil: 22.58 mg Cu kg⁻¹, 70.80 mg Zn kg⁻¹; subsoil: 21.03 mg Cu kg⁻¹, 68.68 mg Zn kg⁻¹). In compost, Cu was mainly found in less accessible inorganic fractions and a smaller proportion in the organic fraction. In contrast, the organic fraction was most dominant for Zn followed by the less accessible inorganic fractions. Only a non-drastic accumulation of Cu and Zn in soil was detected. Cu and Zn fractionations in composts had the same trend of the corresponding fractions in the soil.

Keywords: biocompost; composting; copper; field experiment; luvisol; zinc; sequential extraction; leaching risks; fertiliser treatments; mineral fertilisation; compost treatment.

DOI: 10.1504/IJEWM.2016.081834

International Journal of Environment and Waste Management, 2016 Vol.18 No.4, pp.317 - 334

Received: 14 Feb 2016
Accepted: 18 Aug 2016
Published online: 27 Jan 2017 *

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