Compost and biochar interactions with copper immobilisation in copper-enriched vineyard soils. (January 2018)

• Record Type: Journal Article
• Authors: Soja, Gerhard; Wimmer, Bernhard; Rosner, Franz; Faber, Florian; Dersch, Georg; von Chamier, Julia; Pardeller, Georg; Ameur, Dominik; Keiblinger, Katharina; Zehetner, Franz
• Is Part Of: Applied geochemistry. Volume 88:Part A(2018)
• Page Start: 40
• Page End: 48
• Publication Date: 2018-01
• Subjects: Trace element -- Stabilization -- Soil amendment -- Soil additive -- Vitis vinifera; Environmental geochemistry -- Periodicals; Water chemistry -- Periodicals; Geochemistry -- Social aspects -- Periodicals; Geochemistry -- Periodicals; 551.9
• DOI: 10.1016/j.apgeochem.2017.06.004
• Languages: English
• ISSNs: 0883-2927

Abstract

Abstract: Applications of Cu-based fungicides against downy mildew of grapevines have led to Cu accumulation in the topsoil of vineyards. In such soils, Cu may reach levels high enough to exert adverse effects on soil microorganisms, soil fauna and plant roots. This study aimed to test combinations of compost and biochar for their potential to decrease the bioavailability of Cu in Cu-enriched vineyard soils. Grapevine plants ( Vitis vinifera L. cv. Grüner Veltliner) were cultivated in soil columns equipped as microlysimeters during two vegetation periods under greenhouse conditions. The two experimental soils differed in pH (6.2 and 7.2, resp.), organic carbon (2.7 and 0.9%, resp.) and EDTA-Cu (97 and 198 mg kg −1, resp.). Treatments differed in the mixing ratio of compost and biochar, feedstock for biochar and post-pyrolysis modification of biochar. Standard addition rates amounted to 4 kg additive m −2 . Cu uptake into the grapevine shoots and leaves hardly responded to the different soil additive treatments. The roots buffered different Cu availability with increased Cu accumulation and largely prevented excessive translocation to aerial plant parts. The soil with lower pH and higher organic carbon content showed more vigorous shoot growth and higher leaf Cu concentrations than the soil of neutral pH in spite of lower EDTA-Cu concentrations of the soil. Soil analyses at the end of the experiment showed that the CaCl2 -extractable fraction of Cu was lower in the neutral soil (3% of EDTA-Cu) than in the more acidic soil richer in Corg (8%). The novelty of this study is the inclusion of Cu speciation for investigating the effects of the soil additives. Differences between treatments were more pronounced for Cu 2+ than for CaCl2 -extractable Cu. All tested additive treatments in the acidic soil showed clear reductions of Cu 2+ compared to the control without additives whereas this effect was less expressed but still recognizable in the neutral soil. In the soil pore water the Cu concentrations showed a Cu-mobilizing effect of the additives in the neutral soil, a mostly not significant effect in the acidic soil and a clear decrease of the Cu 2+ fraction that was more distinct in the acidic than in the neutral soil. Although the Cu 2+ fraction that was successfully reduced by the tested additives usually constitutes only <1% of total Cu in soil, this fraction is ecotoxicologically more relevant than the prevailing organically bound fraction. Highlights: Cu translocation from soils into plant tissues mainly depended on soil pH and DOC. Compost and biochar enhanced Cu mobilization in a neutral vineyard soil. The ecotoxicologically relevant Cu 2+ fraction was reduced by compost and biochar. Carboxylation of biochar did not further enhance Cu 2+ -immobilization.