Respiration parameters determined by the ISO-17155 method as potential indicators of copper pollution in vineyard soils after long-term fungicide treatment

Abstract

This study seeks to determine the impact of copper-based fungicides on the respiration of vineyard soils. The ISO-17155 is an international standard recommended for monitoring soil quality by the evaluation of the effects of pollutants on soil microbial activity. Respiration curves and derived parameters [i.e., basal respiration (RB), substrate-induced respiration (RS), lag time (tlag), growth rate (μ), time to the peak maximum (tpeakmax), respiratory-activation quotient (QR), and the cumulative O2 consumption (CR)] were determined from 95 vineyard soils that covered a wide range of Cu contents. Statistical analyses showed that most of the variance of the ISO-17155 parameters was due to soil pH and organic C content, but not to the Cu pollution. When the parameters were expressed as a function of soil organic C content, the effect of soil Cu content was found to be significant on RS and tpeakmax but not on RB and CR. The results indicated that threshold values of total (CuT) and exchangeable (CuEX) contents indicative of soil Cu pollution cannot be established. However, adequate management practices resulting in soil organic C contents>2% and pH>5.5 are recommended for preserving vineyard soil quality.