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

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 (R B ), substrate-induced respiration (R S ), lag time (t lag ), growth rate (μ), time to the peak maximum (t peakmax ), respiratory-activation quotient (Q R ), and the cumulative O 2 consumption (C R )] 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 R S and t peakmax but not on R B and C R. The results indicated that threshold values of total (Cu T ) and exchangeable (Cu EX ) 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.