Campbell, Colin
- Department of Soil and Environment, Swedish University of Agricultural Sciences
- The James Hutton Institute
The Long-Term Sludge Experiment (LTSE) began in 1994 at nine UK field sites as part of continuing research into the effects of sludge-borne heavy metals on soil fertility. The long-term effects of Zn, Cu, and Cd on the most probable numbers of cells (MPN) of Rhizobium leguminosarum biovar trifolii were monitored for 8 yr in sludge-amended soils. To assess the statutory limits set by the UK Sludge (Use in Agriculture) Regulations, the experimental data were reviewed using statistical methods of meta-analysis. Previous LTSE studies have focused predominantly on statistical significance rather than effect size, whereas meta-analysis focuses on the magnitude and direction of an effect, i.e., the practical significance rather than its statistical significance. Results showed Zn to be the most toxic element causing an overall significant decrease in Rhizobium MPN of -26.6% during the LTSE. The effect of Cu showed no significant effect on Rhizobium MPN at concentrations below the UK limits, although a -5% decrease in Rhizobium MPN was observed in soils where total Cu ranged from 100 to
Journal of Environmental Quality
2016, volume: 45, number: 5, pages: 1572-1587
Publisher: AMER SOC AGRONOMY
Environmental Sciences
https://res.slu.se/id/publ/82903