The use of a physical field model to study the effects of remedially treated timber on the growth of perennial ryegrass (Lolium perenne) and rye (Secale cereale), and the accumulation of toxic preservative constituents in Lolium perenne
D C R Sinclair, G M Smith, A Bruce, H J Staines
Low cost laboratory model systems can be used to give relatively rapid indications of the environmental effects of preservative treated timber in soil contact. This paper details the effects of remedially treated timber on the growth of crops of Lolium perenne and Secale cereale seeded on soilbeds of different texture in close proximity to remedially treated creosoted pole sections. Lolium perenne sward samples were subjected to chemical analysis for fluoride and chromium content to identify bio-accumulation of these toxic preservative components. Significant but variable reductions in the dry weight yields of Lolium perenne samples were found in conjunction with increased fluoride and chromium contents, together with significant reductions in the density of Lolium perenne swards. The difference in soil texture however was found to be a more significant influence on the growth of Secale cereale than the presence of treated timber. Secale cereale plants within a crop canopy established on the lighter textured soil were characteristically larger and more numerous than plants from canopies on heavier soils. Results are discussed as part of an overall environmental assessment of the remedial treatment and in terms of the suitability of the physical field model as a testbed for such plant studies.