Date of Award


Degree Type


Degree Name

Doctor of Philosophy




Dr. Don Hayden

Second Advisor

Dr. André Lachance

Third Advisor

Dr. Greg Thorn


Field and greenhouse soil studies were designed to test the effect of stabilized biosolids and coal fly ash as management on the plant-parasitic nematode Meloidogyne hapla. The trials were conducted in a Bryanston silt loam in Southwestern Ontario formed on a calcareous substrate. Fly ash was obtained from the Lambton Generating station in Sarnia, Ontario and stabilized biosolids from lagoons at Glencoe, Ontario. Field and greenhouse crops included carrot (Daucus carota L.) and tomato (Lycopersicon esculentum Mill), each grown from seeds. Amendment ratios of biosolids and fly ash and application rates were established based on international guidelines and previous studies for the use of biosolids and ash in soils. Field trials included amendments of 1.5%, 3%, 4.5%, 6%, and 7.5% (w/w) of each raw material. Greenhouse trials included additions of 2.5%, 5%, 7.5%, 10%, and 12.5% (w/w) of each raw material. Changes in parameters that might affect nematode viability were monitored including electrical conductivity, pH, biocontrol agents (bacterial and fungal colony forming units), selected heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn), and plant yield. Carrot yield was improved with increased amendments while infested carrots did not show visible nematode damage. Tomatoes grown with amendments showed improved yields relative to controls in the presence of nematode infection. None of the amendment application rates altered EC, pH, CFU, or metals enough to impact nematode populations. It can be concluded that the amendment application rates tested in this study for the raw materials used were below threshold levels that impact nematode populations. Future work should take into consideration the impact of the raw materials on parameters that control nematodes so that application rates include levels (upper and lower) that affect nematode variability.



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