This is a brief summary of a research project by Dr. Amy Turnbull, A&L Biologicals Agroecology Research Services Centre, London, Ontario. It looked at the impact of sulphur on tomato root disease and vine decline symptoms. Root and soil samples for the study were taken from processing tomato fields in Essex and Chatham-Kent.
Six tomato fields were visited in 2011. Healthy and diseased plants were pulled from three fields, while only healthy plants were taken from two fields and only diseased plants from one field. The soil surrounding the roots was analysed for nutrients. A higher concentration of sulphur was observed in healthy soil compared to diseased soil when comparing between plants pulled from the same field.
Sulfate was then tested in growth room studies. Sulfate sources were magnesium sulphate, ammonium sulphate and ferrous sulphate. Controls were magnesium chloride, ammonium chloride, and ferric chloride. Chemicals were added to 50 ppm and 500 ppm to naturally infested soil collected from a field with tomato vine decline symptoms. No difference in disease severity was noted in sulphate-treated plants using the amount of lesions on the roots or shoot biomass as indicators of disease. These trials were repeated twice with five plants per treatment.
Report from Dr. Amy Turnbull, A & L Biologicals Agroecology Research Services Centre, London, ON.