Selenium in onions grown in media amended with coal fly ashes collected with differing efficiencies

A study was conducted to learn if the extent of selenium uptake by onions grown on coal fly ash-amended growth media would be influenced by the particle size distribution of the fly ash. Two fly ashes having differing percentages of finely sized particles were used as plant growth amendments at percentages in the media to yield equal concentrations of selenium. Selenium concentrations in the harvested onion bulbs were found to be independent of fly ash particle size distribution.