Effects of Coal Combustion By-Product–Encapsulated Ammonium Nitrate on Wheat Yield and Uptake of Nitrogen and Metals

Ammonium nitrate (AN) is an essential plant nutrient for plant growth. Ammonium nitrate is also an ingredient in explosives. Research is being conducted on reducing the explosiveness of AN by encapsulating it with the use of coal by-products. The objective of this greenhouse pot study was to determine the effects of class C and F fly ash and flue gas desulfurization-gypsum-encapsulated AN on biomass, grain, and straw yield and nitrogen and metals uptake by wheat. Encapsulated AN was mixed with a low-nitrogen soil at 56 and 112 kg N ha^-1^, as well as unencapsulated AN as a control, and planted with wheat (*Triticum aestivum* L.). The biomass yield was significantly higher than the other treatments for the high rate of class C fly ash-encapsulated AN treatment only. Grain yields were significantly higher for plants grown on the high rate of encapsulated AN treatments compared with treatments with low and high rates of unencapsulated AN. Coal by-product-encapsulated AN did not significantly affect nitrogen concentration in wheat biomass and grain compared with the unencapsulated AN treatments. In this pot study, encapsulated AN fertilizer was as effective as unencapsulated AN for wheat growth and grain yield, with no significant increase in tissue metal concentrations.