Effects of Coal Combustion Byproduct Encapsulated Ammonium Nitrate on Corn (Zea maize) Yield and Uptake of Nitrogen and Metals.

ABSTRACT

Ammonium nitrate (AN) is an essential plant nutrient for plant growth.  Ammonium nitrate is also an ingredient in explosives.  Research has shown that encapsulation of AN with coal byproducts reduced the explosiveness of AN.  The objective of this field study was to determine the effects of class C fly ash (FAC) and flue gas desulfurization-gypsum (FGDG) encapsulated ammonium nitrate on corn (Zea maize) grain and stover yield, nitrogen and metals uptake.  The study was conducted in 2011 and 2012 on a low nitrogen soil (Codorus silt loam) at the Beltsville Agricultural Research Center in Beltsville, Maryland. Plots were laid out as randomized complete block with four replications.  Corn (Variety-TA65713-VP) was planted on a 30 inch rows along with 112 kg ha^-1 phosphorus and potassium fertilizer as (0-45-50).  After germination encapsulated AN was applied at 56 and 112 kg N ha^-1 as well as non-encapsulated ammonium nitrate as a control.  Only the 2012 data will be presented. There was no significant difference in corn grain and stover yield between the non-encapsulated and capsulated ammonia nitrate fertilizer treatments.  Grain yield increased 14, 4.7 and 19.6 percent control, FAC and FGDG respectively when N rate increased from 56 to 112 kg N ha^-1. Stover yield also increased 20, 6.9 and 24 percent for control, FAC and FGDG respectively. However, only for the FGDG treatment was the difference significant.  Cadmium, lead and arsenic concentrations were below the instrument detection limits.  Coal byproduct encapsulated AN did not significantly affect nitrogen copper, manganese and zinc concentrations in corn grain and stover compared to the non-encapsulated ammonium nitrate treatments.  In this field study, encapsulated ammonium nitrate fertilizer was as effective as the non-encapsulated ammonium nitrate without significant increase in tissue metal concentrations.