Previous research suggests that calcium (Ca) can increase monovalent cation uptake and that Ca added to calcareous soils may improve plant growth irrespective of ammonia volatilization suppression. A greenhouse study was conducted to determine the influence of added Ca on growth and ammonium uptake by corn (Zea maysL.). Soils used were an acidic Bowie fine sandy loam (Fragic Paleudult) and a calcareous Weswood silt loam (Fluventic Ustochrept). Nitrogen (N) (0,56, 112 mg N/kg soil) and calcium (0, 42, 84 mg Ca/kg soil) were applied in factorial design, with the total amount applied split into 9 weekly applications. Corn was grown for 9 weeks following emergence. Growth parameters measured were plant height, leaf area, dry matter yields of roots and shoots, and shoot nitrogen and calcium concentrations. Total shoot content of these elements was computed by multiplying shoot concentration by shoot dry weight.