Greenhouse and field experiments were conducted to determine the influence
of nitrogen (N) fertilization and DTPA-extractable soil zinc (Zn) on Zn con
centration in wheat (Triticum aestivum L., cv. Pioneer 2375) grain. Applica
tion of zinc sulfate (ZnSO4) in the range of 0 to 8 mg Zn kg(-1) increased
linearly DTPA-extractable Zn in an incubated calcareous soil from 0.3 to 5.
0 mg kg(-1). Application of these rates of ZnSO4 to the same soil under gre
enhouse conditions increased Zn concentration of wheat grain from 26 to 101
mg kg(-1). The influence of 134 kg urea-N ha(-1) on Zn concentration in wh
eat grain at eight field sites, with DTPA-extractable soil Zn levels rangin
g from 0.3 to 4.9 mg kg(-1), was studied. Nitrogen fertilizer increased whe
at-grain yields in four of the eight experiments but had little effect on g
rain-Zn concentration Grain-Zn concentration ranged from 31 to 45 mg kg(-1)
in N-fertilized plots at the various sites and was related (r=0.74*) to DT
PA-extractable soil Zn.