An extensive non-LTE abundance analysis based on Na i 5890/5896 doublet lines was carried out for a large unbiased sample of \sim 120 A-type main-sequence stars ( including 23 Hyades stars ) covering a wide v _ { e } \sin i range of \sim 10–300 km s ^ { -1 } , with an aim to examine whether the Na abundances in such A dwarfs can be reliably established from these strong Na i D lines . The resulting abundances ( [ Na/H ] _ { 58 } ) , which were obtained by applying the T _ { eff } -dependent microturbulent velocities of \xi \sim 2–4 km s ^ { -1 } with a peak at T _ { eff } \sim 8000 K ( typical for A stars ) , turned out generally negative with a large diversity ( from \sim - 1 to \sim 0 ) , while showing a sign of v _ { e } \sin i -dependence ( decreasing toward higher rotation ) . However , the reality of this apparently subsolar trend is very questionable , since these [ Na/H ] _ { 58 } are systematically lower by \sim 0.3–0.6 dex than more reliable [ Na/H ] _ { 61 } ( derived from weak Na i 6154/6161 lines for sharp-line stars ) . Considering the large \xi -sensitivity of the abundances derived from these saturated Na i D lines , we regard that [ Na/H ] _ { 58 } must have been erroneously underestimated , suspecting that the conventional \xi values are improperly too large at least for such strong high-forming Na i 5890/5896 lines , presumably due to the depth-dependence of \xi decreasing with height . The nature of atmospheric turbulent velocity field in mid-to-late A stars would have to be more investigated before we can determine reliable sodium abundances from these strong resonance D lines .