Effect of fe and zn on growth and yield of sunflower in asaline soil in qom province

little information is available about the role of microelements on crop yield under saline condition. calcareous soils, low in organic matter, are highly prone to iron and zinc deficiency and thus lower productivity of several crop plants. study of iron and zinc effect on growth and yield of sunflower is necessary due to saline and calcareous condition in sunflowerand field in qom province, central iran. during 2001-2003, two field experiments were conducted in a systematic randomized complete blocks design, consisted of : 1- two soil application levels of fe (10 and 20) kg. ha-1 iron chelate and a spray treatment of feso4 ( 5 per 1000)2- four soil application levels of zn (10, 20, 30 and 60) kg. ha-1 and a spray treatment of znso4 ( 5 per 1000) and as well as a control (without fe and zn application) in three replicates. the biennial results showed using 20 kg. ha-1 iron chelate(soil application) and 20 kg. ha-1 zn (soil application) increased seed yield significantly, where as there was no significant defference between dry matter of treatments (soil application) in comparison with control(exept for 30 kg. ha-1 zn treatment). also fe spray treatment had no significant effect on seed yield and dry matter, however, zn spray treatment, decreased seed yield but had no effect on dry matter(p0.05). increasing fe application had no significant effect on oil seed content compared to control, where as application zn, up to 20 kg. ha-1 , increased oil content and applying more amounts, decreased it. in addition , spraying fe and zn, had no significant effect on oil seed content. application of fe, raised head diameter, 1000- seed weight and lowered plant height. the same was found in zn treatments ( exept for 60 kg. ha-1 treatment). totally, the result of this experiment showed, application of 20 kg. ha-1 iron chelate and/ or 30 kg. ha-1 zn, increased plant tolerance to salinity and increased head diameter , 1000-seed weight and as a result increased seed yield. in excess zn treatment (60 kg. ha-1), probebly, due to induced deficiency of iron , the yield decreased. key word: fe, zn, salinity, yield, oil content and sunflower