تأثير مواعيد رش الحديد و الزنك صفات النمو محصول الذرة البيضاء (Sorghum bicolor L)

A field has been carried out at the experimental station, college of Agriculture, in Abu-Ghralb, University of Baghdad, Iraq, during spring and autumn seasons 2014. The main objective is to find out the effects of iron concentration (0,60,90,120)mg.L-1, znic concentration (0,30,60,90) mg.L-1 and two stages of foliar application (flag leaf emergence and 50% flowering stage on some growth traits of Sorghum cv.Bohooth. 70.Layout of the experiment is R.C.B.D arranged in split-split plots designed with three replications, foliar application stages are assigned as main plots, iron as sub-plots, while zinc concentrations as a sub-sub plots. The results show, there is insignificant effects of foliar application stages on all growth traits. Also, the results show that the addition of iron at a con more than 60 mg.l-1 height, leaf area, percentage of chlorophyll in the leaf and percentage of iron and zinc in leaf. The Highest mean of plant height and leaf area 256 and 267cm is obtained when plants are sprayed with 90 and 120 mg.l-1 in spring and autumn seasons respectively. The Highest mean of 90 mg.l-1. leaf area(6709 and 6788)cm2is obtain when plants sprayed with 120mg.l-1. In addition the percentage of chlorophyll in the leaf and dry matter significantly influenced by iron con with 90mg.L-1 it is 40.6mmg.mg-1 chlorophyll in leaf and 14.465 t.ha-1 dry matter in spring season, while the percentage of chlorophyll and dry matter are 60.5 mmg.mg-1 and 14.429 t.L-1 dry matter in autumn season and are obtained by spraying plants with 120 mg.L-1 iron. Highest mean of iron in leaves in spring and autumn (75and 106) mg. kg leaf weight are obtained when plants sprayed with 120 mg.L-1 in spring and autumn seasons. Foliar application at time of flag leaf emergence give the highest plant height and leaf area, while foliar application at time of 50% flowering give the highest percentage of chlorophyll in leaf. There is no significant effect of time of foliar application on the percentage of chlorophyll, leaf area in autumn season, dry matter and percentage of iron and zinc in the leaf .Also, there is a significant effect of zinc concentration on plant height and leaf area,90 mg.L-1 Zn gives highest mean of high plant and leaf area (254 , 265 cm and 13.65, 13.662 t.h-1) in spring and autumn respectively. The result shows that zinc concentration 60 mg.L-1 give the highest mean of chlorophyll in the leaf in spring season, while 90 mg.L-1 of zinc give the highest mean of chlorophyl