الفهرس 
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Abstract
Two field experiments were conducted at the Agricultural ’Reasearch and experimental center. Faculty of Agriculture at Moshtohor Kalubia, Egypt, during the two successive growing seasons of 1997 I 98 and 1988 I 99 to study the effect of four weed control treatments, (Grasp, Granstar, Granstar + Grasp and unweeded check) and the two wheat cultivars Le. Sakha 69 and sids 7 and four nitrogen levels on weed growth, wheat growth, yield and yield components of wheat. The . soil of the experiments was clay loam with PH value of 8, containing 2.3% ’. organic matter and 8-12 PPm available P. Each experiment included 32 treatments which were the combination of four nitrogen fertilization rates Le 60, 90, 120 and 150 kg N/fed, the two wheat cultivars and four weed control treatments. The chemical weed control treatments used in this investigation were:
1- Tralkoxydin which is known commercially as ”Grasp 10% Ec. ” it was applied at 3 -4 leaf stage of wheat plants (after 30 days from sowing) as post - emergence at the rate of 100 g. a. il fed (ILl fed) .
2- Express which is known commercially as Granstar 75%, it was applied after 15 days from sowing as postemergence at the rate 8 g. per I fed.
2- Granstar significantly increased number of stalks in the second season.
3- All weed control treatments had no significant spike length in both growing season as compared with un weeded treatment.
b- After 101 Days from Sowing:
1- Number of leaves/m2, plant height and spike length (em) were not significantly affected by weed control treatments in both growing season .
2- Granstar and mixture of Granstar and Grasp significantly increased number of stalks/m2 compared with Grasp and control treatments in both growing season.
3- The mixture and Granstar treatments significantly increased the number of spikes/m2 in the frist season as compared with Grasp and un weeded check but in the second season all weed control treatments significantly increased number of spikes / m2 as compared with un weeded check
C - After 121 Days from Sowing :
1- Number of leaves / m2 was increased by using Granstar and mixture of Granstar and Grasp only in the first season as compared with unweeded check, but not affected by all weed control treatments in the second season.
2- The greatest values of number of spikes / m2 were < recorded from mixture treatment and Granstar treatment. The?