GROWTH, YIELD AND YIELD COMPONENTS OF MAIZE (Zea mays L.) AS INFLUNCED BY NITROGEN FERTILIZATION LEVELS AND MECHANICAL WEED CONTROL TREATMENTS.

Two field experiments were conducted at Shandaweel Research Station farm




at Sohage during 2004 and 2005 seasons. This work aimed to find out the effect of




nitrogen fertilizer levels (90, 120 and 150 kg/fed.) and some mechanical weed




control treatments (hand hoeing at 15 and 30 DAS, hand hoeing ai 15 and 45 DAS1




hand hoeing at 30 and 45 DAS, hand hoeing at 15,30 and 45 DAS and unweeded)




on growth, yield and yield components of maize (single cross 10).Split-plot design ¡n




four replications was used in this study. The main plots were assigned to three




nitrogen fertilizer levels, while the five weed control treatments were assigned in




sub- plots.




Decreasing nitrogen rates reduced significantly dry weights of grassy weeds,




dry weight of broad leaved weeds and dry weight of total weeds. lncreaing nitrogen




levels from 90 to 150 kg/fed. increased signilnicantly all growth characters,




yield components and grain yield of maize.




All mechanical weed control treatments reduced the dry weights of grassy and




broad leaved weeds and total weeds compared with un-weeded. The most effective




weed control treatment against maize weeds were hand hoeing thrice at 15.30 and 45




DAS which controlled 88.1% of total weeds. Also, all weed treatmentš surpassed the




un-weeded in the all estimated maize characters, Hand hoeing thrice at 15,30 and 45




DAS was the superior treatment than other ones in growth characters, yield




components and grain yield of maize.




Maize plants treated with hand hoeing thrice at 15,30 and 45 DAS and fertilized




with 150 kg N/fed. gave the highest grain yield and yield components.