EFFECT OFF APPLICATION TIMING OF NITROGEN AND SEEDING RATESON TOTAL RRY MATTER OF BREAD WHEAT

Abstract

A field trial was conducted at the Experiment Farm، College of Agriculture. Abu Ghraib ، Baghdad ،Iraq in two winter season 2000-2002 .  The objectives were to investigate the effect of application timing of nitrogen levels and seeding rates on some growth characters، dry weight yield at different stages. Seeding rates 80 ،120،160 kg/ha were assigned in the main plots ،nitrogen levels 200،300،400 kg /ha in the sub plots and application timing of nitrogen in sub – sub plots. Nitrogen timings included five combinations of growth stages ( ZGs00، ZGs21، ZGs32and ZGs(49  it was D 1: 1/2N at ZGs00  + 1/2N at ZGs21 ، D2 : 1/2N at ZGs00  +1/4N at ZGs21+1/4N at ZGs32 ، D3 : 1/2N at ZGs00  +1/4N at ZGs21+ 1/4N at ZGs49، D4: 1/2N at ZGs00  +1/4N at ZGs32+ 1/4N at ZGs49 ، D5 : 1/2N at ZGs00 +1/6N at ZGs21 +1/6N at ZGs32+ 1/6N at ZGs49. That higher mean of dry matter  weight in higher seed rate (160 kg / a ) in all growth stages and biological yield .Nitrogen level of 400 kg/ha gave higher means dry matter weight ) in all growth stages and biological yield  in both seasons . The application timing in (D5) produced  higher dry matter  weight in both seasons .