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 .