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Two field experiments were conducted during successive summer seasons of 2007 and 2008 at Sakha Agricultural Research Station to investigate the efficacy of some weed control treatments i.e. butralin, Prometryne and fulazifop-p-butyle, whether alone or in combination, or plus one hand hoeing in addition to the hand hoeing twice for controlling annual weeds and their effects on some growth characters, seed yield and its components of sunflower. Results indicated that the herbicides, whether in combination, or plus one hand hoeing decreased dry weight of total weeds during the two seasons. The treatments ( butralin and prometryne) plus fluazifop-p-butyl reduced the dry weight of total weeds by 83.5 and 84.1 %, respectively in the first season and 86.2 and 88.7 %, respectively in the second season while, the herbicides plus one hand hoeing reduced the dry weight of total weeds 84.1, 87.7 and 85.5 %, respectively in the first season and, 93.3, 95.8 and 94.4 % respectively in the second season as compared to the control at 65 days from sowing. Hand hoeing twice was reduced total weeds only by 81.1 and 91.7 %. Therefore, it can be used herbicides, whether combined between in, or plus one hand hoeing for the control of most annual weeds. Results revealed that all studied herbicides plus one hand hoeing or in combination significantly increased growth characters of sunflower i.e. plant height, stem diameter and dry weight/plant during the growth stage and at harvest. (Butralin, prometryne and fluzazifop-p-butyle) plus one hand hoeing increased seed yield/fed by about 47.91, 48.62 and 44.84 % and, by about 45.45, 45.86 and 42.21%, during both growing seasons, respectively as compared to the control t. Data also cleared that all herbicide treatments slightly decreased chlorophyll a, b and total chlorophyll but did not adversely affect oil content of sunflower seeds. These results indicated that under heavy invested soil with annual weeds, it is possible to apply herbicides i.e. butralin at 2.5 l/fed, prometryne at 1.0 l/fed, and fluazifop-p-butyl at 1.0 l/fed followed by (one hand hoeing) after 30 days from sowing or combined between in). Also, the highest net return was obtained by herbicides plus one hand hoeing and hand hoeing twice. These practices gave the height reduction in annual weeds and increased sunflower yield and its components. Thus, these herbicidal treatments can replace hand hoeing for the control of annual weeds in sunflower crop. |
