تأثير مبيدات الأدغال الكيماوية المضافة على الأجزاء الخضرية في مكافحة الأدغال و بعض الصفات الحقلية لمحصول قصب السكر Saccharum officinarum L. الراتون الأول

Abstract EN

Two experiments were conducted on sugarcane – Ratoon 1 in fields of the general sugarcane company in Missan governorate during April and July 2001 , to investigate the response of sugarcane yield , qualitiative characters and companion weeds to the foliage applied herbicides .

Randomized Completely Block Design with three replications were used in both experiments , and mean of treatments were compared according to least significance Difference ( L.

S.

D ) under 5% level .

The results obtained were as the following : 1.

Application of 1.92 kg a.i/ ha bentazon and 3.84 kg a.i/ ha glyphosate in April caused highest weed control percentage ( 80.5 % and 74.3% respectiviely ) .

Although , weed control percentage 90 days after application was reduced but the effect of these two treatments were continues and recorded the highest weed control percentage as compared to other treatments.

Application of herbicides in July , the treatment with 3.84 kg a.i/ha bentazon showed the highest weed control percentage ( 71.5% ) , and did not differ significantly with same herbicide used at rate 1.92 kg / a.i / gave 65.06 weed control .

2.

The effect of different herbicies on weed dry weight showed that the treatment with 1.92 a.i/ha bentazon in April and July gave lower dry weight 258.0 and 38.3 g/m2 , respectively , and this treatment didn’t differ significantly in reduction weeds dry weight with other glyphosate and bentazon treatments at higher rates .

3.

In general , application of glyphosate or bentazon carfentrazon + 2,4-D in April or July improved vegetative characters at harvest .

Sugarcane height and tillers number were increased as compared with untreated control and this was reflected on cane yield .

Application of bentazon at 0.96 kg a.i/ha or glyphosate at 3.8 kg a.i/ha in April gave highest cane yield 38.66 and 34.666 ton / ha respectively as compared with untreated control which gave 29.333 ton / ha .

Application of carfentrazon + 2,4-D at ( 0.03 + 0.32 ) kg a.i / ha in July recorded the highest cane yield 49.777 ton / ha followed by 44.889 ton / ha with each bentazon at 3.84 and 1.92 kg a.i/ha as compared with the untreated control which gave 38.222 ton / ha .