استجابة اللوبياء لطرائق إضافة و تراكيز الكوبلت

الملخص EN

An experiment was carried out at the vegetable fields of Hort.

Dept., College of Agriculture , University of Baghdad to test two methods of cobalt application at five concentrations [0 (control) , 1 (Co1) , 2 (Co2) , 3 (Co3) and 4 (Co4 )mgCo.l-1) on growth and yield of cowpea Vigna unguculata L.

All treatments were implemented twice (30 and 44 days after sowing) during the season.

In addition recommended chemical fertilizer (60 kg urea.

and 260 kg.

triple superphosphate ha-1 was applied to all treatments at sowing , and 72 kg.

urea ha-1 was applied one month after germination.

A randomized complete block design was adopted with three replications .

Foliar spray increased significantly the number and weight of the root nodules , improved vegetative growth traits, and increased yield .In addition,and regardless the method of Co application , Co3 treatments dominated in all tested characteristics.

Except in the first season where Co4 was not significantly differed compared to Co3 in the number and fresh weight of root nodules .

Spraying cobalt at 3 mg.l-1 dominated in number of root nodules (113.6 and 68.3 nodule plant-1), nodule fresh weight (1.27 and 0.64 g), plant length (125.7 and 96.3 cm) , number of leaves (80.4 and 72.6 leaf.

Plant-1) , vegetative part dry weight (91.8 and 76.5 g.

Plant-1) , number of pods (32.7 and 30.5 pod.

Plant-1), average pod fresh weight (6.8 and 6.7) and highest pod yield (11.8 and 10.8 ton.

ha-1) for the two seasons respectively .

Accordingly spraying of cowpea plants with cobalt at 3 mg.l-1 twice during the season (30 and 44 days after sowing) was recommended.