Effect of integrated weed management practices on the growth, yield, quality and economic of onion (Allium cepa L.)

Abstract

A field study was conducted at research field of Spices Research Sub-Centre (SRSC), Faridpur, Bangladesh to find out the efficacy of weed management practices on the growth, yield, quality and economics of onion with the variety BARI Piaz-6. Thirteen treatments such as: T1-control as check (no weeding), T2-weed free, T3-one hand weeding (HW) at 45 days after transplanting (DAT), T4-two HW at 25 and 45 DAT, T5-three HW at 25, 45 and 65 DAT, T6-pre-emergence (PE) spray of pendimethalin 33 EC @ 330g a.i/litre + one HW at 45 DAT, T7- PE spray of pendimethalin 33 EC @ 330g a.i/litre + two HW at 45 and 65 DAT, T8- post emergence (POE) spray of pendimethalin 33 EC @ 330g a.i/litre at 25 DAT + one HW at 65 DAT, T9- PE spray of oxyfluorfen 23.5 EC @ 235g a.i./litre + one HW at 45 DAT, T10- PE spray of oxyfluorfen 23.5 EC @ 235g a.i./litre + two HW at 45 & 65 DAT, T11- POE spray of oxyfluorfen 23.5 EC @ 235g a.i./litre at 25 DAT + one HW at 65 DAT, T12- PE spray of pendimethalin 33 EC @ 330g a.i/litre + POE spray of oxyfluorfen 23.5 EC @ 235g a.i./litre at 45 DAT + one HW at 65 DAT and T13- PE spray of oxyfluorfen 23.5 EC @ 235g a.i./litre + POE spray of pendimethalin 33 EC @ 330g a.i/litre at 45 DAT + one HW at 65 DAT were compared by randomized complete block design with three replications. The study revealed that the weed management treatments under the study significantly influenced all parameters except total soluble solid content of onion bulb. Weed density had reverse effect on growth, development and yield of onion. Among the weed’s infestation, Cyperus rotundus (55-60%), Echinochloa crusgalli (10-15%) and Chenopodium album (8-10%) were predominant. The highest weed density (137.25 weeds/m2) were recorded from the T1. The lowest weed density (15.24 weeds/m2) were observed from T13. The T3 had the least weed control efficacy (23.56%). The maximum fresh yield (19.49 t/ha) of onion bulb were obtained from T2 followed by T13 (19.31 t/ha). The highest benefit-cost ratio (2.19) was calculated from the T13 closely followed by T12 (2.18). From this study it was concluded that Pre-emergence application (PE) application of oxyflourfen or pendimethalin + post-emergence (POE) application of oxyflourfen or pendimethalin at 45 DAT (days after transplanting) + once HW (hand weeding) at 65 DAT and also PE of oxyflourfen or pendimethalin + twice HW at 45 & 65 DAT exhibited good performance to control weeds in onion field.