Evaluation of weed management practices on performance of onion (Allium cepa L.) bulb crop under different fertilizer levels.

摘要

In the alluvial soil of Navsari (Gujarat), a field experiment was conducted in rabi season to study the yield, quality and post-harvest life of onion (Allium cepa L.) cv. Gujata onion white-1 as affected by weed management and fertilizer levels during two consecutive years of 2008-09 and 2009-10. Weed population was decreased significantly with application of pendimethalin 1 kg/ha or oxyfluorfen 0.24 kg/ha supplement with one hand weeding at 40 DAT (W₅ or W₆) during both the seasons of investigation. Echinochloa spp., Trianthema portulacastrum L., Digera arvensis Forsk., Physalis minima L. and Cynodon dactylon (L.) Pers. were found as major weeds in experimentation. Further, pendimethalin @ 1.0 kg/ha followed by one hand weeding (W₅) produced higher onion bulb yield of 39.3, 36.6 and 38.0 t/ha during both years as well as in pooled, respectively, which was statistically on par with that obtained from treatments oxyflourfen 0.24 kg/ha+one hand weeding at 40 DAT (W₆) and weed free (W₉) treatments. Crop fertilized with higher levels of 125% RDF produced significantly the highest bulb yield of 37.5, 34.2 and 35.7 t/ha, respectively, which was 10.52 and 19.43% more than of the F₂ (100% RDF; 100:50:50, N:P₂O₅:K₂O kg/ha) and F₁ (75% RDF; 75:37.50:37.50, N:P₂O₅:K₂O kg/ha) levels, respectively, on the pooled basis. Regarding post-harvest life of bulbs, weight losses (%), black mould development (%) and sprouting (%) remained unaffected by weed management and fertilizer levels except significantly higher weight losses (%) were observed under W₅ (Pendimethalin 1 kg/ha pre-emergence+One hand weeding at 40 DAT) weed management treatment. On the basis of interaction, treatment combination of W₅F₂ (Pendimethalin 1 kg/ha coupled with one hand weeding at 40 DAT supplement with 100% RDF) was found most appropriate (39.9 t/ha) and profitable not only to secure the net return of Rs. 2,69,422/ha with 7.85 BCR per unit cost of onion production but also saved 25% of fertilizer. However, manual weeding may not be feasible and economical in the large onion cultivations.