Document Type : Research Paper
Authors
1 Department of Horticultural Science and Engineering, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
2 Assistant professor, Department of Horticultural science, College of Agriculture, University of Kurdistan, Sanandaj, Iran
3 Department of Plant Production and Genetic, Faculty of Agriculture, University of Kurdistan, Sanandaj, Iran
Abstract
Objective: The cultivation of fennel is expanding due to its favorable market demand and various applications in the food and pharmaceutical industries. Weeds are one of the most important factors causing damage in fennel fields. As a result, it is essential to identify the most effective method for weeds control in fennel cultivation.
Methods: In this research, the effects of 11 different weed control methods, including glyphosate, paraquat, afalon, diuron, vinegar, one-time cultivation, two-time cultivation, hand weeding, flame weeding, weed-infested, and weed-free conditions, on weeds growth, as well as the yield-attributed and phytochemical characteristics of fennel such as essential oil content and components, were studied. The experiment was carried out as a randomized complete block design in 2021 at the Faculty of Agriculture, University of Kurdistan.
Results: Herbicide treatment had a significant effect on the dry weight of aerial parts, thousand seed weight, fruit yield, essential oil content and yield of fennel, as well as the dry weight of weeds. However, the plant height and the number of umbels per plant of fennel were not significantly affected by the herbicide treatment. The highest fennel fruit yield (3.95 tons/ha) was obtained in the weed-free treatment, followed by hand weeding and diuron treatments, which produced 3.63 and 3.3 tons/ha, respectively. The lowest weed dry weight (3.54 g/m²) was recorded in the weed-free treatment, though it was not significantly different from the hand weeding and flame weeding treatments. The essential oil content of fennel fruits did not differ significantly among the treatments (except the weed-free treatment). The highest essential oil yield (133.3 L/ha) was obtained from the fruits of the hand weeding treatment, while the lowest yield (63.9 L/ha) was found in the fruits of the glyphosate treatment. The dominant compounds in the essential oil were similar in all treatments and were included anethole, fenchone, and d-limonene. The highest amount of anethole (73.53%), fenchone (12.21%), and d-limonene (11.56%) were observed in the glyphosate, weed-infested and vinegar treatments, respectively.
Conclusion: If the aim is proper weed control and achieving higher fruit and essential oil yield with minimal environmental damage, hand weeding was the best treatment after the weed-free condition. If, in addition to fennel yield, reducing weed control costs is also considered, the diuron was the best treatment. In terms of essential oil quality, characterized by high amounts of anethole and fenchone, and low level of estragole, the weed-infested treatment was the most favorable.
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