Optimizing Row Spacing and Weed Management for Improved Yield and Essential Oil Production in Moldavian Balm (Dracocephalum moldavica )

Document Type : Original Article

Authors

1 University of Zanjan

2 university of zanajan

3 Islamic Azad University

10.22092/mpt.2026.373238.1226

Abstract

To evaluate the effects of weed competition on growth, seed yield, and essential oil content of Dracocephalum moldavica L., two factorial experiments were conducted in spring 2017 using a randomized complete block design with three replications at the Research Farm of the University of Zanjan. The first experiment assessed two row spacings (30 and 50 cm) and weed interference durations of 15, 30, 45, 60, and 75 days after emergence, plus a full season interference treatment. The second experiment used the same row spacings with weed free periods of 15, 30, 45, 60, and 75 days after emergence, along with a season long weed free control. Results indicated that full season weed interference produced the highest weed density and biomass. Under interference conditions, the maximum seed yield (140 g m⁻²) was obtained at 30 cm row spacing with 45 days of interference. Under weed free conditions, the highest seed yield (180 g m⁻²) was recorded at 50 cm spacing with season long weed control, whereas the lowest yield (48 g m⁻²) occurred at 30 cm spacing with weed control limited to the first 15 days after emergence. The highest essential oil content (0.41%) was achieved when weeds were allowed to interfere for only 15 days after emergence and were then removed, while the lowest content was observed under full season interference. Overall, a row spacing of 50 cm combined with weed control between 15 and 45 days after emergence is recommended to maximize both seed yield and essential oil production.

Keywords

Technology of Medicinal and Aromatic Plants of Iran
Volume 7, Issue 2 - Serial Number 13
January 2026
Pages 161-175

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