Document Type : Research Article
Authors
1
M.Sc Grauated in Drug Plants, Fasa Branch, Islamic Azad University, Fasa, Iran
2
Department of Agronomy, Fasa Branch, Islamic Azad University, Fasa, Iran
Abstract
Introduction
Environmental condition and appropriate planting date are the most important factors in producing optimal yield. Different planting dates lead to adaptation of plant vegetative growth period to different temperatures, daytime, and solar radiation. Therefore, it affects the development, production of biomass and ultimately plant yield. The effect of environmental factors on phenological stages of the plant makes the planting date differ from region to region and between genotypes in one region. Determining the optimal time for planting an herb is very important and it is a major factor to achieve potential yield. Furthermore, vermicompost plays an effective role by making available the necessary nutrients. Despite many studies on the positive effects of Vermicompost on the growth of different plants, few studies have investigated the use of vermicompost for Dracocephalum moldavica at different planting dates. Therefore, this experiment aimed to examine the effects of different amounts of vermicompost on the growth, yield, and essential oil of Dracocephalum moldavica at different planting dates.
Materials and Methods
This study was conducted byfactorial experiment based on completely randomized block design. The first factor included different planting dates at four levels (20 February, 5 March, 20 March, and 3 April) and the second factor included vermicompost at three levels (control and 5 and 10 t.ha-1 of vermicompost). Samples were taken from plants in the field at 50% flowering stage to measure the concentration of leaf elements and physiological traits. At the end of the growth period, were measured the height, the number of lateral branches, dry weights of aerial organs, and root dry weight. To measure the percentage of essential oil, were harvested aerial organs in different treatments at the flowering stage. Analysis of data variances was performed using SAS software version 9.1. Duncan’s Multiple Range test was used to a comparison between means at p ≤ 0.05. It should be noted that the results of mean comparison were only presented for the traits that the effect of experimental factors on them was statistically significant.
Results and Discussion
The results indicated that the highest nitrogen and phosphorus content of leaves and dry weight of Dracocephalum moldavica were obtained in a treatment of 10 t.ha-1 of vermicompost. The delayed planting changed physiological traits, including chlorophyll content and relative water content of leaves. Delayed planting due to the higher heat and drought stress decreased root growth and thus caused low water absorption from the soil. Therefore, the delay in planting reduced some growth indices of Dracocephalum moldavica Because of improved absorption of nutrients such as nitrogen, vermicompost resulted in further synthesis of the photosynthesis pigments. Regarding the results of this experiment, the greatest shoot dry weight, dry weight root and essence percentage were obtained by applying 10 t.ha-1 of vermicompost, while the lowest one was observed in control treatment without applying vermicompost fertilizer. There was an increase in essential oil percentage and yield by the use of 10 t.ha-1 of vermicompost. Furthermore, the planting date of 3 April reduced the yield of essential oil compared to the planting date of 20 March.
Conclusions
In general, the highest quantitative and qualitative yields of Dracocephalum moldavica were seen in the treatment of 10 t.ha-1 of vermicompost. We recommend the planting date of 20 February and 10 t.ha-1 of vermicompost for Dracocephalum moldavica planting. Providing a suitable growth medium, vermicompost increased the growth of Dracocephalum moldavica Therefore, organic fertilizers can be used to improve the quantitative and qualitative yield of herbs, and they are useful for medicinal applications in the perspective of this plant.
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