The Effects of Planting Date and application Manure, Chemical Fertilizer on Some Morpho-physiological Characteristics and Essential Oil of Moldavian Balm (Dracocephalum moldavica L.)

Optimum planting date is very important and it is one of the important factors for maximizing yield production. Although, chemical fertilizers provide plant nutrients faster and more effective, but in order to increase the quality of products, especially the medicinal and aromatic plants, the use of organic fertilizers is better than chemical fertilizers. Organic fertilizers cause decreasing in bulk density and increasing water retention in the soil. Manure is one of the organic fertilizer sources which its application is conventional in sustainable management system of the soil. So, the present study was carried out in order to investigate effects of planting date and application of manure, chemical fertilizer on some morpho-physiological characteristics and essential oil of Moldavian Balm.

A split plot experiment was conducted in a randomized complete block design with three replications at the research farm of Shahrekord University in 2018. In this experiment, the main factor was 3 levels of planting dates: 20 April, 12 May and 3 June, while 6 levels of manure application: 1) no amended fertilizer 2) 25% urea + 75% manure 3) 50% urea + 50% manure 4) 75% urea + 25% manure 5) 100% urea and 6) 100% manure, were used as subplot factors.

The results showed that planting date and fertilizer had a significant effect on all the characteristics measured at this experiment. The interaction of planting date and different fertilizer treatments on all the measured traits except the stem diameter, length of main inflorescence and chlorophyll a was significant. The maximum stem diameter was related to 12 May while the maximum length of main inflorescence and chlorophyll a was belonged to the planting date of 3 June. The maximum amount of leaf dry weight was derived from 12 May + 100% manure, the maximum biological yield was obtained from 3 June + 100% manure, the maximum essential oil percentage from 20 April and 3 June + 100% manure and the maximum chlorophyll (b, total) and essential oil yield from planting date of 3 June and 100% manure application, were obtained.

Based on the results obtained at this experiment, it can be concluded that the 100% manure caused increasing in some morpho-physiological characteristics of Moldavian balm. It seems that manure due to water holding capacity in the soil could have this positive effect on traits. So, since the main reason of medicinal plant cultivation is obtaining their essential oil, so it is recommended that in similar condition, Dracocephalum moldavica L. is cultivated on 3 June with application of 100% manure.