عنوان مقاله [English]
Salvia leriifolia Benth. (Nowruzak) is a herbal plant from Lamiaceae family, which is exclusively native of Iran and Afghanistan. Existence of this species is reported in Khorasan and Semnan provinces of Iran. As extreme pressure of grazing and harvesting the nature has put this species at risk of extinction, and on the other hand this plant has numerous herbal values and its cultivation can produce the market needs as well as preserve it from extinction. Therefore its domestication is now a priority and optimized nutrition for cultivated plants is one of the important factors in quality and quantity enhancement of the product. The aim of this research was to study the effect of three main nutrient: nitrogen, Phosphor, and potassium (NPK) on growth of Nowruzak and measure its morphological reactions to these elements in the poor soil of its habitat.
Materials and methods
To study the effect of different nutritious elements on quantitative properties of Nowruzak, a factorial experiment was conducted as randomized complete block design with three replications in the Research Field of Islamic Azad University of Gonabad in March 2014. In this experiment, nitrogen fertilizers in three levels (N1= control, N2=100 kg.ha-1 and N3=200 kg.ha-1 based on net nitrogen), Phosphor in three levels (0, 50 and100 kg.ha-1 based on P2O5) and potassium fertilizers in two levels (0- and 50 kg.ha-1 based on K2O) were applied of farm to specify the effect of each elements and their reactions on quantitative growth properties of Nowruzak.
Results and discussion
Results show that the effect of different levels of nitrogen fertilizer on plant height, harvest index, cover crown diameter and number of fertile branches are significant at 1% level. In a way that levels of nitrogen fertilizer are placed in first, second and third group of Duncan multiple range test, respectively. The highest plant height with average of 41.97 cm is assigned to 200 kg net nitrogen . Moreover, application of 200 kg.ha-1 of net nitrogen led to highest cover crown diameter with average of 92.07 cm and led to increase the number of fertile branches with average of 31.75 per plant. The same trend as nitrogen observed for different levels of phosphorous. Application of 100 kg Phosphor resulted highest number of leaves with average of 140 leaf/plant. The highest plant height is also assigned to the group of 100 kg Phosphor fertilizer with average of 41.97 cm. Moreover application of this amount of fertilizer led to highest cover crown diameter (94.06 cm) which also resulted in increase of the number of fertile branches (average: 33.21 branches per plant).
The results of analysis of variance regarding potassium fertilizer show that its application has significant effect on all the measured parameters at 1% level. Application of 50 kg of potassium fertilizer, in comparison with no application, results in increase of the number of leaves (average: 122 per plant), plant height (average: 37.06 cm), cover crown diameter (average 78.13 cm) and the number of fertile branches (average 26.55). The obtained results show that Bajestan ecotype of Nowruzak showed an acceptable adaptability to fertilizer application in Gonabad city which indicated the poorness of the soil.
As chemical fertilizers are among the main factors of soil fertilization, Nowruzak medicinal plant showed a normal response to highest amount of applied fertilizers, therefore it is justified to apply chemical fertilizers in cultivation of this plant in the field to increase the plant size which is the economically valuable trait