Evaluation of of yield, essential oil and productivity indices in different planting combinations in the intercropping of hyssop (Hyssopus officinalis) and lentil (Lens culinaris)

Intercropping can be considered as one of the ways to increase yield and sustainability of production per unit area. Also, medicinal plants play an important role in human health in the world. Many people in different countries of the world tend to use these drugs. The need for these plants is increasing due to the production of herbal medicines and cosmetics in the national and international markets. Therefore, improve quality of natural medicinal plants is an absolute necessity. In order to improvement of soil fertility and hyssop (Hyssopus Officinalis) guality by biological nitrogen fixation with bacteria is known by lentil (Lens culinaris), the experiment was conducted to evaluate the different combinations of intercropping hyssop and lentil. The experiment was performed in 2016, based on randomized complete block design with three replications in the Research Field of Imam Khomeini International University, Qazvin, Iran. The experimental treatments includes: pure culture of hyssop (A), pure culture of lentil (B), 100% hyssop + 25% lentil (C), 100% hyssop + 50% lentil (D), 100% lentil + 25% hyssop (E) and 100% lentil + 50% hyssop (F). The results of this study showed that the highest dry weight of hyssop per unit area was obtained from its pure culture (A) and 100% hyssop + 25% lentil (C). The highest content of hyssop essential oil (without statistical difference) was obtained from 100% hyssop + 25% lentil (C) and 100% hyssop + 50% lentil (D). Means comparison of hyssop essential oil yield per unit area showed that the pure culture of hyssop (A) and 100% hyssop + 25% lentil (C) had the maximum amounts without statistical difference. The yield of lentil in its solecropping treatment showed the highest value, which showed a significant difference with different intercropping treatment. The lowest yield of lentil per unit area was obtained from treatment C (25% lentil + 100% hyssop), which showed a significant difference with other treatments. Also, the results of mean comparisons showed that D treatment (100%hyssop + 50%lentil) had the highest 1000-grain weight, which was subjected to B (sole cropping of lentil) and C (25% lentil + 100% hyssop) treatments in the same statistical group. Comparison of mean values showed that sole cropping (A) and 100% lentils + 25% hyssop (E) had the highest leaf nitrogen content and lentil solecropping (B) had the highest nitrogen content in lentil seed.The comparison of Land Equivalent Ratio (LER) showed that all mixing ratios of hyssop and lentil (with the exception of 100% lentil + 50% hyssop - F) had the LER>1 which shows the lead of intercropping to pure culture. It should be noted that treatments C (100% hyssop + 25% lentil) and D (100% hyssop + 50% lentil) had the highest LER. Overall, the results showed that the intercropping of hyssop and lentil could stabilize the production by improving the use of resources. Also it could be significantly effective by reducing the consumption of chemical inputs with nitrogen fixation towards the ecological production of medicinal plants.