The Effect of Different Nutritional Systems with Nitrogen and Phosphorous Fertilizers on Quantitative and Qualitative Traits of Basil (Ocimum basilicum L.)

Aiming to remove or reduce the chemical input in order to obtain high quality and yield sustainability, plants production in sustainable agriculture. On the other hand, the combined application of chemical and bio-fertilizers can improve yield and quality of medicinal plants. Basil (Ocimum basilicum L.), a member of Lamiaceae family, is an annual plant and is widely used as a vegetable and as an aromatic plant. Considering the importance of medicinal herbs and the global trend for their production and reproduction in sustainable and low-input agricultural systems as well as a lack of research on the response of Basil's medicinal plant to the combined nutritional systems (chemical and biological), the aim of this study was to compare the effects of various nutritional systems with chemical and biological nitrogen and phosphorus fertilizers as high-quality nutrients on some quantitative and qualitative characteristics of Basil. This research was conducted as a factorial experiment based on a completely randomized design with three replications at the Research Center of Faculty of Agriculture, Shahed University, Tehran, in 2014. The experimental factors included nitrogen and phosphorus fertilizer combinations, 100% chemical based on a soil test, 100% biological (for nitrogen, Azotobacter crocococcus and Azospirillium lipophorum, for phosphorus, and Pseudomonas fluorescence) and combining a system of 50% chemical fertilizers with biofertilizers. To provide nitrogen fertilizer from the source of urea containing 46% pure nitrogen and phosphorus fertilizer were used triple superphosphate containing 46% phosphorus oxide (P2O5). Biofertilizers used to provide nitrogen are a mixture of Azotobacter crocum (Azeto-5 strain) and Azopyrillium lipophorum (93 strain), and for phosphorus from the mixture of Pseudomonas putida (P-168 strain) and Pseudomonas fluorescence (P-169 strain), all of which have a concentration 107 CFU/ml provided by the National Institute of Soil and Water Research of Iran. The results showed that different combinations of nitrogen and phosphorus fertilizers and also the interaction between these two had a significant effect on plant height, the number of leaves and shoots yields, percentage, and yield of essential oil. The highest number of leaves per plant was found in treatments N2 × P4 (100% chemical nitrogen with combined of bio-fertilizer and 50% chemical phosphorus) and N4 × P4 (combin of bio-fertilizer and 50% chemical hosphorus combined with bio-fertilizer and 50% chemical nitrogen) respectively with the mean of 54.72 and 54.44 leaves per plant. Interaction of nutrition systems showed that the highest leaves and essential oil yield was in combination N4 × P4 respectively with the average 596.33 kg.ha-1 and 6.56 lit.ha-1. The uses of combination system of nitrogen and phosphorus increased the mean composition of the oils constitutive such as Linalool, Carvacrol and Eugenol compared to control. The results of this study indicate that the use of bio-fertilizers phosphorus and nitrogen, either alone or in combination with 50% chemical fertilizer to improve the quantity and quality of basil had a positive impact. They can, instead of continuous use of chemical fertilizers, be used to optimize the biological inputs for sustainable agriculture and reduce the pollution caused by the use of nitrogen and phosphorous fertilizers.