The effects of the irrigation regime and different fertilizer sources on the eco-physiological responses and yield characteristics of dragon’s head were explored in a factorial experiment based on a randomized complete block design with 12 treatments and 3 replications in the 2019 growing season. The treatments included six different fertilizer sources (animal manure, vermicompost, poultry manure, biofertilizer, chemical fertilizer, and control) and two irrigation regimes (rainfed and supplemental irrigation). The results indicated the positive effects of supplementary irrigation and the application of vermicompost, poultry manure, and animal manure by increasing the absorption of nutrients (phosphorus and potassium) and improving relative water contents, chlorophyll and carotenoid contents, and the fixed oil percentage of dragon’s head. The activities of catalase, ascorbate peroxidase, and superoxide dismutase decreased in the rainfed plants, whereas organic fertilizer application increased the antioxidant enzyme activity. The highest grain yield (721 kg ha⁻¹), biological yield (5858 kg ha⁻¹), total flavonoids (1.47 mg g⁻¹ DW), total phenol (27.90 mg g⁻¹ DW), fixed oil yield (200.17 kg ha⁻¹), and essential oil yield (1.18 kg ha⁻¹) were noted in plants that were treated with vermicompost under supplemental irrigation. Therefore, it is recommended that organic fertilizers such as vermicompost and poultry manure be used to substitute chemical fertilizers. These practices can help popularize organic crops using rainfed and supplementary irrigation.

Since chemical fertilizers pollute soil, water and crops, conscientious agricultural producers seek alternatives to chemical fertilizers. Biological fertilizers are considered a reliable alternative for improving soil productivity and plant growth in sustainable agriculture. The response of some agrobiological and antioxidant properties of Syrian cephalaria (Cephalaria syriaca L.) to different fertilizer sources was explored in an experiment which included: (i) mycorrhiza + manure; (ii) mycorrhiza + vermicompost; (iii) mycorrhiza + Azotobacter; (iv) mycorrhiza + chemical fertilizer; (v) mycorrhiza; and (vi) control. The results showed that the highest seed yield, biological yield, oil percentage yield, were observed in plants treated with mycorrhiza + vermicompost, whereas the highest 1000-seed weight was obtained from the application of mycorrhiza + manure. With respect to photosynthesizing pigments, the application of mycorrhiza + vermicompost increased chlorophyll a, chlorophyll b, total chlorophyll, carotenoid content as well as total phenols, total flavonoids and DPPH antioxidant activity as compared to control (unfertilized) plants. The mixed application of different fertilizer sources influenced the uptake of trace elements (Fe, Zn and Cu) optimally. In the light of the obtained results for the agrobiological and antioxidant properties of Syrian cephalaria, in most of the measured traits, there is no significant difference between manure, vermicompost and chemical fertilizers in combination with mycorrhiza. Hence the use of organic and biological inputs instead of chemical fertilizer for improving crop efficiency and quality with the aim of alleviating pollution and accomplishing sustainable agriculture is highly encouraging.

Medicinal plant production is most important than other agricultural plants due to their phytochemical compounds effects on human health. Paying attention to plant nutrition requirement is so important. In order to assess the effect of nitrate (NO₃⁻) dosage supplies from two types of fertilizers on growth and phytochemical properties of Echinacea purpurea rhizomata cum radicibus, an experiment with completely simple design was carried out under greenhouse conditions. Two types of fertilizers (new invented nitrogen (N) slow release fertilizer and urea chemical fertilizer) at three dosages (50, 100, and 150 mM) were applied. Plant growth parameters and total phenolic (TPC), total flavonoids (TFC), polysaccarides content, essential oil content, caffeic acid derivatives, and anti-radical scavenging activities of E. purpurea were assessed. The results showed the significant (p ≤ 0.01) differences among treatments, both in growth and phytochemical properties. Using of N slow release, especially in 150 mM dosage, significantly increased all the plant growth and phytochemical properties. The dried E. purpurea rhizomata cum radicibus contained more caftaric acid (max 12.56 mg g⁻¹ DW) and chicoric acid (max 7.56 mg g⁻¹ DW) than other derivatives. Despite the impact of heavy metals on yield and growth of E. purpurea, the concentration of all heavy metals and micronutrients (boron (B), cadmium (Cd), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), nickel (Ni), lead (Pb), and zinc (Zn)) in studied soil and fertilizer samples was less than United States Environmental Protection Agency (USEPA) limits of contamination. Based on the results, using of N slow release fertilizers can improve phytochemical properties of the plant due to its polymeric structure and can be a suitable substitution of chemical fertilizers, especially in medicinal plants growth.

This study investigated the effect of organic fertilizers on vegetative growth and the physiological and antioxidant activity characteristics of thyme plants grown under stress. A factorial experiment was conducted according to randomized complete block design with 12 combinations and 3 replications in the 2018 growing season. The experiment factors were the implementation of organic fertilizers at 4 levels (vermicompost, manure compost, animal manure, and control) and irrigation regime at 3 levels (Irr1, Irr2, and Irr3, respectively, irrigation after 60, 90, and 120 mm evaporation from A pan). The results showed that With delayed irrigation, the chlorophyll a and b contents, total chlorophyll, and carotenoid decreased, while the application of low water stress enhanced the amount of oil and the oil yield with the respective highest values of 2.61% and 3.68 g/m under mild stress conditions. Nonetheless, higher values for the aforementioned properties were noted with the application of vermicompost. Water deficit decreased nutrient uptake (K, P, and N) and relative water content, biological yield, and seed yield of thyme, indicating that thyme was sensitive to drought, and organic fertilizers application improved nutrient uptake (K, P, and N) and relative water content, biological yield and seed yield of the plant within irrigation levels. The activities of catalase, superoxide dismutase and ascorbate peroxidase were reduced under organic fertilizers such as vermicompost and manure compost as compared with control under drought stress. The plants of thyme showed a good response to organic fertilizers under water deficit circumstances, with vermicompost being the most effective.

Balangu (Lallemantia sp.) is a medicinal herb with a variety of applications, all parts of which have economic uses, including leaf for extraction of essential oils, as a vegetable and potherb, seed for extraction of mucilage and edible or industrial oil. To investigate the effect of cultivation season and standard chemical and nano fertilizers (n) on the yield components and antioxidant properties of Dragon’s head, a factorial experiment based on randomized complete block design was conducted with 12 treatments and three replications. Experimental treatments consisted of two seasons (spring and winter cultivation) and six levels of fertilizer (control, NPK-s, NPK-n, Fe-chelated-n, NPK-n + Fe-chelated-n, NPK-s + NPK-n + Fe-chelated-n). The traits included grain yield per plant, essential oil percentage and yield, mucilage percentage and yield, antioxidant properties in the seeds and leaves, including total phenols and flavonoids content, DPPH radical scavenging, and nitric oxide and superoxide radical scavenging. The results showed that winter cultivation had a noticeable advantage over spring cultivation across all of the traits. The highest grain yield per plant was obtained in winter cultivation using NPK-n + Fe-chelated-n fertilizer treatment. The highest essential oil percentage was in NPK-n + Fe-chelated-n. The highest mucilage percentage was observed in NPK-s + NPK-n + Fe-chelated-n fertilizer treatment, which was not statistically different to NPK-n + Fe-chelated-n treatment. The combined effects of winter cultivation and NPK-n + Fe-chelated-n fertilizers resulted in improving antioxidant activity traits. Overall, the results indicated that the combination of winter cultivation and NPK-n + Fe-chelated-n fertilizers are the most appropriate treatment to acquire highest qualitative and quantitative yield of Dragon’s head, in the Azerbaijan region (Iran).