Extended Abstract Introduction: Intercropping is a vital strategy in sustainable agriculture; it enhances production sustainability by improving both the yield and quality of crop plants. This strategy increases biodiversity and capitalizes on the interactions among different plant species, including their morphological and ecophysiological differences. Such diversity can lead to more efficient use of resources, reduced production costs, and ultimately, an increase in net farm income. The integration of legumes in intercropping systems is particularly beneficial, as these species have the ability to fix atmospheric nitrogen, enriching the soil and supporting the growth of neighboring plants from a different crop species like dill (Anethum graveolens L.). This study aims to identify the optimal mixed treatment combinations for dill, focusing on both grain yield and essential oil yield in intercropping versus monoculture systems. By systematically evaluating various intercropping treatments, the research seeks to uncover the most effective plant combinations that enhance the performance of dill as an edible vegetable. The findings will not only contribute to the understanding of sustainable agricultural practices but provide also practical recommendations for farmers, promoting the adoption of intercropping systems that can lead to improved ecological benefits and economic viability in farming. Materials and Methods: In order to achieve the most appropriate planting combination in terms of spatial arrangement and to investigate its effects on yield, yield components, as well as the percentage and efficiency of essential oil, an experiment was conducted using a randomized complete block design with seven treatments and three replications at the Research Farm of the Faculty of Agriculture, University of Tabriz, Tabbriz, northwest Iran. The different cultivation patterns included a pure stand and six mixed cultivation patterns of the two plants, comprising three additive ratio patterns (1:20, 1:40, and 1:60) and three replacement ratio patterns (1:1, 1:2, and 1:3). Results and Discussion: The results of the study revealed that dill plants cultivated in various mixed cropping patterns exhibited remarkable performance, particularly in the 1:20 and 1:60 planting ratios. These specific intercropping arrangements resulted in the highest inflorescences/plant, indicating a strong reproductive capacity that is essential for maximizing seed production. Additionally, these ratios also led to an increased grains/plant, which is a critical factor for final grain yield. The biological yield, which encompasses the total biomass produced, was also significantly enhanced in these mixed cropping patterns, suggesting that the synergistic interactions between the crops in these ratios contributed positively to growth and productivity. Moreover, the study found that the percentage and yield of essential oil were significantly influenced by the different mixed cropping patterns. The 1:20 and 1:60 ratios not only yielded the highest essential oil content but consistently performed well also across all three stages of oil extraction: flowering, milky, and maturity. This finding underscores the importance of selecting appropriate intercropping ratios to optimize essential oil production. Among the three stages of oil extraction, the milky stage emerged as the most productive, yielding the highest essential oil quantity. This stage is characterized by the plant’s investment in the grain constituents, which likely enhances the biosynthesis of essential oil compounds. These insights suggest that schedueling the harvest to coincide with the milky stage can significantly benefit essential oil yield, providing valuable information for farmers aiming to maximize both grain and oil production in dill cultivation. Taken to gether, the findings highlight the advantages of utilizing specific mixed cropping patterns, particularly the 1:20 and 1:60 ratios, to enhance the agronomic and economic viability of dill as an edible and aromatic crop. This research not only contributes to the understanding of intercropping benefits but offers also practical recommendations for farmers seeking to improve their production practices through sustainable agricultural methods. Conclusions:Our findings suggest that intercropping can significantly enhance dry matter accumulation and improve the overall quality of dill products. This strategy can result in a more efficient use of land and resources, ultimately contributing to higher yields compared to monoculture systems. The specific observation that the 1:1 treatment and sole cropping demonstrated favorable performance in dry matter accumulation indicates that there is a potential for both mixed and single cropping systems to be effective. The 1:1 ratio suggests a balanced competition between the two species, allowing them to complement each other’s growth requirements. In this scenario, both dill and fenugreek can benefit from shared resources while minimizing competition, leading to enhanced growth and productivity.
Extended Abstract Introduction: Cadmium, a heavy and hazardous metal with an atomic number of 48, is increasingly disseminated in agricultural soils and negatively affects plants due to its high solubility in water. The toxic distribution of this element in soils and plants leads to reduced germination, impaired plant growth, and diminished activities of antioxidant enzymes. Marigold, belonging to the Asteraceae family, possesses the ability to absorb cadmium from contaminated soils and is recognized as an ornamental and medicinal plant. Furthermore, employing seed priming techniques can enhance the plant's resistance to environmental stresses, including cadmium exposure. This study investigates the effects of marigold seed pre-treatment on growth, physiological traits, and antioxidant activity under cadmium stress conditions. Materials and Methods: To investigate the effects of marigold seed pre-treatment on growth and biochemical characteristics under cadmium stress conditions, a factorial experiment was conducted in a completely randomized design with three replicates at the Agricultural Higher Education Center in Bardseer, southest of Iran. The study included two factors: varying cadmium levels (0, 30, 40, and 60 mg/kg of soil) and four types of seed priming (beeswax pomace, vermicompost, cordia fruit extract, and no priming). To prepare organic extracts, dried and ground materials were mixed with distilled water and filtered after 48 h on a shaker. Seeds were soaked in these extracts for 12 hours before being sterilized and sown. The dry weight of aerial organs was measured, and biochemical characteristics such as phenolic content, anthocyanins, proline, protein, chlorophyll, carotenoids, and antioxidant enzyme activities were assessed. Analysis of variance was performed using SAS software, and mean comparisons were conducted using the LSD test. Results: The results indicated that increasing levels of cadmium stress significantly decreased the leaves/plant, flowers/plant, dry flower weight, dry plant weight, concentration of chlorophyll, protein, and soluble sugars, and catalase enzyme activity in marigold plants. However, cadmium stress elevated the content of the guaiacol peroxidase enzyme, anthocyanins, phenols, and proline concentrations. The effects of priming with different organic materials yielded varying results across different traits, with the effects of vermicompost extract and beeswax pomace being more pronounced compared to tamarind extract. Additionally, as the severity of cadmium stress increased, the positive role of seed priming in mitigating negative stress effects became more evident. Particularly, at the stress level of 60 mg of cadmium per kg of soil, seed priming using vermicompost and beeswax resulted in approximately 66% and 54% increases in mean plant dry weight, respectively, compared to the control, while at the stress level of 40 mg, the increases were 12% and 7%, respectively. However, under non-stress conditions and at the 60 mg per kg cadmium stress level, priming did not affect chlorophyll content. Seed priming with organic materials, especially vermicompost and beeswax pomace, exerted different influences on the activities of GPX and catalase antioxidant enzymes under both stress and non-stress conditions. Under non-stress treatment, priming did not affect guaiacol peroxidase enzyme activity; however, at cadmium stress levels of 30 and 60 mg per kg, seed priming with vermicompost yielded higher guaiacol peroxidase enzyme activity compared to the control and other treatments. At the stress level of 40 mg of cadmium per kg, no significant differences were observed among the seed priming with vermicompost, beeswax, and cordia extract compared to the control. Meanwhile, the application of all three priming extracts (vermicompost, beeswax, and cordia) significantly increased catalase enzyme activity across all levels of cadmium stress, with seed priming using vermicompost and, to a lesser extent, beeswax pomace producing higher catalase enzyme levels than the control and other treatments. In this study, soluble sugar content increased under all three cadmium stress levels with the application of priming materials, with vermicompost and, to a lesser extent, beeswax pomace showing the best effects among the priming treatments. Furthermore, beeswax and vermicompost extracts led to a 44% increase in phenolic content in marigold plants under 30 and 40 mg per kg cadmium stress conditions. Conclusion: The results of this study indicate that cadmium, as a heavy metal, has detrimental effects on the growth and biochemical attributes of marigold plants. According to the data obtained, increasing levels of cadmium resulted in a significant reduction in the leaves/plant, flowers/plant, dry flower weight, dry plant weight, chlorophyll and protein concentrations. However, cadmium stress led to an increase in the activity of antioxidant enzymes such as guaiacol peroxidase, as well as anthocyanins and phenols concentrations. Seed priming with organic materials, particularly vermicompost and beeswax pomace, significantly enhanced the plant's resistance to cadmium stress. At high levels of cadmium, these methods contributed to increased plant dry weight and enhanced antioxidant enzyme activities. Particulrlly, seed priming with vermicompost and beeswax pomace demonstrated greater efficacy in alleviating the negative effects of cadmium, allowing these methods to significantly maintain plant health under stress conditions through increased antioxidant activity and osmotic regulation. Therefore, these seed pre-treatment methods have the potential to be incorporated into agricultural optimization programs to enhance plant resistance to environmental stresses, particularly those arising from heavy metal contamination.
