Influence of Nitrogen Sources Applied by Fertigation to an Enriched Soil with Organic Compost on Growth, Mineral Nutrition, and Phytochemicals Content of Coriander (Coriandrum sativum L.) in Two Successive Harvests

Elemental Profiling and Safety Assessment of Four Spice Vegetables: Insights into Nutritional and Toxicological Implications

Spiced vegetables are consumed globally, appreciated for their distinctive aromas and flavor profiles. Additionally, their unique elemental composition is recognized as a crucial parameter. This study aimed to evaluate the safety and toxicological risk of four commonly consumed spice vegetables: garlic (Allium sativum), ginger (Zingiber officinale), green onion (Allium fistulosum), and chili pepper (Capsicum annuum). Using ICP-OES and ICP-MS, a total of 25 elements, including macro, trace, and toxic elements, were determined. The analytical methods were validated per AOAC guidelines. Results indicated that potassium was the most abundant element across all samples, with garlic showing significantly higher concentrations of phosphorus, sulfur, and potassium. Trace element analysis revealed zinc and manganese as the most prevalent, with ginger exhibiting elevated levels of manganese, barium, and gallium. While toxic elements were detected in all samples, their concentrations remained within safe limits for human consumption. The estimated daily intake (EDI) and hazard quotient (HQ) analysis, based on Korean dietary data, confirmed minimal health risks. Heatmap analysis and linear discriminant analysis plots demonstrated the potential to distinguish between the four spice vegetables based on element profiles. This study highlights the importance of monitoring elemental compositions in spice vegetables to ensure food safety and reduce health risks from toxic elements, offering crucial insights into their nutritional value and safety.

Exploring Sustainable Fertilization Strategies Involving Biochar, Compost, and Inorganic Nitrogen: Impact on Nutrient Uptake, Yield, Phytochemical Accumulation, and Antioxidant Responses in Turnips

The effect of fertilization strategies involving biochar, compost, and inorganic N on growth and phytochemical accumulation in turnips was studied in a greenhouse pot experiment. The experiment was carried out with six fertilizer treatments: unfertilized soil (US), compost (120 g/pot) + biochar (20 g/pot) (C + B), compost (120 g/pot) + 0.5 g N/pot (C + 0.5 N), biochar (20 g/pot) + 0.5 g N/pot (B + 0.5 N), compost (120 g/pot) + biochar (20 g/pot) + 0.5 g N/pot (C + B + 0.5 N), and inorganic fertilization (pre-plant mineral fertilizer + 1 g N/pot (PF + N)). Compost, biochar, and pre-plant mineral fertilizer were incorporated into the top 10 cm of soil, while inorganic N was applied weekly in equal amounts. The application of biochar with C + 0.5 N, compared to C + 0.5 N alone, reduced plant Ca and Mg uptake but did not affect dry biomass production. Using compost + 0.5 N, with or without biochar, proved to be a viable and sustainable strategy, achieving high dry biomass yields similar to inorganic fertilization but with lower inorganic N and no addition of the other inorganic nutrients. The biomass increase was due to enhanced nutrient uptake, resulting from the synergy between compost and the application of a reduced amount of N. The co-applications reduced nitrate levels in both shoots and roots and left the soil more fertile than soil fertilized with inorganic fertilization. Fertilization strategies differently affected the accumulation of ascorbic acid, total phenols, polyphenol oxidase, and proline in roots and shoots. Inorganic fertilization enhanced ascorbic acid and total phenols in shoots, while the combination of compost, biochar, and 0.5 N was more effective in roots, suggesting that fertilization strategies should be tailored to tissue-specific goals.

Substrate composition evaluation for urban green infrastructure planted with calcareous grassland dicotyledonous species

Green roofs and walls offer many benefits, not only in terms of the ecosystem services, but also in terms of improving building performance. The growing medium is the most important component of green roofs and walls. It should ensure stable plant growth with minimal maintenance and the proper choice is crucial for the survival and performance of the vegetation. In the study, we investigated how the source and supply of nutrients affects plant performance in a designed substrate for green walls and roofs. Topsoil from the site of plant origin mixed with sand and compost supplemented with mineral fertilizer was used to study the growth of Trifolium medium L. and Potentilla reptans L., element contents, oxidative stress level and photosynthetic efficiency. P. reptans was in most cases insensitive to mineral fertilization, but an adequate dose of compost improved its growth. T. medium was very sensitive to excessive mineral fertilization, which significantly impaired the growth and physiological status of the plants. Compost as the sole source of additional nutrients in a topsoil-based substrate seems to be the appropriate choice when legumes are used in a green wall or green roof. From the results obtained, we can conclude that calcareous grassland species can be successfully used in designing of green urban infrastructure.

Growth, productivity and phytochemicals of Coriander in responses to foliar application of Acacia saligna fruit extract as a biostimulant under field conditions

The application of natural extracts to vegetable plants can increase production, optimize nutrient and water uptake, and mitigate the effects of stress on vegetable plants by enhancing primary and secondary metabolism. In this study, Acacia saligna (Labill.) H.L.Wendl. fruit aqueous extract (FAE) was applied as a foliar application to assess and demonstrate its effects on growth, productivity, and phytochemicals of coriander (Coriandrum sativum L.) plants. A. saligna FAE (2%, 4%, and 6%), each combined with 50% of the recommended dose of N fertilizer was applied to coriander plants over the course of two successive seasons in the field. These treatments were compared with the control treatment, which used a 100% recommended dose of N. The four tested treatments were set up in a randomized complete block design with three replicates for a total of 12 experimental plots. Each replicate (experimental plot) was 3 m2 (2 × 1.5 m2) in size and included 300 seeds/m2. The phytochemicals were examined using chromatographic and spectrophotometric methods, where the essential oils (EOs) extracted from leaves were analyzed by Gas chromatography-mass spectrometry (GC-MS), while the phenolic and flavonoid compounds were analyzed by High Performance Liquid Chromatography (HPLC). With the application of A. saligna FAE (4%) + 50% N fertilizer, the levels of total solid content, total carbohydrates, total protein, total phenols, and total antioxidant activity, as well as chlorophyll a, chlorophyll b, chlorophyll a + b, and carotenoids, were increased at harvest. The treatment A. saligna FAE at 6% + 50% N fertilizer did not observe significant improvement in the growth parameters of coriander plants because of the anticipated allelopathic effects. By GC-MS analysis, the major compounds in the EO from control treatment were 2-octyn-1-ol (23.93%), and 2-butyl-1-octanol (8.80%), in treated plants with 2% of A. saligna FAE + 50% N fertilizer were (E)-2-decen-1-ol (32.00%), and 1-methoxymethoxy-oct-2-yne (13.71%), in treated plants with 4% A. saligna FAE + 50% N fertilizer were E-2-undecen-1-ol (32.70%), and 3,5,5-trimethyl-1-hexene (8.91%), and in the treated plants with A. saligna FAE (6%) + 50% N fertilizer were phytol (80.44%), and (Z)6,(Z)9-pentadecadien-1-ol (13.75%). The flavonoid components 7-hydroxyflavone, naringin, rutin, quercetin, kaempferol, luteolin, apigenin, and catechin were presented with variable concentrations according to the treatments utilized as identified by HPLC analysis from the methanol extracts of the treated plants with the combination treatments of A. saligna FAE (2, 4, and 6%) and N fertilization (50% from the recommended dose) and control coriander plants (100% N recommended dose). The combination of 50% N fertilizer treatment and the biostimulant A. saligna FAE (4%) seems to improve coriander plant growth while simultaneously lowering N fertilizer consumption. Future research will be needed to further study the effectiveness of several concentrations of A. saligna FAE in various conditions and/or species.

Effect of Preharvest Ethephon Application on Selected Biochemical Components and Polyphenol Oxidase Activity in Macadamia Nuts

Ethephon is a plant growth regulator that triggers diverse responses in plants, such as fruit ripening, leaf senescence, hull senescence, stem elongation, and nut abscission. This study examined how the preharvest application of ethephon 480 SL® affects selected biochemical components and polyphenol oxidase (PPO) activity in two macadamia nut cultivars: '788' and 'Beaumont'. Ethephon was applied to the trees via a Cima mist blower at rates of 13.33 mL/L per hectare for the '788' cultivar and 16.67 mL/L per hectare for the 'Beaumont'. Following harvest, the nuts were stored at 25 °C for 72 days, and samples were taken at 18-day intervals. Standard procedures were used to assess the following: total phenolics, total flavonoids, 2,2,-diphenyl-1-picrylhydrazyl (DPPH) assay, Ferric reducing ability power (FRAP) assay, sucrose, total protein, and PPO activities. This evaluation was carried out across a total of four treatments: ethephon-treated nuts from the orchard floor (ED), ethephon-treated nuts from the tree (ET), untreated nuts from the orchard floor (CD), and untreated nuts from the tree (CT). The evaluation's outcomes were analyzed using a principal component analysis (PCA), a correlation matrix heat map (CMHM), and a graphical assessment. The results unveiled significant correlations and associations among the assessed parameters. The correlation matrix heat map analysis highlighted a strong positive correlation (0.97) between the sucrose and the PPO activity in the 'Beaumont' cultivar, supported by the PCA analysis identifying the ED treatment as the most influential. At the storage period's conclusion, the ED treatment had the highest sucrose content (18.63 mg/g) and polyphenol oxidase activity (1.06 U g-1). In the '788' cultivar, a close relationship emerged between the phenolic content, the PPO activity, and the Ferric reducing antioxidant power (FRAP)'s antioxidant activity. Consistently, the CT treatment (untreated nuts) demonstrated positive correlations with several key parameters in both cultivars, displaying heightened phenolic content and antioxidant activities. Consequently, our findings indicate that the CT treatment, involving tree-harvested nuts without ethephon application, could be the preferred option for sustaining macadamia nuts' quality and shelf life compared to other methods. Moreover, our study underscores the significance of proper storage conditions for maintaining the desired biochemical parameters of macadamia nuts. By comprehending the effects of distinct treatments and harvesting techniques, producers and processors can devise strategies to optimize storage conditions and uphold macadamia nut quality.

Growth, Yield and Photosynthetic Performance of Winter Wheat as Affected by Co-Application of Nitrogen Fertilizer and Organic Manures

The application of organic manures was found to be beneficial, however, the integrated use of organic manures with chemical nitrogen fertilizers has proven more sustainable in increasing the photosynthetic attributes and grain yield of the winter-wheat crop. A multi-factor split-plot design was adopted, nitrogen and manure fertilizer treatments were set in the sub-plots, including nitrogen-gradient treatment of T1:0 kg N ha⁻¹, T2:100 kg N ha⁻¹, T3:200 kg N ha⁻¹, and T4:300 kg N ha⁻¹ (pure nitrogen -fertilizer application) The 25% reduction in nitrogen combined with the manure-fertilizer application includes T5:75 kg N ha⁻¹ nitrogen and 25 kg N ha⁻¹ manure, T6:150 kg N ha⁻¹ nitrogen and 50 kg N ha⁻¹ manure, and T7:225 kg N ha⁻¹ nitrogen and 75 kg N ha⁻¹ manure. The maximum results of the total chlorophyll content and photosynthetic rate were 5.73 mg/g FW and 68.13 m mol m⁻² s⁻¹, observed under T4 in Zhongmai 175, as compared to Jindong 22 at the heading stage. However, the maximum results of intercellular CO₂ concentration were 1998.47 μmol mol⁻¹, observed under T3 in Jindong 22, as compared to Zhongmai 175 at the tillering stage. The maximum results of LAI were 5.35 (cm²), observed under T7 in Jindong 22, as compared to Zhongmai 175 at the booting stage. However, the maximum results of Tr and Gs were 6.31 mmol H₂O m⁻² s⁻¹ and 0.90 H₂O mol m⁻² s⁻¹, respectively, observed under T7 in Zhongmai 175 as compared to Jindong 22 at the flowering stage. The results revealed that grain yield 8696.93 kg ha⁻¹, grains spike⁻¹ 51.33 (g), and 1000-grain weight 39.27 (g) were significantly higher, under T3 in Zhongmai 175, as compared to Jindong 22. Moreover, the spike number plot⁻¹ of 656.67 m² was significantly higher in Jindong 22, as compared to Zhongmai 175. It was concluded from the study that the combined application of nitrogen and manure fertilizers in winter wheat is significant for enhancing seed at the jointing and flowering stages. For increased grain yield and higher economic return, Zhongmai 175 outperformed the other cultivars examined. This research brings awareness toward the nitrogen-fertilizer-management approach established for farmers’ practice, which might be observed as an instruction to increase agricultural management for the winter-wheat-growth season.