Iron (Fe) is required for most metabolic processes, including DNA synthesis, respiration, photosynthesis, and chlorophyll biosynthesis; however, Fe deficiency is common in arid regions, necessitating additional research to determine the most efficient form of absorbance. Nano-fertilizers have characteristics that are not found in their traditional equivalents. This research was implemented on Washington navel orange trees (Citrus sinensis L. Osbeck) to investigate the effect of three iron forms—nano (Fe-NPs), sulfate (FeSO₄), and chelated (Fe-chelated)—as a foliar spray on the growth, fruiting aspects, and nutritional status of these trees compared to control. The highest values of the tested parameters were reported when the highest Fe-NPs level and the highest Fe-chelated (EDTA) rate were used. Results obtained here showed that the spraying of the Washington navel orange trees grown under similar environmental conditions and horticulture practices adopted in the current experiment with Fe-NPs (nanoform) and/or Fe-chelated (EDTA) at 0.1% is a beneficial application for enhancing vegetative growth, flower set, tree nutritional status, and fruit production and quality. Application of Fe-NPs and Fe-chelated (EDTA, 0.1%) increased yield by 32.0% and 25% and total soluble solids (TSS) by 18.5% and 17.0%, respectively, compared with control. Spraying Washington navel orange trees with nano and chelated iron could be considered a significant way to improve vegetative growth, fruit production, quality, and nutritional status while also being environmentally preferred in the arid regions.

Nano fertilization is a precision approach to sustain economically viable and environmentally compatible crop production. The objective of our study was to evaluate the effects of different sources and rates of iron (Fe) fertilization as an essential micronutrient on the growth, physiological processes, and yield of greenhouse-grown tomatoes (Solanum lycopersicum cv. Bigdena F1). A factorial experiment in randomized complete block design with four replications was conducted using three sources (Conventional, FeCl_3.6H₂O [Conv-Fe]; Chelated with 6% Fe [Che-Fe]; and Nano Fe₂O₃ [Nano-Fe], alpha, 99%, 30–50 nm) and rates of Fe (0, 50, and 100 mg/kg soil) during 2015 and 2016 growing seasons. Averaged across Fe rates, the Nano-Fe significantly increased plant height, leaf number and area, shoot and root fresh and dry weights, and Soil Plant Analysis Development (SPAD) readings. Nano-Fe at 100 mg/kg significantly increased plant height, leaf number and area, fresh and dry weights of shoot and roots, gas exchange parameters i.e., photosynthesis (Pn), stomatal conductance (gs) and transpiration (E) rates, total yield, and yield components of tomatoes in comparison to the other rates. While there were no significant simple and interactions of Fe on plant physiological processes, the Nano-Fe had the highest Pn with an associated decrease in E and an increase in gs. Nano-Fe, when applied at 100 mg/kg, produced the highest fruit diameter, fruit numbers/plant, total fruit weight/plant, mean fruit weight/plant, total fruit numbers/ha, and total fruit weight/ha, followed by Nano-Fe at 50 mg kg as compared with other Fe sources and rates. In conclusion, Nano-Fe fertilization is more effective than Conv-Fe and Che-Fe fertilizations across growing seasons to improve growth characteristics and metabolic processes of tomato plants, as Fe plays an important role in photosynthates accumulation and translocation. Nano-Fe increased tomato yield by 11% compared to Conv-Fe and Che-Fe fertilizers and will greatly improve farmers’ profitability.

Sweet pepperincludes several vitamins and is regarded as a great source of bioactive nutrients, such as carotenoids and phenolic compounds, for human growth and activities. This work aimed to investigate the effects of the soil addition of growth stimulants, namely, effective microorganisms (EM), compost tea, fulvic acid, and yeast extract, and foliar applications of seaweed extract, on the vegetative growth, enzyme activity, phytohormones content, chemical constituents of plant foliage, fruit yield, and fruit quality of sweet pepper plants (Capsicum annuum L. cv. Zidenka) growing under greenhouse conditions. The results showed that the tallest plant, largest leaf area/plant, and heaviest plant fresh and dry weights were recorded after combining a soil addition of yeast extract and foliar spray with seaweed extracts at 3 g/L in two growing seasons. The highest number of fruit/plant, fruit yield/m², fruit values of vitamin C (VC), total sugars, total soluble solids (TSS), and carotenoids, along with the highest leaf of cytokines, P, K, Fe, and total carbohydrates values, were obtained using a soil addition of fulvic acid and spray with seaweed extract at 3 g/L in the two seasons of study. These treatments also provided the lowest abscisic acid, peroxidase, and super oxidase dismutase values in the same conditions. Sweet pepper plants supplemented with compost tea and seaweed extract foliar spray at 3 g/L were the most promising for inducing the highest values of fruit fresh and dry weights, fruit length and diameter, and the leavesrichest in N, Zn, and Mn; inversely, it induced the lowest catalase levels in both seasons. The applications of EM, yeast extract, and seaweed extract could be applied for high growth, mineral levels, enzymatic activity, fruit yield, and nutritional value of sweet pepper fruit and minimizing environmental pollution.

Broccoli is a popular vegetable throughout the world and contains important nutritional features. This study was conducted to evaluate the effect the fertilization with different phosphorus sources (i.e., soil application of rock phosphate (RP) at 428 kg ha⁻¹, calcium superphosphate (CSP) at 670 kg ha⁻¹, phosphoric acid (PA) at 126 L ha⁻¹ and monoammonium phosphate (MAP) at 334 kg ha⁻¹) combined with biofertilizers (i.e., inoculation with phosphorin or mycorrhiza) on plant growth aspects, antioxidants enzyme activity, chemical constituents, yield and quality of broccoli leaves and heads (Brassica oleracea var. italica Plenck). The experiment was performed according to the randomized complete block design with three replications (n = 3), for two growing seasons (2018–2019) at the experimental farm of Benha University, Egypt. The obtained results showed that the highest values of plant height, leaf area, fresh and dry weight of leaves/plant, head weight and diameter, and the highest yield of heads ha⁻¹ were recorded in plants that received MAP fertilizer and were inoculated with mycorrhiza. On the other hand, the highest value of head length, total carbohydrate and total soluble solids (TSS) content were observed in plants fertilized with PA and inoculated with mycorrhiza. The highest leaf nitrogen % and head ascorbic acid content, as well as the lowest head total phenol content were recorded in plants supplemented with MAP fertilizer and inoculated with mycorrhiza. Moreover, broccoli plants fertilized with PA and inoculated with mycorrhiza showed promising results in terms of phosphorus, potassium and total carbohydrate content, antioxidant activity and dehydrogenase activity. In conclusion, phosphorus may affect plant growth, yield and chemical parameters in broccoli plants depending on the fertilizer source, while inoculation with mycorrhiza may also have a beneficial impact on these parameters.

Despite its value as a culinary, medicinal, and essential oil crop, caraway struggles to grow and develop its biochemical quality in drought-prone sandy soils. To tackle this challenge, we conducted two field trials under drip irrigation, testing four rates of organic manure (0, 5, 10, and 15 ton/hectare (ha) and three foliar biostimulants: vitamin B₁ (50 and 100 mg L⁻¹), vitamin E (50 and 100 mg L⁻¹), and active yeast (100 and 150 mL L⁻¹). We used a randomized split-plot design with three replicates, assigning manure rates to main plots and biostimulants to subplots. We measured plant height, stem diameter, branch number, dry biomass, umbels per plant, 1000-seed weight, seed yield (per plant and per ha), essential oil content, chlorophyll a and b, carotenoids, and leaf N, P, and K. All treatments outperformed the unfertilized control. Applying 15 ton/ha of manure alone increased mean plant height by 185.3 cm, stem diameter by 2.93 mm, branch number by 14.5, and herbal weight by 91.97 g across both seasons—a gain of about 11–15%. Foliar application of vitamin B₁ at 100 mg L⁻¹ (without manure) achieved even larger gains: mean plant height improved by 176.5 cm, stem diameter by 2.6 mm, branches number by 15.1, and herbal biomass by 103.95 g (20–36% growth increases). It also boosted essential oil yield by 1.89 mL per plant (16–50%) and enhanced nutrient uptake. The most pronounced synergy emerged when combining 15 ton/ha of manure with 100 mg L⁻¹ vitamin B₁, raising seed yield to 1698.8 kg/ha (35%), plant height to 184.7 cm (52%), number of branches to 17.4 per plant (56%), umbels to 38.1 per plant (42%), 1000-seed weight to 16.9 g (48%), and essential oil yield to 2.3 mL per plant (115%), compared to the control. Chlorophyll a increased by 50%, chlorophyll b by 33%, carotenoids by 35%, and leaf N, P, and K by 43%, 90%, and 76%, respectively. Manure combined with vitamin E or yeast delivered moderate improvements. These findings demonstrate that integrating organic manure with targeted foliar biostimulants—especially vitamin B₁—under drip irrigation, is a sustainable strategy to maximize caraway yield, oil content, and nutritional quality on marginal sandy soils.

Chia (Salvia hispanica L.) is a specialty crop capable of providing healthy food and metabolites. The goal of our study was to explore the possibility of expanding seed yield, oil production, and metabolites of chia in response to amino acid, barthenosteriode, and algae extract treatments used as bio-stimulants. The experiment was conducted in the field in a randomized complete block design with three repeats. The treatments were (1) control (spray only with water), (2) amino acids with nutrients (2 mL/L vs. 4 mL/L), (3) brassinolide (5 mL/L vs. 10 mL/L), and algae extract (2 mL/L vs. 4 mL/L). The growth and yield measurements of chia, such as chlorophyll, carotenoids, amino acids, indoles, phenols, macro- and micronutrients, carbohydrates, total oil, and fatty acids were analyzed. The chia plants sprayed with growth stimulant materials showed increases in most studied characteristics, particularly algae extract at 4 mL/L, followed by algae extract at 2 mL/L during the first and second seasons. Meanwhile, amino acids at 4 mL/L led to the third-highest increases in most cases. Conversely, all bio-stimulant treatments decreased total phenols in leaves (mg/100 g f.w.), especially seaweed at 4 mL/L, compared to high levels in the control during both seasons. Control plants showed the lowest levels of the measurements mentioned previously when scored by barthenosteriode at 5 mL/L during the first and second seasons. GLC for fixed oil in chia showed the recognition of four biocomponents. i.e., oleic, linoleic, palmitic, and α-α linolenic acids. The main biocomponent was α-α linolenic acid and reach (49.7 to 57.9%). The application of seaweed at 4 mL/L could be exploited to improve growth, seed crop, fixed oil production, chemicals and bio-constituents, especially the fixed oil composition of chia (Salvia hispanica L.) plant.