Foliar Spray Research Articles

Effects of Organic Manures and Foliar Sprays on Growth and Yield of Finger Millet

Experiments were conducted at the Centre of Excellence in Millets, Athiyandal, Thiruvannamalai, India to evaluate various organic nutrient sources with foliar application over three seasons from kharif 2015 to 2017 in Split Plot Design (SPD). Applying farmyard manure (FYM) @ 12.5 t ha-1 along with in-situ incorporation of sunhemp green manuring SGM @ 6.50 t ha-1 at 45 days after planting (DAP) resulted in higher grain and straw yields of 2,420 kg ha-1 and 3,549 kg ha-1, respectively. A foliar spray of Panchakavya at a 3% concentration increased grain and straw yields to 2,423 kg ha-1 and 3,338 kg ha-1. The B4 treatment yielded the highest gross income (₹84,724 ha-1), net income (₹55,372 ha-1), and benefit-cost ratio (2.84). Vermicompost application at 5 t ha-1 led to lower gross income. Among the foliar sprays, Panchakavya at 3% produced the highest gross income (₹84,478 ha-1), net income (₹43,534 ha-1), and benefit-cost ratio (2.36), followed by vermiwash at 3%.

Metabolic pathways regulated by strigolactones foliar spraying enhance osmoregulation and antioxidant defense in drought-prone soybean

BackgroundDrought stress is a significant abiotic stressor that hinders growth, development, and crop yield in soybeans. Strigolactones (SLs) positively regulate plant resistance to drought stress. However, the impact of foliar application of SLs having different concentrations on soybean growth and metabolic pathways related to osmoregulation remains unknown. Therefore, to clarify the impact of SLs on soybean root growth and cellular osmoregulation under drought stress, we initially identified optimal concentrations and assessed key leaf and root indices. Furthermore, we conducted transcriptomic and metabolic analyses to identify differential metabolites and up-regulated genes.ResultsThe results demonstrated that drought stress had a significant impact on soybean biomass, root length, root surface area, water content and photosynthetic parameters. However, when SLs were applied through foliar application at appropriate concentrations, the accumulation of ABA and soluble protein increased, which enhanced drought tolerance of soybean seedlings by regulating osmotic balance, protecting membrane integrity, photosynthesis and activating ROS scavenging system. This also led to an increase in soybean root length, lateral root number and root surface area. Furthermore, the effects of different concentrations of SLs on soybean leaves and roots were found to be time-sensitive. However, the application of 0.5 µM SLs had the greatest beneficial impact on soybean growth and root morphogenesis under drought stress. A total of 368 differential metabolites were screened in drought and drought plus SLs treatments. The up-regulated genes were mainly involved in nitrogen compound utilization, and the down-regulated metabolic pathways were mainly involved in maintaining cellular osmoregulation and antioxidant defenses.ConclusionsSLs enhance osmoregulation in soybean plants under drought stress by regulating key metabolic pathways including Arachidonic acid metabolism, Glycerophospholipid metabolism, Linoleic acid metabolism, and Flavone and flavonol biosynthesis. This study contributes to the theoretical understanding of improving soybean adaptability and survival in response to drought stress.

The effect of foliar spraying of some micronutrients and lanthanum on the morphological and physiological characteristics of summer savory (Satureja hortensis L.) under hydroponic and soil conditions

BackgroundThe use of lanthanum (La) as a rare element has increased in agriculture. Summer savory (Satureja hortensis L.) is an herbaceous and medicinal plant that has received attention recently. The present study aimed to investigate the effects of foliar application of zinc (Zn), copper (Cu), manganese (Mn), and La at different growth stages, including vegetative, reproductive, and vegetative to harvest on morphological and physiological traits of S. hortensis under hydroponic and soil conditions in the greenhouse. The study was arranged in a factorial experiment based on a completely randomized design (CRD) with three replications.ResultsResults of hydroponic condition showed that foliar application of Cu, Zn, and Mn were the most effective treatments to improve the measured morphological and physiological traits. Moreover, La was not more appropriate in increasing the quantitative and qualitative characteristics. Also, results showed that in soil cultivation, foliar application of micronutrient elements increased the ratio of leaf-to-stems, antioxidant compounds, and the percentage of essential oils, while the application of Mn, Cu, Zn, and La did not have positive effects on the increase in vegetative characteristics in all three stages of foliar application compared with the control treatment.ConclusionsCu, Zn, and Mn in appropriate concentrations can increase growth and physiological characteristics of summer savory in hydroponic systems.

The Application of a Foliar Spray Containing Methylobacterium symbioticum Had a Limited Effect on Crop Yield and Nitrogen Recovery in Field and Pot-Grown Maize.

In this study, the effectiveness of an inoculant containing a nitrogen (N)-fixing microorganism (Methylobacterium symbioticum) was evaluated on maize (Zea mays L.) grown both in the field (silage maize) and in pots over two years (2021 and 2022). The field trial included the following two treatments: with (Yes) and without (No) the inoculant. The pot experiment was designed as a factorial arrangement with two factors: the application of the inoculant (Yes and No) and N applied to the soil (0, 0.4, 0.8, and 1.6 g pot-1). In the field, total dry matter yield (DMY) did not differ significantly between treatments, although the average DMY was higher in the inoculant treatment. In pots, the total DMY varied significantly across all N rates but was only significantly affected by the inoculant application in 2022. N fixation estimates in the field were 58.8 and 14.5 kg ha-1 for 2021 and 2022, respectively, representing 23.7% and 9.1% of the N recovered in the aboveground plant parts. In pots, the estimated fixed N values were -49.2 and 199.2 mg pot-1 in 2021 and 2022, respectively, which corresponded to -5.2% and 18.5% of the N found in the aboveground plant parts. Considering the average values obtained across the four cultivation conditions, there was a positive outcome for the treated plants. However, these values cannot be considered significant when compared to nitrogen removal in maize crops. A commercial product should provide an unequivocal and quantitatively relevant contribution to plant nutrition, which did not appear to be the case. Thus, for this inoculant to provide reliable guarantees of positive outcomes for farmers and become a useful tool in promoting more sustainable agriculture, further studies appear necessary. These studies should aim to determine in which crops and under what cultivation conditions the application of the inoculant is truly effective in enhancing N fixation and improving crop productivity.

Phytotoxicity Stress Induced by Allelochemicals from Foliar Spray of Sida cordifolia Methanol Leaf Extract on Ageratum conyzoides and Oryza sativa

Allelochemicals are key inhibitors that induce chemical stress in plants. Their mechanisms as agents of oxidative stress are not well understood. A field study was conducted to evaluate herbicidal potential of Sida cordifolia methanol leaf extract (SCLE) on Ageratum conyzoides and Oryza sativa (weedy rice). SCLE concentrations of 0, 3, 6 and 9 g L-1 were prepared and sprayed twice at 7 days interval. The results showed that the SCLE significantly (p<0.05) affected growth attributes, chlorophyll pigments, and proline, and catalase, superoxide dismutase and peroxidase enzyme activities in a concentration-dependent pattern. It was found that high concentrations of SCLE induced greater phytotoxicity against A. conyzoides compared to O. sativa. SCLE spraying stimulated production of reactive oxygen species, boosting their ability to cause damage and inhibit growth. The allelochemicals in the extract stimulated an increased in the level of proline, which is an indicator of oxidative stress. Understanding the physiological and biochemical responses to Sida extract can improve our knowledge on allelochemical target sites and help us to explicate the mechanisms of action of such compounds.

Conventional and Nano-Zinc Foliar Spray Strategies to Improve the Physico-Chemical Properties and Nutritional and Antioxidant Compounds of Timor Mango Fruits under Abiotic Stress

Zinc deficiency is common under heat stress, and further research is needed to determine how to enhance the fruit quality of mango trees through the use of three forms of zinc, namely Zn-NPs, zinc sulfate (ZnSO4), and chelated zinc (Zn-chelated), as a foliar spray. This research was carried out using ten treatments to investigate the effect of zinc forms on the fruit quality of Timor mango trees. With a few notable exceptions, every fruit quality measurement (physical characteristics, chemical properties, mineral contents, and antioxidant compounds) responded to every treatment looked into; however, the extent of the reaction differed depending on the fruiting measurement. Furthermore, the Zn-NPs created a larger difference in the fruiting measurements than the ZnSO4 and Zn-chelated forms. ZnO NPs at 100 ppm ranked first, followed by ZnO NPs in the first spray and zinc EDTA in the second spray, followed by ZnO NPs in the first spray and ZnSO4 in the second, for all mineral content and antioxidant compound measurements and most of the fruit physico-chemical characteristics. In contrast, the lowest levels of minerals and antioxidant compounds and most of the fruit physico-chemical characteristics were found in the controls. The outcomes of the other treatments after the three treatments lay somewhere between these two extremes, and this pattern was detected throughout two seasons. Spraying Timor mango trees with nano, chelated, and sulfate zinc can be considered a safe and environmentally friendly natural method for improving fruit quality in abiotic stress regions.

Foliar application of esculin and digitoxin improve the yield quality of salt-stressed flax by improving the antioxidant defense system

BackgroundSecondary metabolites of several plants, including esculin and digitoxin, which are cardiac glycosides, were previously employed for their therapeutic effects. The current study aims to investigate the functions of the main Na+ /K+ transport inhibitor digitoxin and the antioxidant esculin for enhancing flax plant growth and production under salinity.MethodologyFlax plants were irrigated with distilled water supplemented with 0.0 and 5000 mg/L salt solution starting from 15 DAS from sowing. Then exogenous treatment with digitoxin and esculin with 50 mg L− 1 and 100 mg L− 1 were used for this work.ResultsAccording to the results of this work, foliar spraying of esculin or digitoxin increased the salinity tolerance of flax plants.The foliar application of either esculin or digitoxin induced an elevation in the contents of photosynthetic pigments, osmolytes including soluble sugar and proline as well as the total phenols in salt-stressed flax plants. Moreover, esculin and digitoxin in particular counteract oxidative stress by increasing the activity of antioxidant enzymes including superoxide dismutase, catalase, peroxidase, phenylalanine ammonia-lyase, and tyrosine ammonia lyase, leading to a decrease in reactive oxygen species and lipid peroxidation levels and electrolyte leakage. The efficiency of esculin and digitoxin to sustain ion homeostasis by inhibiting Na+ absorption and increasing potassium, calcium, and phosphorus in flax plants may be the reason for their protective actions towards salinity.As a consequence, esculin and digitoxin increased yield quantity and quality as shown by increases in all investigated yield criteriaas shoot height, root length, their fresh and dry weights as well asseed yield/plant (g), and 1000 seeds weight, especially those that improved the desired oil properties.ConclusionIn conclusion, this study concluded that digitoxin was more effective in inhibiting Na+ build-up and increasing flax salinity tolerance, particularly at the high investigated dose as compared to esculin. In this study, we reported the recent findings of exogenousapplication of either digitoxin or esculin glycosides which are new investigated salt alleviators never used before for improving the salt tolerance in flax plants.

Effects of foliar spraying with melatonin and chitosan Nano-encapsulated melatonin on tomato (Lycopersicon esculentum L. cv. Falcato) plants under salinity stress

Melatonin has been found to be crucial in the growth and development of plants under stress conditions. In this study, the effects of melatonin and nano melatonin regarding the growth and development of tomato plants, along with their photosynthetic pigment, phenol, and antioxidant activity, were investigated under saline conditions. The study was conducted using a completely randomized design with three replications, and the applied treatments were salt stress and foliar spraying of melatonin at a concentration of 0 (control), melatonin (Mel), and nano capsule-melatonin (Nano-Mel) at 500 µM. Salinity treatments included application of sodium chloride with two concentration of 0 mM NaCl (S1) and 50 mM NaCl (S2). Under saline conditions, Mel and Nano-Mel increased both shoot and root fresh and dry weights, improved relative water content (RWC), and enhanced antioxidant activity and phenolic content. Salinity elevated leaf ABA content, unaffected by Mel or Nano-Mel. Chlorophyll fluorescence and SPAD values demonstrated resilience to salinity with Mel and Nano-Mel applications. Nano-Mel notably mitigated Na + accumulation in leaves under salinity, helping maintain K + homeostasis. Proline levels rise due to salinity but decreased with Mel and Nano-Mel treatments. Electrolyte leakage (EL) increased under salinity but is significantly reduced by Mel, indicating enhanced membrane stability. The findings reveal that salinity stress significantly reduced plasma membrane intrinsic protein (PIP) expression in roots and leaves, whereas Mel and Nano-Mel treatments enhance PIP expression, particularly in roots. The study concludes that Mel and Nano-Mel effectively alleviate salinity-induced stress, promoting growth and maintaining physiological homeostasis in tomato plants.

Investigating the Role of Viruses in the Rapid Decline of Young Apple Trees in High-Density Orchards in New York

A sudden, unexplained decline and collapse of young apple trees on dwarfing and semi-dwarfing rootstocks has been reported across North America over the past decade. Although viruses have been detected in declining trees, no information is available on their potential causal role in the decline phenomenon. To this end, virus-inoculated apple trees were established in a high-density experimental orchard and monitored over five years. Tree decline was observed in year 4 (2022), resulting in 17% mortality, with declining trees exhibiting marked vascular tissue necrosis. However, none of the eight viruses and one viroid detected in the experimental orchard was significantly more prevalent in declining trees. Extreme temperature fluctuations in January 2022, followed by a severe water deficit in summer 2022, were recorded at the experimental orchard. Similar but distinct observations were made in a nearby commercial orchard with foliar nutrient imbalances documented in trees exhibiting symptoms of rapid decline. Together, our findings suggest that viruses are not primarily responsible for the rapid decline phenomenon and highlight the need for future work to investigate the roles of tree physiology and water stress in tree decline, as well as the potential efficacy of horticultural mitigation practices.

Effect of different levels of micronutrients on vegetative growth, yield and fruit quality of Mango (Mangifera indica L.)

An experiment was carried out to ascertain the impact of foliar application of certain micro-nutrients on fruit yield and quality of Mango (Mangifera indica L.) cultivars "Dashehari" and "Langra" at Agriculture Research Station, Banswara, Maharana Pratap University of Agriculture and Technology, Udaipur, Rajasthan, during the year 2016-17 on seventeen years old mango trees. The experiment was laid out in One way ANOVA (Randomized Block Design) with eight treatments in thrice replications for combinations with different micronutrients Zinc sulphate, Copper sulphate, Borax, boric acid and IIHR-2 mango special were applied on mango cultivars "Dashehari" and "Langra" at different growth stages. All were fertilized with a recommended dose of NPK (1500:500:1000 g as N, P2O5 and K2O). The spraying was done twice; during mid-October, mid-December, and mid-February before the flowering stage and again in mid-March at the marble stage during both years of study. Foliar sprays, in general, improved fruit yield. Yields were exceptionally higher in response to foliar application of Zinc (Zn), Copper (Cu) and boron (B) compared to other treatments. Result proved that foliar application of mango trees with [(RDF + Zinc sulphate (100 g) + Copper sulphate (50 g) + Boric acid (50 g) as soil + Zinc sulphate (0.2%) + Copper sulphate (0.1%) + Boric acid (0.1%) as foliar (Two sprays before flowering and marble stage)] was the promising treatment for improvement of vegetative growth, yield and fruit quality. This treatment was also found best for maximum total carotenoids, average fruit weight as well as fruit yield.

Short‐Term Benefits of Tillage and Agronomic Biofortification for Soybean–Wheat Cropping in Central India

ABSTRACTIn a changing climate, conservation tillage and agronomic biofortification are essential for enhancing crop yield, nutritional security, carbon stocks, and soil quality. Consequently, a field study was conducted in central India to assess the short‐term (4 years) effects of crop establishment techniques (CETs) and agronomic biofortification methods (ABMs) on soil health indicators, grain yield, and quality in the soybean–wheat cropping system. The experiment followed a split‐plot design with two CETs in the main plots (permanent broad bed furrow, PBBF, and conventional tillage, CT) and eight ABMs, each with three replications. The results indicated that PBBF and ABMs (seed inoculation with the microbial strains MDSR 14 + MDSR 34, and soil and foliar application of Zn+Fe) improved soil carbon stock (by 49.6% and 52.4%), available nitrogen, phosphorus, potassium, available Zn (by 30.0%), and Fe (by 21.9%) after the fourth year of the study. Similarly, PBBF and microbial inoculation increased soil enzyme activities (dehydrogenase, acid phosphatase, and β‐glucosidase), substrate‐induced respiration, and microbial biomass carbon content. As a result, a higher soybean equivalent yield (5.59% higher in PBBF and 14.2% higher with foliar spray of Zn+Fe) and seed quality attributes (crude protein yield, grain Zn, and Fe) were observed in PBBF and the foliar spray of Zn and Fe treatments compared to CT and control, respectively. Overall, adopting the short‐term PBBF system, microbial inoculation, and soil and foliar application of Zn and Fe improved rhizosphere biochemical properties, yield, and seed quality in the soybean–wheat system.

Evaluation of transplant drench and foliar insecticide applications for wireworm (Coleoptera: Elateridae) management in sweetpotato.

The revocation of chlorpyrifos tolerances in 2022 left sweetpotato growers without their most important tool to combat a complex of soil-borne root pests that includes wireworms (Coleoptera: Elateridae). Since then, growers have reported increased root damage despite a rapid pivot to pyrethroid-based management systems to replace mechanically incorporated preplant chlorpyrifos broadcast sprays. Our goal was to evaluate the efficacy of alternative insecticide chemistries and application methods to expand the portfolio of management options for wireworms, specifically Conoderus spp. and Melanotus communis (Gyllenhal). We tested (i) insecticidal transplant water drenches and (ii) a foliar spray program targeting adult elaterids. We found that incorporating insecticides into transplant water reduced wireworm damage when compared to untreated transplant water. Our treatments included a recently registered meta-diamide, broflanilide, which represents a promising path to diversify active ingredients and shift away from an overreliance on preplant and post-directed pyrethroid soil sprays. Foliar spray plots had less damage than plots that did not receive foliar sprays. One benefit of adult-focused management is the availability of effective monitoring tools such as sex pheromones and blacklight trapping. Developing a robust adult monitoring program would enable more precise applications of foliar insecticides versus season-long prophylactic soil sprays targeting larvae. Our results demonstrated a significant benefit to both alternative delivery methods. These management alternatives could expand treatment options beyond traditional preplant and post-directed pyrethroid sprays.

The role of the application of nanosilver and humic acid on the physiological and yield traits of corn (Zea Mays L.) under deficit irrigation conditions

Water deficit is the most common abiotic stress and at least 75% of corn fields in Iran are exposed to drought stress during different stages of growth. humic acid (HA) and nanosilver (NS) can help mitigate abiotic stresses in plants; especially drought stress. A field experiment was conducted to study the effect of humic acid and nanosilver on the physiological traits and yield of corn during two crop years. Experimental treatments were including deficit irrigation (100%, 80%, 60% of crop water requirement (CWR)) and nanosilver (0 (NS0), 60 (NS60), 80 (NS80) and 100 (NS100) microliters/liter/ha) and humic acid (control (HA0), 500 (HA500) and 1000 (HA1000) g/ha). The highest amount of chlorophyll a, b and total in 100% CWR+NS60+HA1000 was obtained. The highest amount of proline in 60% CWR + NS60 +HA1000 as well as treatment NS0 +HA1000 were observed. In all irrigation levels, the application of NS100 has reduced chlorophyll a and total. The yield components were affected by HA and nanosilver foliar spraying. The highest grain yield was observed in 100% CWR with the application of NS60 +HA500 at the rate of 10,582 kg/ha. In conditions of 100% CWR, nanosilver concentrations had a positive effect on plant growth and yield, and with increasing stress, high concentrations of nanosilver had a negative effect on growth and yield, but with the combined application of nanosilver and HA, the effect of drought stress decreased, which indicates the positive effect of HA in improving plant growth and yield.

Nanoparticles supplementation through foliar feed contributed to the growth and cocoon yield of silkworm (Bombyx mori)

An experiment was conducted during 2021–22 and 2022–23 at University of Agricultural Sciences, Dharwad, Karnataka to study the effect of metal nanoparticles on silkworm (Bombyx mori) growth and cocoon yield. The experiment was laid out in completely randomized design (CRD) comprised of 11 treatments with 3 replications. The various concentrations (50, 100 and 200 ppm) of nanoparticles, viz. nano silver, nano zinc and nano copper were extrafoliated to mulberry leaves and were administered to silkworms daily once at morning (first feed) from second day of fifth instar. The study revealed that, silver nanoparticles at 200 ppm concentration emerged as the best supplement with improved larval, cocoon and silk parameters by recording shorter larval duration (616.42 h), fifth instar duration (166.12 h), higher mature larval weight (40.626 g/10 larvae), effective rate of rearing (97.58%), silk productivity (6.225 cg/day), silk gland weight (1.885 g/larva), pupal weight (13.757 g/10 pupae), cocoon yield (794.85 g/dfl), cocoon weight (18.102 g/10 cocoons), shell weight (4.307 g/10 shells), cocoon shell ratio (23.79%), cocoon filament length (948.52 m), finer denier (2.75 d), highest fibroin (80.23%) and lowest sericin protein (19.78%).

Impact of green carbon dot nanoparticles on seedling emergence, crop growth and seed yield in blackgram (Vigna mungo L. Hepper)

Carbon Dots (CDs) were synthesized from peanut shells (PNS) through pyrolysis and characterized using FTIR, XRD, HRTEM and BET analysis revealing an average size of 2–5 nm with amorphous nature. Synthesized PNS-CDs was employed both as priming and foliar agent for enhancing seed quality and crop productivity in blackgram (Vigna mungo L. Hepper). Different concentrations ranging from 50, 100, 200, 300, 400, 500 and 1000 ppm was used for seed priming and 5, 10, 15, 20, 25, 50, 75 and 100 ppm were given as foliar spray on 30th and 45th days after sowing (DAS). On accounting the best seed priming and foliar spray concentrations, field trial was conducted to validate the optimistic effect of PNS-CDs on blackgram crop productivity. Results revealed that priming with 200 ppm for 3 h exhibited maximum seed imbibition (54%), germination (88%) and vigour index (3165). Whereas, foliar spray with 50 ppm expressed significant improvement in leaf area index (2.6), total chlorophyll (2.70 mg/g), total soluble protein (71 mg/g), Number of nodules/plant (138), seed yield/plant (8.7 g) and 100 seed weight (5 g). The impact of PNS-CDs treatments resulted in increased photosynthetic rate (12.45 µmol CO2 m−2s−1), transpiration rate (3.13 mmol H2O/m−2s−1), stomatal conductance (0.55 mol H2O/m−2s−1) and internal leaf CO2 concentration (652 µmol CO2 m−2s−1) which ultimately enhanced the photosynthetic efficiency of plants. It has also exhibited a promising effect on the resultant seed in which the combination seed priming (200 ppm) followed by foliar spray (50 ppm) recorded maximum 100 seed weight (4.19 g), germination (97%) and vigour index (3019). Thus, this study highlights the promising role of PNS-CDs as a sustainable and effective agricultural nanomaterial, offering a novel approach to utilize the agricultural waste and also to enhance the crop productivity through advanced non-chemical approach.

Effect of Different Plant Growth Regulators Applied as Foliar Sprays on the Growth and Flowering of Brinjal (Solanum melongena L.) under Agro-Climatic Conditions of Chhattisgarh Plains, India

Present investigation “Effect of different plant growth regulators applied as foliar sprays on the growth and flowering of Brinjal (Solanum melongena L.) under agro-climatic conditions of Chhattisgarh plains” in var. Kashi Taru is located at the farm of KVK (Raipur) affiliated with IGKV, Raipur,(C.G.) in Rabi season 2022-23.The experiment was conducted in RBD (Randomized Block Design) with 3 replications, consisting of 10 treatments of 3 plant growth regulators with different concentrations, including GA3 (25, 50 and 75 ppm); IAA (25, 50 and 75 ppm) and NAA (25, 50 and 75 ppm) along with control as foliar application at pre flowering stage (30 DAT) and pre fruiting stage (45 DAT). Among the different treatments, the findings indicated that the application of Treatment T3 i.e. GA3 @ 75 ppm gave the maximum plant height (89.96 cm), primary branches (11.76) and secondary branches (25.17) per plant over control. The least days taken to 50% flowering were recorded (51.62 days) with GA3@ 75 ppm and maximum days taken to 50% flowering were found with control (58.87 days). The highest number of flowers per cluster was recorded in GA3@ 75 ppm (4.01), followed by NAA@75 ppm (3.97). Thus, a suitable level i.e., 75 ppm of GA3, is effective in enhancing brinjal growth and flowering in the agro-climatic conditions of the Chhattisgarh plains.

Mathematical approach used for the assessment of foliar application of biostimulant and fertilizers to coriander varieties (Coriandrum sativum L.)

The biostimulants and fertilizers applied as foliar spray or directly to soil play a crucial role in enhancing the development and quality of coriander by supplying essential macro- and micro-nutrients. The ecological approach to reducing soil fertilizers prioritizes the utilization of foliar nutrients. The objective of this study was to investigate the impact of foliar applying products on the seed yield, essential oil content and composition of coriander cultivars in Central Bulgaria. The field trial was carried out on alluvial-meadow soil type in the region of Plovdiv, Central Bulgaria, in the period 2020–2022. The experiment was conducted using the approach of fractional parcels with four repetitions. Three foliar products were examined in the relevant rates: Energy 20–8–60 – 25 L ha−1; Fulvin 40–22 – 80 L ha−1; Isabion – 30 L ha−1. The treated plants were compared to an untreated control. The tested products were applied in the end of the budding stage to five coriander varieties: Yantar, Moroccan, Mesten Drebnoploden, Thüringen and Marino. Results showed that the application of foliar products, compared to the control, led to an increase in seed yield by 4.2–9.6 % and essential oil content up to 11.8 %. Statistical analysis has demonstrated that the utilization of the Energy 20–8–60 has the most significant impact on the concentration of essential oils, while Isabion has the biggest influence on the quantity of seeds produced. The Isabion biostimulant increased the content of the main compound – β-linalool in the essential oil of Moroccan variety up to 8.9 % and Marino and Mesten Drebnoploden by 3.6 and 5.4 % respectively, compared to the control. The foliar application of Energy 20–8–60 fertilizer led to a decrease of β-linalool percentage in Marino, Moroccan, Mesten Drebnoploden and Thüringen. All studied varieties exhibited the presence of aldehyde 2E-tridecen-1-al under the impact of foliar fertilizers, whereas the untreated plants did not.

Hydrogel Embedding Enables Enhanced Leaf Deposition and Bioavailability of Fe-Based Engineered Nanoparticles.

Nanofertilizers comprising engineered nanoparticles (ENPs) have great potential in sustainable agriculture due to their strong capabilities of improving crop yields. As an effective fertilization strategy, foliar spraying could lead to broken and splashed ENP droplets, resulting in inaccurate leaf targeting and potential environmental contamination. Herein, we propose embedding Fe-based ENPs into a supramolecular hydrogel to effectively enhance the deposition amount on leaves and thus the bioavailability. The proper rheological properties of the hydrogel droplets and their robust interaction with soybean leaf simultaneously reduce the droplet rebound and fragmentation, especially under elevated impact speeds, resulting in up to 168.9% more droplet deposition compared to the ENP suspension. Computational fluid dynamics simulation analysis suggests that the contact angle is a key sensitive factor influencing the dynamic deposition behavior of the hydrogel droplet. A 15% reduction in the contact angle results in a 14% reduction of the highest bouncing height. The incorporation of ENPs enhances the viscous dissipation rate by 7.4% in comparison with pure hydrogel droplets. The hydrogel embedding also causes a 1.5-fold increase in ENP uptake compared to that of the ENP suspension. The hydrogel embedding delivers a reduction of 80% in the ENP application amount, compared to ENP suspensions, while achieving a 28% increase in the fresh weight of soybean seedlings. This work provides an effective method to enhance the deposition of ENPs during foliar application.

RESPONSE OF TWO MUSKMELON HYBRID TO SEAWEED AND LICORICE ROOT EXTRACT FOLIAR FERTILIZERS

A field experiment was conducted at Malta Dohuk government research farm in Dohuk province to investigate the impact of licorice root extract at three concentrations (0, 8, and 16 g.L-1) and Maxi Grow at three concentrations (0, 5, and 10 ml.L-1) on two muskmelon hybrids (ES 3111 F1 and ES 335 F1). Both hybrids received foliar sprays, and their combined effects on the growth and yield of the hybrids were examined. The experiment adhered to a randomized complete block design (RCBD) with three replicates. The results demonstrated that the influence of the muskmelon hybrids on growth and yield was not significant, except for Total Soluble Solids (TSS), which was higher in the hybrid ES 3111 F1 compared to ES 335 F1. In contrast, Maxi Grow at (10) ml.L-1 exhibited significant positive effects on all studied traits compared to the control group. Similarly, foliar application of licorice root extract at 16 g.L-1 significantly enhanced vegetative growth parameters (number of leaves per plant, number of branches per plant, with no effect on chlorophyll content), as well as stem diameter and yield-related traits such as the number and weight of fruits per plant. Notably, the combined interaction of licorice root extract at 16 g.L-1 and Maxi Grow at 10 ml.L-1 had the most favorable impact on the studied characters, particularly when applied to the ES 335 F1 hybrid. The results suggest that the use of licorice root extract and Maxi Grow is recommended for the organic production of the ES 335 F1 hybrid.

Green synthesized iron oxide nanoparticles as a potential regulator of callus growth, plant physiology, antioxidative and microbial contamination in Oryza sativa L.

In tissue culture, efficient nutrient availability and effective control of callus contamination are crucial for successful plantlet regeneration. This study was aimed to enhance callogenesis, callus regeneration, control callus contamination, and substitute iron (Fe) source with FeO-NPs in Murashige and Skoog (MS) media. Nanogreen iron oxide (FeO-NPs) were synthesized and well characterized with sizes ranging from 2 to 7.5 nm. FeO-NPs as a supplement in MS media at 15 ppm, significantly controlled callus contamination by (80%). Results indicated that FeCl3-based FeO-NPs induced fast callus induction (72%) and regeneration (43%), in contrast FeSO4-based FeO-NPs resulted in increased callus weight (516%), diameter (300%), number of shoots (200%), and roots (114%). Modified media with FeO-NPs as the Fe source induced fast callogenesis and regeneration compared to normal MS media. FeO-NPs, when applied foliar spray, increased Plant fresh biomass by 133% and spike weight by 350%. Plant height increased by 54% and 33%, the number of spikes by 50% and 265%, and Chlorophyll content by 51% and 34% in IRRI-6 and Kissan Basmati, respectively. Additionally, APX (Ascorbate peroxidase), SOD (Superoxide dismutase), POD (peroxidase), and CAT (catalase) increased in IRRI-6 by 27%, 29%, 283%, 62%, while in Kissan Basmati, APX increased by 70%, SOD decreased by 28%, and POD and CAT increased by 89% and 98%, respectively. Finally, FeO-NPs effectively substituted Fe source in MS media, shorten the plant life cycle, and increase chlorophyll content as well as APX, SOD, POD, and CAT activities. This protocol is applicable for tissue culture in other cereal crops as well.