Humic Acid Application Research Articles

Impact of a Single Lignite Humic Acid Application on Soil Properties and Microbial Dynamics in Aeolian Sandy Soils: A Fourth-Year Study in Semi-Arid Inner Mongolia

Impact of a Single Lignite Humic Acid Application on Soil Properties and Microbial Dynamics in Aeolian Sandy Soils: A Fourth-Year Study in Semi-Arid Inner Mongolia

Pengaruh Pembenah Tanah Cair dan Pupuk N, P, K terhadap Pertumbuhan Serta Hasil Tanaman Bawang Merah (Allium cepa, L.)

This research aims to determine the effects of humic acid application on soil pH, organic carbon (C-Organic), cation exchange capacity (CEC), as well as the growth and yield of shallots. The study was conducted at the Ciparanje Experimental Garden, Faculty of Agriculture, Padjadjaran University, Jatinangor, Sumedang, from November 2023 to February 2024. The experimental method used was a Randomized Complete Block Design (RCBD) with six treatments and five replications. The treatments were: A; (0.5 Soil Amendment and 1 Standard N, P, K), B; (1 Soil Amendment and 1 Standard N, P, K), C; (1.5 Soil Amendment and 1 Standard N, P, K), E; Without Standard N, P, K and Soil Amendment (Control), and F; (Standard N, P, K). The results showed that the combination of soil amendments and N, P, and K fertilizers significantly affected the parameters of soil pH, C-Organic, CEC, and plant height at 14, 28, 42, and 56 days after planting (DAP); stem diameter at 14, 28, 42, and 56 DAP; number of tillers at 14, 28, 42, and 56 DAP; and shallot plant weight.

Effect of Foliar Application of Humic Acid on Vegetative Growth Attributes of Jamun (Syzygium cumini (L.) Skeels.) cv. Goma Priyanka

A field experiment was carried out at Instructional Farm, Department of Fruit Science, College of Horticulture and Forestry in Jhalarapatan, Jhalawar during 2021-22 and 2022-23 with the object of assessing the response of foliar application of humic acid on growth attributes of Jamun (Syzygium cumini (L.) Skeels) cv. Goma Priyanka. The experiment comprised of 4 treatment combinations in randomized block design with three replications consisted of HA0: [Control], HA1: [1000ppm humic acid], HA2: [2000 ppm humic acid], and HA3: [3000 ppm humic acid]. On the basis of the results emanated from present investigation, it could be concluded that foliar application of humic acid HA3 (3000 ppm) was significantly superior plant growth parameters viz. rootstock girth, scion girth, plant height, canopy volume, canopy spread E-W, N-S, of Jamun cv. Goma Priyanka plants.

Enhancing Mango Productivity with Wood Vinegar, Humic Acid, and Seaweed Extract Applications as an Environmentally Friendly Strategy

Enhancing Mango Productivity with Wood Vinegar, Humic Acid, and Seaweed Extract Applications as an Environmentally Friendly Strategy

Effects of Humic Acid from Weathered Coal on Water-Stable Aggregates and Pore Structure of a Reclaimed Cambisol

To clarify the effects of weathered coal humic acid on water-stable aggregates and pore characteristics of reclaimed cambisol, this research analyzed the evolution characteristics of soil aggregates and pores. Effects of different humic acid dosages (0, 1%, 3%, and 5% by weight) and application period (1 year, 2 years, and 3 years) on soil aggregates and organic carbon components in soil water-stable aggregates were investigated. The results showed that it is advisable to have an addition of 5% weathered coal humic acid in reclaimed cambisol. The humic acid of weathered coal promoted the disintegration and transformation of water-stable aggregates and increased soil pore p > 75 μm. At 3 years, the structure of reclaimed soil was the most stable, with more robust connected pores, and the irregular pores increased. The humic acid of weathered coal has the potential to be used as an effective organic amendment for improving the quality of reclaimed cambisol.

Effect of Humic Acid Application Methods on Nutrients Availability and Growth and Yield of Okra(ABELMOSCHUS ESCULLANTUS L.)

A field experiment was conducted at the Agricultural Research Station, College of Agriculture, University of Basrah during the growing season of 2021- 2022 to study the effect of adding humic acids either to soil or spraying on plant along with recommended chemical fertilizers(NPK) on availability of N, P, and K and EC and pH of soil as well as growth and yield of okra. The results showed an increase in the availability of N,P and K by adding humic acid to the soil while spraying of humic acid had no clear differences with chemical fertilizers treatments. Addition of humic acid to soil decreased EC while addition as foliar application increase EC of soil. Addition of humic acid along with chemical fertilizers to soil or spraying on plant led to an increase in concentrations of N, P, and K in the leaves and their uptake with superiority of spraying treatment over soil application treatments. Increasing humic acid level spraying on plant from 0.5 to 1.0gL-1 significantly decreased N,P and K concentrations and uptakes. Similar findings were obtained for dry matter and fruits yield. The lower the level of humic acid ,The higher the dry matter and yield. The highest value of okra fruit yield 2791.06 kgha-1 was obtained with treatment involved spraying of 0.5gL-1 humic acid plus full recommended chemical fertilizers.

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.

Impacts of Humic Acid on Growth and Yield of Wheat: A Review

Wheat (Triticum aestivum L.) is a crucial crop, providing 20% of caloric intake for many populations worldwide. Soil organic matter, an essential component of soil, directly influences soil fertility and texture. Humic substances, derived from biomolecules' physical, chemical, and microbiological transformation, are integral to soil humus. Humic acid has become a standard method for enhancing crop growth, yield, and soil fertility. While the effects of humic acid on wheat have been extensively studied, the optimal type and application method for wheat cultivation remain undetermined. This review investigates sustainable wheat production methods using humic acid to mitigate the negative impacts of chemical fertilizers and climate change factors. Research indicates that humic acid significantly increases wheat plant growth parameters: shoot length (18%), root length (29%), shoot dry weight (76%), root dry weight (100%), and chlorophyll content (96%). Moreover, humic acid substantially improves wheat yield and yield components, including spike length (14.66%), number of spikes per square meter (28.73%), number of spikelets per spike (23.52%), and 1000-grain weight (23.90%). As a sustainable organic substance, humic acid application offers a promising approach to improving wheat production. This method could help meet the food demands of the growing global population, particularly in countries like Afghanistan, where food security is a pressing concern.

Effect of Humic acid and levels of Zinc and Boron on Chemical Behavior of Zinc in Calcareous Soil

There are global concerns about the significant increase in the concentrations of heavy elements due to the increase in agricultural, urban and industrial activities, which poses a threat to the natural environment and humans. This study focused on studying the addition of humic acid and different levels of zinc on the presence of zinc in the soil in its different forms and its readiness for the plant to find the best concentration and with the presence or absence of humic acid. This study was carried out on the sunflower crop, as zinc was added at levels of (0, 15 and 30) kg h-1 and humic acid at two concentrations, (0 and 50) kg h-1. Zinc was extracted successively and total and available zinc was measured. The results indicated: Concentration of total and available Zinc associated with carbonate minerals, with oxides, and with organic matter in soil increased with increasing levels of Zinc added to soil, reaching 8.638, 1.049, 1.971, 1.658 and 1.625 mg kg-1 soil, respectively. The effect of added humic acid was significant in reducing the concentrations of total Zinc, Zinc bound to carbonate minerals, bound to oxides and residues. The maximum concentrations in case of not adding acid reached 9.313, 1.8957, 1.424, and 4.300 mg kg-1 soil, respectively, while the effect was positively in increasing available concentration associated with organic matter, as concentration in case of adding humic acid reached 0.851 and 1.4584 mg kg-1 soil, respectively. In the case of adding humic acid, this study is considered good for the results it showed in increasing the available zinc with the presence of humic acid, which is reflected in the plant growth and maintaining this element within the recommended concentrations. We determined Zn speciation in the soil system and evaluated the effects of humic acid application on the basic soil properties and Zn bioavailability.

Combined applications and Multi-Faceted evaluations of humic acid, seaweed, and vermicompost with chemical and organo-mineral fertilizers on corn, part I: chlorophyll concentration

This study investigated the effects of various fertilizers on the leaf chlorophyll content of the Simpatico (FAO300) silage corn variety under field conditions. Different application combinations were tested, including treatments with and without foliar fertilizers. The foliar fertilizers used were seaweed (SW), humic acid (HA), and vermicompost (VC), combined with granular fertilizers DAP, UREA, OMB, and OMT. Granular fertilizers were applied to the soil, while foliar fertilizers were applied at four different stages: the 4-6 leaf period, 11-13 leaf period, 14-16 leaf period, and at corn tassel. Chlorophyll content in plant leaves was measured using a SPAD-502 device during these periods. The highest SPAD chlorophyll ratios were recorded with OMB-OMT (42.583) and DAP-OMT (42.150) treatments, which did not include foliar fertilizers. Conversely, the lowest SPAD chlorophyll ratio, 28.983, was observed in the DAP-UREA treatment. Treatments with foliar fertilizers resulted in an increase in SPAD chlorophyll by 11.3% to 15.7%, with the greatest improvements observed with vermicompost and humic acid, compared to treatments without foliar fertilizers. Additionally, analysis of periodic effects showed that the highest SPAD chlorophyll ratios were found during the third and second measurement periods, while the lowest ratios were observed in the first measurement period. The use of organo-mineral fertilizers and foliar applications of vermicompost and humic acid were found to enhance the leaf chlorophyll content of corn.

Process Condition Optimization and Structural Feature Analysis of Humic Acid Extraction from Weathered Lignite.

In this study, response surface methodology (RSM) was adopted to investigate the optimization of process conditions for extracting humic acid (HA) from coal, aiming to enhance the yield of humic acid. Additionally, UV-vis spectroscopy, FTIR, XRD, TG-DTG, CP/MAS13CNMR, XPS, and molecular fluorescence were utilized to examine the properties of HAs. The extraction time significantly influenced the yield from Lishi weathered lignite, while the liquid-solid ratio had a significant impact on the yield from Wuhai weathered lignite. The interactive effect between factors did not have a significant effect on the yield. The optimal extraction conditions for Lishi humic acid (LSHA) were determined to be an extraction time of 4.4 h, NaOH concentration of 0.30 mol/L, and liquid-solid ratio of 21 mL/g, while those for Wuhai humic acid (WHHA) were 3.1 h, 0.21 mol/L, and 12 mL/g, respectively. Under these optimal conditions, the true yield values closely matched the predicted value obtained from the model optimization. Comparative analysis of the HAs revealed similarities in their chemical properties, including the degree of aromaticity, molecular weight, and distribution of functional groups. The aromaticity of WHHA was higher compared to that of LSHA. The higher hydrophilic-hydrophobic index of LSHA contributed to its relatively high biological activity compared to that of WHHA. Both humic acids belong to terrestrial humic acids. The results of the study provide a reference for further application of humic acid.

Mitigating the Accumulation of Mercury (Hg) and Lead (Pb) through Humic Acid Application under Aquaponic Conditions Using Watercress (Nasturtium officinale R. Br.) as a Model Plant.

In aquaponic farming, there is a potential risk that heavy metals will contaminate the water, which can lead to heavy metal accumulation in the plants. Our research investigated the accumulation of mercury (Hg) and lead (Pb) under aquaponic conditions and the effect of their increased presence on the uptake of other macro- and micronutrients using watercress (Nasturtium officinale) as a model plant. The potential modifying effect of humic acid on heavy metal accumulation was also investigated. Adding Hg and Pb increased the mercury and lead levels of the watercress plants to over 300 µg kg-1, while the addition of humic acid significantly reduced the concentration of both mercury and lead in the plants compared to plants treated with heavy metals alone, from 310.647 µg kg-1 to 196.320 µg kg-1 for Hg and from 313.962 µg kg-1 to 203.508 µg kg-1 for Pb. For Fe and Mn, higher values were obtained for the Hg + humic acid treatments (188.13 mg kg-1 and 6423.92 µg kg-1, respectively) and for the Pb + humic acid treatments (198.26 mg kg-1 and 6454.31 µg kg-1, respectively). Conversely, the Na, K, Cu levels were lower compared to those in plants treated with heavy metals alone. Our results demonstrated that watercress can accumulate mercury, leading to high levels, even above food safety standards, highlighting the importance of water quality control in aquaponic systems. Furthermore, these results suggest that watercress could be used as a natural filter in recirculation systems. The addition of humic acid significantly reduced the accumulation of heavy metals and altered the element content in the plant.

Effect of Exogenous Application of Humic Acid, GA3 and Vermiwash on Growth, Yield and Quality of Cabbage (Brassica oleracea var. capitata L.) under Valley Condition of Srinagar Garhwal

The effect of exogenous application of humic acid, GA3 and vermiwash on the growth, yield and quality of cabbage was studied in a field experiment. The experiment was conducted in a randomized block design at the Horticultural Research Centre, Chauras Campus, H.N.B. Garhwal University, Srinagar, Uttarakhand, with three replications and ten treatments. All of the growth, yield and quality contributing characteristics of cabbage were found to be significant. The growth parameters at 30, 45 DAT and at harvest were found to be maximum under T9 (GA3 @ 150 ppm). Yield parameters were found to be highest in T9 (GA3 @ 150 ppm) total plant weight (2188.67 g), average weight of head (1454.33 g), yield per hectare (321.43 q) whereas dry weight of head (10.00 g) in T6 (Vermiwash @ 100%), head diameter (18.98 cm) and core diameter (4.53 cm) in T8 (GA3 @ 100 ppm) and core length (8.62 cm) in T1 (Humic acid @ 100 ppm). Quality parameters were found to be highest under T6 (Vermiwash @ 100%) for head compactness (35.39%), whereas total soluble solids (5.20 0Brix) in T3 (Humic acid @ 200 ppm) and ascorbic acid (56.07 mg) in T1 (Humic acid @ 100 ppm). Economic parameters were found to be highest under T6 (Vermiwash @ 100%) for cost of cultivation (1,92,510 ₹/ha), gross return (10,66,030 ₹/ha) and net return (8,73,520 ₹/ha). Hence, it may be suggested that concentration of 150 ppm GA3 could use for enhancing the production of cabbage under subtropical condition of Srinagar Garhwal

The alleviating effect on the growth, chlorophyll synthesis, and biochemical defense system in sunflowers under cadmium stress achieved through foliar application of humic acid

BackgroundWith the progress of industrialization and urbanization, cadmium (Cd) pollution in farmland is increasingly severe, greatly affecting human health. Sunflowers possess high resistance to Cd stress and great potential for phytoremediation of Cd-contaminated soil. Previous studies have shown that humic acid (HA) effectively mitigates plant damage induced by Cd; however, its alleviating effects on sunflower plants under Cd stress remain largely unknown.ResultsWe employed four different concentrations of HA (50, 100, 200, and 300 mg L−1) via foliar application to examine their ability to alleviate Cd stress on sunflower plants' growth, chlorophyll synthesis, and biochemical defense system. The results revealed that Cd stress not only reduced plant height, stem diameter, fresh and dry weight, and chlorophyll content in sunflower plants but also altered their chlorophyll fluorescence characteristics compared to the control group. After Cd stress, the photosynthetic structure was damaged and the number of PSII reactive centers per unit changed. Application of 200 mg L−1 HA promotes sunflower growth and increases chlorophyll content. HA significantly enhances antioxidant enzyme activities (SOD, POD, CAT, and APX) and reduces ROS content (O2−, H2O2 and −OH). Totally, Application of 200 mg L−1 HA had the best effect than other concentrations to alleviate the Cd-induced stress in sunflower plants.ConclusionsThe foliar application of certain HA concentration exhibited the most effective alleviation of Cd-induced stress on sunflower plants. It can enhance the light energy utilization and antioxidant enzyme activities, while reduce ROS contents in sunflower plants. These findings provide a theoretical basis for using HA to mitigate Cd stress in sunflowers.

The Role of Some Biostimulants in Improving the Productivity of Orange

One of the environmental problems that affects negatively orange productivity is drought because it greatly minimizes the growth attributes, photosynthetic process, water uptake, percentage of fruit set, and productivity; meanwhile, it raises the rates of respiration and transpiration, as well as the premature and preharvest fruit drop percentages. In addition, drought creates osmotic stress, affects the relationship between plants and water, reduces the amount of water in shoots, and prevents plant cell development and expansion. It is very important to search for a solution to minimize the effect of drought stress; therefore, the present study has investigated the effect of the application of humic acid (HA) at 0, 1 and 2 kg per tree and spraying of seaweed extract (SWE) at 0.2, 0.3 and 4% in combination with moringa leaf extract (MLE) at 2, 4 and 6%, respectively, on the productivity, fruit quality and nutritional status of navel orange cv. Washington during the 2022 and 2023 seasons. The results proved that the application of the biostimulants individually or in combination significantly positively changed the vegetative growth, productivity, fruit quality parameters and leaf mineral content of macro- and micronutrients of the treated trees compared to untreated trees. The superior treatments which gave the best results were 2 kg HA + 0.4% SWE + 6% MLE followed by 2 kg HA + 0.3% SWE + 4% MLE over the rest of the applied treatments.

Soil Solution Properties of Tropical Soils and Brachiaria Growth as Affected by Humic Acid Concentration

The soil solution is the compartment where plants uptake nutrients and this phase is in equilibrium with the soil solid phase. Changes in nutrient content and availability in the soil solution can vary among soil types in response to humic acid concentrations, thereby affecting Brachiaria growth. However, there are no studies demonstrating these effects of humic acid application on different soil types and how they affect Brachiaria growth. Thus, the aim of this study was to evaluate the effects of humic acid concentrations (0, 5, 10, 25, and 60 mg kg−1 carbon-humic acid) on Brachiaria brizantha growth and soil solution properties of contrasting tropical soils. Plants were grown for 35 days in greenhouse conditions in pots containing Sandy Entisol, Clayey (Red Oxisol), and Medium Texture (Red-Yellow Oxisol). Soil solution was assessed for pH, electrical conductivity (EC), carbon, and nutrient content. Shoot and root dry matter, as well as macro and micronutrients accumulation in the shoot, were determined. In a soil type-dependent effect, pH, EC, and concentrations of nutrients in solutions changed in response to carbon-humic acid concentration. In the less-buffered soils, Sandy Entisol and Red-Yellow Oxisol, the addition of 30–40 mg kg−1 carbon-humic acid increased root proliferation by 76–89%, while Brachiaria biomass produced in all soils increased by approximately 30%. Levels of carbon in solution were high (>580 mg L−1) and varied depending on the investigated soil type. Though solution carbon contents did not appear to be a driving factor controlling the positive effects of humic acid concentrations on Brachiaria dry matter, there was a direct relationship between other properties and nutrient content in the soil solution, and Brachiaria dry matter production.

Co-Application of Coated Phosphate Fertilizer and Humic Acid for Wheat Production and Soil Nutrient Transport

The application of a diammonium phosphate coating effectively mitigates direct contact between the phosphate fertilizer and the soil, thus minimizing phosphorus fixation. Humic acid holds a pivotal role in augmenting soil quality and activating the soil’s phosphorus reserves. Notably, when combined with humic acid, diammonium phosphate significantly enhances the utilization efficiency of phosphate fertilizer. However, there is a paucity of literature exploring the dynamics of nutrient transport in soil when humic acid is paired with coated phosphate fertilizers. To assess the impact of the combined application of coated diammonium phosphate and humic acid on wheat yield enhancement, we conducted pot experiments along with leaching and ammonia volatilization simulation tests, aiming to elucidate the effects of this combination on nutrient transport. The study explored the effects of three distinct treatments: coated diammonium phosphate (CP), coated diammonium phosphate combined with humic acid (PHA), and coated diammonium phosphate combined with humic acid (CPHA). The investigation focused on analyzing their impacts on wheat yield, ammonia volatilization, soil-available phosphorus, nitrate nitrogen, ammonium nitrogen, soil-available potassium, as well as the mobilization and transport of calcium and magnesium in the soil. (1) Compared to the P treatment, the PHA and CP treatments significantly increased grain yield by 17.2% and 13.5%, respectively. The PHA treatment also increased effective panicle number by 12.9%. Overall, the CP, PHA, and CPHA treatments improved grain yield by 13.5%, 17.2%, and 19.1% compared to the P treatment. (2) The CP and PHA treatments reduced available phosphorus by 95.6% and 49.2%, calcium by 2.0% and 67.0%, and magnesium by 11.6% and 46.1% compared to the P treatment. Ammonium nitrogen decreased by 37.0% and 64.3%, while nitrate nitrogen increased by 14.0% in CP and slightly decreased by 0.8% in PHA. In the leaching solution, PHA and CP treatments reduced available phosphorus by 96.7% and 62.5%, increased calcium by 5.0% and 78.9%, decreased ammonium nitrogen by 2.2% and 43.4%, and decreased nitrate nitrogen by 10.6% and 13.0%. The PHA and CPHA treatments increased available phosphorus in the 0–20 cm soil layer by 1.4 times and 25.8%, respectively. (3) The CP treatment reduced ammonia volatilization by 87.0% compared to the P treatment, while the CPHA treatment further reduced it by 87.5% compared to the PHA treatment. The application of coated diammonium phosphate efficiently delays nutrient release and reduces nutrient leaching in the soil. Additionally, the integration of humic acid significantly improves the availability of phosphorus in the soil, minimizing phosphorus loss. Notably, the combined application of humic acid and coated diammonium phosphate leads to a significant increase in soil phosphorus content, subsequently enhancing soil nutrient availability, conserving fertilizer, and ultimately resulting in an improved wheat yield.

Titanium Nanoparticle and Humic Acid Applications Improve Seed Germination, Growth Development, and Phytochemical Contents of Lettuce (Lactuca Sativa) Plants

Titanium Nanoparticle and Humic Acid Applications Improve Seed Germination, Growth Development, and Phytochemical Contents of Lettuce (Lactuca Sativa) Plants

Effects of humic acid application on bacterial diversity under maize cultivation

AbstractThe fundamental ecosystem processes in soil are regulated by microbial communities, and community diversity is implicated by soil environmental conditions. Humic acid (HA) improves soil quality and fertility, stimulating the microbial environment, but the detailed effects remain poorly understood. We investigated the effects of HA rates on soil bacterial diversity, particularly on species richness and community composition in the rhizosphere of corn (Zea mays). Inorganic fertilizer (T2), HA 0.5% (T3), HA 1.0% (T4), HA 1.5% (T5), and HA 2.0% (T6) were applied in soil. Initial soil (O1) and control after harvesting (T1) were included. A total of 3601 operational taxonomic units were captured from the overall sample, and analysis of 16S ribosomal ribonucleic acid amplicon sequencing data indicated that HA did not notably impact species richness. Intriguingly, HA induced changes in bacterial community composition, along with the relative prevalence of specific taxa. Certain associations between soil chemical properties and abundance distribution have been uncovered. Notably, exchangeable Mg2+, Ca2+, and available phosphorus were strongly related to the relative abundance of bacterial phyla. Furthermore, HA potentially shaped the specific bacterial taxa, as the application of HA at different rates had distinct effects on the member of bacterial abundance of each taxon. These findings enhance our understanding of communities potentially being increased or shifted by HA rate addition in short‐term corn cultivation.

Humic acid and grafting as sustainable agronomic practices for increased growth and secondary metabolism in cucumber subjected to salt stress

Salinity stress poses a significant treat to crop yields and product quality worldwide. Application of a humic acid bio stimulant and grafting onto tolerant rootstocks can both be considered sustainable agronomic practices that can effectively ameliorate the negative effects of salinity stress. This study aimed to assess the above mentioned ameliorative effects of both practices on cucumber plants subjected to saline environments. To attain this goal a factorial experiment was carried out in the form of a completely randomized design with three replications. The three factors considered were (a) three different salinity levels (0, 5, and 10 dS m−1 of NaCl), (b) foliar application of humic acid at three levels (0, 100, and 200 mg L−1), and (c) both grafted and ungrafted plants. Vegetative traits including plant height, fresh and dry weight and number of leaf exhibited a significant decrease under increasing salinity stress. However, the application of humic acid at both levels mitigated these effects compared to control plants. The reduction in relative water content (RWC) of the leaf caused by salinity, was compensated by the application of humic acid and grafting. Thus, the highest RWC (86.65%) was observed in grafting plants with 0 dS m−1 of NaCl and 20 mg L−1 of humic acid. Electrolyte leakage (EL) increased under salinity stress, but the application of humic acid and grafting improved this trait and the lowest amount of EL (26.95%) was in grafting plants with 0 dS m−1 of NaCl and 20 mg L−1 of humic acid. The highest amount of catalase (0.53 mmol H2O2 g−1 fw min−1) and peroxidase (12.290 mmol H2O2 g−1 fw min−1) enzymes were observed in the treatment of 10 dS m−1 of NaCl and 200 mg L−1 humic acid. The highest amount of total phenol (1.99 mg g−1 FW), total flavonoid (0.486 mg g−1 FW), total soluble carbohydrate (30.80 mg g−1 FW), soluble protein (34.56 mg g−1 FW), proline (3.86 µg g−1 FW) was in grafting plants with 0 dS m−1 of NaCl and 200 mg L−1 of humic acid. Phenolic acids and phenylalanine ammonia lyase (PAL) and polyphenol oxidase (PPO) enzymes increased with increasing salinity and humic acid levels. Contrary to humic acid, salt stress increased the sodium (Na+) and chlorine (Cl−) and decreased the amount of potassium (K+) and calcium (Ca2+) in the root and leaf of ungrafted cucumber. However, the application 200 mg L−1 humic acid appeared to mitigate these effects, thereby suggesting a potential role in moderating physiological processes and improving growth of cucumber plants subjected to salinity stress. According to the obtained results, spraying of humic acid (200 mg L−1) and the use of salt resistant rootstocks are recommended to increase tolerance to salt stress in cucumber. These results, for the first time, clearly demonstrated that fig leaf gourd a new highly salt-tolerant rootstock, enhances salt tolerance and improves yield and quality of grafted cucumber plants by reducing sodium transport to the shoot and increasing the amount of compatible osmolytes.