Foliar Application Of Humic Acid Research Articles

EFFECT OF HUMIC ACID AND MAXIGROW (ORGANIC FERTILIZER) ON GROWTH, FLOWERING AND YIELD OF SNAKE CUCUMBER (CUCUMIS MELO. L)

ABSTRACT: A field trial was implemented at the research center field at general directorate of agriculture, Dohuk Governorate, Iraqi Kurdistan region in summer season of (2022-2023) to find out the impact of foliar application of humic acid at three levels (0, 2, and 4) ml L-1 and Maxigrow (an organic fertilizer) with three levels (0, 1, and 2) ml L-1 and their combinations on outgrowth, flowering and harvest of local snake cucumber. The experiment was organized following a randomized complete block design (RCBD) including three replicates. The data displayed that the individual dose of humic acid at (4) ml.L-1 significantly enhanced foliage traits [number of branches, stem diameter (cm), Leaf area (cm2), plant fresh weight (g), and chlorophyll content (SPAD)] as well as increased flowering characters [number of flowers after 30 days and number of flowers after 40 days] and yielded components [fruit length (cm), fruit diameter (cm), and total yield (ton.ha-1)]. The same profound effect was exhibited by the singular dose of Maxigrow at concentration (2) ml.L-1. However, the highest mean values were produced from humic acid at concentration (4) ml.L-1 in combination with Maxigrow at concentration (2) ml.L-1 in comparison with control. The increased level of humic acid and Maxigrow is advised for organic productivity of local snake cucumber.

Effect of Soil and Foliar Application of Humic Acid on Nutrient Uptake, Grain and Straw Yield of Black Gram (Vigna mungo L.) under Inceptisols

Black gram is a type of legume that is widely cultivated and consumed in various parts of the world. It is believed to have originated in the Indian subcontinent and is one of the oldest cultivated legumes in the world. The field experiment was carried out to during kharif season of the year 2022 at departmental farm of Soil Science and Agricultural Chemistry, College of Agriculture, Latur. The experiment was laid out in randomized block design with three replications and eight treatments viz., T1 (RDF), T2 (RDF + Foliar application of humic acid @ 0.2 % at 20 & 35 DAS), T3 (RDF + soil application of humic acid @ 10 kg ha-1), T4 (RDF + soil application of humic acid @ 15 kg ha-1), T5 (RDF + soil application of humic acid @ 20 kg ha-1), T6 (T3 + foliar application of humic acid @ 0.2% at 20 & 35 DAS), T7 (T4 + foliar application of humic acid @ 0.2% at 20 & 35 DAS), T8 (T5 + foliar application of humic acid @ 0.2% at 20 & 35 DAS). The field study indicated that the nutrient uptake and content  and grain and straw yield of black gram crop were significantly influenced due to soil and foliar application of humic acid and RDF. The uptake of N, P and K  were recorded at harvest. Significant and maximum uptake of  N, P and K were noticed with application of treatment T8 (RDF + soil application of humic acid @ 20 kg ha-1+ foliar application of humic acid @ 0.2% at 20 and 35 DAS), whereas the T1 (RDF) showed least values. grain and straw yield significantly affected due to T8 (RDF + soil application of humic acid @ 20 kg ha-1 + foliar application of humic acid @ 0.2% at 20 and 35 DAS) and the lowest grain and straw yield were recorded in T1 (RDF). Thus, it can be concluded that the soil and foliar application of humic acid increase the nutrient uptake and grain and straw yield. The significantly superior result recorded by treatment T8 (RDF + soil application of humic acid @ 20 kg ha-1 + foliar application of humic acid @ 0.2% at 20 and 35 DAS) next to this treatment T7 (RDF + soil application of humic acid @ 10 kg ha-1 + foliar application of humic acid @ 0.2% at 20 and 35 DAS) was best option. The significant increase in grain and straw yield of black gram was due to application of RDF with soil and foliar application of humic acid which mitigates scarcity, increased absorption effectively and increased photosynthetic activity which leads to higher grain and straw yield.

Foliar Application of Humic Acid on Growth and Biomass Improvement of Bok Choy and Red Leaf Lettuce

Humic acid (HA) is an organic product that is applied as a foliar spray to stimulate the growth and health of various horticultural and agricultural crops. However, its impact on the growth, yield, and health of exotic vegetable crops such as bok choy (Brassica rapa L.) and red leaf lettuce (Lactuca sativa L.) needs to be further explored. The current study aimed to assess the impact of foliar application of HA on the growth and biomass production of bok choy and red leaf lettuce. Notably, the foliar spray of 2% HA resulted in increased plant height, leaf length and width, leaf area, and overall plant biomass production in both bok choy and red leaf lettuce compared to the control group. However, the foliar spray of HA did not significantly affect the shoot and root length, nor the number of leaves of bok choy compared to a control. Moreover, the application of HA significantly improved the shoot length and the number of leaves of red leaf lettuce compared to the control group. Hence, HA emerges as a promising natural resource for enhancing agricultural production sustainably. It could serve as a superior growth enhancer for both bok choy and red leaf lettuce.

Exploring the Effect of Humic Acid on Chlorophyll Levels in Japanese Mint under Drip and Flood Irrigation Amidst Water and Nutrient Constraints

A field experiment on Mentha (Mentha arvensis L.) was conducted during the spring seasons of 2022 and 2023 at G.B. Pant University of Agriculture and Technology, Pantnagar. The objective was to investigate the impact of foliar spray of humic acid on SPAD values under conditions of limited water and nutrients. The experiment comprised two drip irrigation levels (80% and 100% of crop evapotranspiration) and four nutrient management practices. These practices included: 25% NPK basal + 75% NPK fertigation, 50% NPK basal + 50% NPK fertigation, No basal + 75% NPK fertigation + three foliar sprays of humic acid at 0.3%, and 25% NPK basal + 50% NPK fertigation + three foliar sprays of humic acid at 0.3%. The experiment was laid out in a randomized block design with three replicates (factorial), and an extra control was included. The control followed conventional practices, where the crop received recommended doses of fertilizers (N: P2O5: K2O @ 120:60:40 kg/ha) and was irrigated at an IW: CPE ratio of 1.2 with a 5 cm irrigation depth. Significantly higher SPAD values were observed when the crop was irrigated at 100% ETc level of drip irrigation and with nutrient management practices involving foliar application of humic acid, compared to 80% ETc level of drip irrigation and total NPK supply through chemical fertilizers, respectively. At harvest, crops irrigated at 100% ETc level recorded SPAD readings that were 11.1% and 18% higher than those irrigated at 80% ETc level during 2022 and 2023, respectively. The humic acid application helped to maintain the SPAD values even after a 25% reduction in nutrient dosage. SPAD values for control were significantly lower than the combination of best nutrient management practices with either 80 or 100% ETc level of drip irrigation.

Effect of Humic Acid from Vermicompost and Commercial Source on Growth, Yield and Quality of Groundnut (Arachis hypogea L.)

A pot culture experiment was conducted in the year 2017 at Main Agricultural Research Station, University of Agricultural Sciences, Dharwad to study the impact of soil and foliar application of humic acid from vermicompost and commercial source on growth, yield and quality parameters of groundnut variety GPBD-4 by adopting completely randomized block design with thirteen treatments and three replications. The highest plant height (36.83 cm), LAI (0.96) and relative chlorophyll content (34.82) was recorded in the treatment which received soil application of humic acid from vermicompost @ 20 kg ha-1 in combination with the foliar spray of 0.2% at 30 DAS. Similar trend was observed in yield and quality parameters of groundnut. Significantly highest number of pods plant-1 (24.00), pod yield plant-1 (14.80 g plant-1), oil content (46.12%) and crude protein content (25.38%) was also recorded in the same treatment. The results revealed that there is a statistical increase in the periodical observation, yield and quality of groundnut with the additional application of humic acid extracted from vermicompost over the recommended package of practice.

Agro-Physiologic Traits of Soybean in Response to Biological Fertilizers

Plant nutrition is one of the most important environmental factors affecting the quantitative and qualitative yield of crops. This study investigated the effect of rhizobium and azospirillum inoculum and foliar application of humic acid and nutrients of molybdenum, cobalt, and boron on node formation, yield, yield components, and morpho-phenological traits of soybean (Saman cultivar). The experiment was carried out in a factorial randomized complete block design at Golestan Agricultural and Natural Resources Research Center in 2018 and 2019 in three replications. The results showed that experimental treatments had a significant effect on the measured traits. Most of the measured traits, including yield, under the influence of seed treatment with bacteria azospirillum and cobalt, molybdenum, boron showed more increase than the control. It was found that under humic treatment, application of bacteria and nutrients can be effective on improvement of seed yield, so the highest seed yield mean (3268 kg/ha) was obtained by humic acid + Rhizobium+Azospirillum + Co+Mo+B treatments. Also, the highest protein yield mean was obtained by humic acid + Rhizobium + Co+Mo+B treatments (1103 kg/ha) and highest mean of oil yield was obtained by humic acid + Rhizobium+Azospirillum + Co+Mo treatments (577 kg/ha). Overall, the results of this study confirmed the efficiency of nitrogen-fixing bacteria as well as foliar application of micronutrients in increasing soybean yield per unit area.

Effect of Soil and Foliar Application of Humic Acid and Brassinolide on Morpho-physiological and Yield Parameters of Black Gram (Vigna mungo)

During the Kharif season of 2022-2023 at Lovely Professional University, Jalandhar, Punjab, a field experiment was conducted to investigate the “Effect of soil and foliar application of humic acid and brassinolide on morpho-physiological and yield parameters of Black gram (Vigna mungo).” The experiment was designed using a Randomised Block Design (RBD) with three replications and eight treatments. Compared to the other treatments, RDF + humic acid 0.1% + brassinolide 0.1ppm (foliar application) was the optimal treatment for most morphological and yield parameters. Plant height (cm), number of primary branches per plant, number of secondary branches per plant, dry matter accumulation (g), chlorophyll Index (SPAD), and leaf area (cm2) were highest under T7- RDF + humic acid 0.1%+brassinolide 0.1ppm (foliar applied) conditions. Minimum phenological observations were recorded for soil and foliar applications of brassinolide, including days to first flowering, days to 50 percent flowering, and days to pod initiation. Number of pods /plant, pod length(cm), pod weight (g), no. of seeds /pod, test weight (g), seed yield (q/ha), stover yield (q/ha), and harvest index (%) were significantly influenced by the T7 and recorded higher values. The increased seed yield may be attributable to plants treated with growth regulators remaining physiologically more active to accumulate sufficient food reserves for developing blossoms and seeds.

Effect of Humic acid foliar application on growth, yield, and quality of some garlic genotypes under Aswan Governorate

Effect of Humic acid foliar application on growth, yield, and quality of some garlic genotypes under Aswan Governorate

Soybean (Glycine max L.) Yield and Yield Component Under Different Planting Time and Foliar Application of Humic Acid

A triplicate field experiment laid out in randomized complete block design was conducted to evaluate the effect of foliar application of humic acid rates (HAR) at Bakrajo, Sulaimani which is  (located at 35°32'52.8"N and 45°21'16.6"E) belongs to Kurdistan region of Iraq with the silty clay soil type. Five different Humic Acid rates (HAR) which were (0 (control), 2,4,6,8 g/L) and two cultivation period (CP) which were cultivation Period 1 (CP1) on 15 May 2022 and cultivation Period 2 (CP2) on 1st of June 2022. The effect of foliar Humic acid rates application methods was highly significant on the Pod No./ Plant, Empty Pod/Plant, Seed Weight / Plant (g) and yield (kg/ha) and significant on the 1000 Seed Weight (g). While, the effect of cultivation period (CP) was highly significant only for the Pod No./ Plant  and the insignificantly affected the other parameters including Empty Pod/Plant, Seed No./ Pod, 1000 Seed Weight (g), Weight / Plant (g) and yield (kg/ha). The maximum Pod No./ Plant, Empty Pod/Plant, Seed Weight / Plant (g) and yield (kg/ha) and significant on the 1000 Seed Weight (g) were observed under foliar application of HAR of 6 g/L and the best cultivation period for sowing humic acid was (CP1) which was on 15 May.

Effect of Humic acid and Ascorbic acid on Growth and Yield of Onion (Allium cepa L.) under Valley Conditions of Garhwal Himalaya

An experiment was conducted at Horticultural Research Center, Chauras Campus, Department of Horticulture, H.N.B Garhwal University, Srinagar (Garhwal), Uttarakhand to assess the impact of humic acid and ascorbic acid on growth and yield of onion bulb. The experiment was formulated with foliar application of humic acid 0, 30, 50 and 70 ppm and Ascorbic acid 0, 25, 40 and 60 ppm concentration at 30 and 45 days after transplanting with three replications under randomized block design. The maximum plant height (39.44 cm), number of leaves per plant (10), highest bulb length (5.93 cm), bulb diameter (5.47 cm), bulb fresh weight (88.20 g), bulb dry weight (13.88 g) and bulb yield per plot (6.39 kg) were obtained with the spray of Humic acid 70 ppm + Ascorbic acid 40 ppm (T15), while minimum were recorded with control (T1).

EFFECT OF PLANTS SPACE AND FOLIAR APPLICATION OF HUMIC ACID IN SEED YIELD AND BIOCHEMICAL COMPOSITION OF GOAT PEA (SECURIGERA SECURIDACA L.)

A field experiment ensued during the winter crop season 2018–2019 at the District Baqubah, Diyala Governorate, Iraq, to study the effects of three plant spacing (20, 40, and 60 cm) and foliar application of humic acid with four concentrations (0, 10, 20, and 40 L ha-1 ) on seed yield-related traits and active ingredients of goat pea (Securigera securidaca L.). The recorded data underwent statistical analysis using a randomized complete block design (RCBD) with factorial arrangement. The results showed that the plant spacing of 60 cm was superior in the percentage of oil and the total content of glycosides in the seeds, amounting to 3.84% and 27.86 mg g-1 , respectively, and the plant distance of 40 cm was superior in the seeds’ total phenol content (1.23 mg g-1 ). As for 20 cm, it was excellent in the oil yield (15.56 kg ha-1 ). The spraying with humic acid at the rate of 20 L ha-1 provided the highest percentage and harvest of oil and total phenol content, reaching 3.69%, 9.30 kg ha-1 , and 1.21 mg g-1 , respectively. The interaction between the plant distance (60 cm) and foliar application of humic acid (10 L ha-1 ) showed a significant increase in the percentage of oil, amounting to 3.92%. The interaction between the plant distance (40 cm) and foliar application of humic acid (20 L ha-1 ) provided a substantial increase in the total phenol content of seeds (1.25 mg g-1 ).

EFFECT OF ORGANIC AND MINERAL FERTILIZATION AND HUMIC ACID APPLICATION ON INCREASING THE FLAVONOID CONTENT IN MORINGA OLEIFERA LEAVES

The presented research carried out in the growing season of 2020 at the Department of Horticulture and Landscape, College of Agriculture, University of Anbar, Iraq, investigated the impact of mineral (chemical) and organic (birds) fertilization and foliar application of the humic acid on the active substances of the moringa (Moringa oleifera) plant leaves. The treatments included an organic fertilizer (300 g plant-1 ), mineral fertilizer DAP (225 g plant-1 ), and humic acid (3000 ppm). The experiment ran in a randomized complete block design (RCBD) with three replications. Results revealed that adding organic and mineral fertilizers and foliar application of humic acid affected and increased flavonoids significantly in moringa plant leaves, such as, six flavonoid components, i.e., catechin, quercetin, luteolin, rutin, apigenin, and kaempferol, amounting to 73.83, 21.51, 3.344, 20.55, 7.53, and 2.09 µg L -1 , respectively, compared with the control treatment (2.56, 3.22, 1.304, 2.25, 1.88, and 0.29 ppm, respectively).

The Effect of a Preparation Containing Humic Acids on the Growth, Yield, and Quality of Strawberry Fruits (Fragaria × ananassa (Duchesne ex Weston) Duchesne ex Rozier)

Humic acids are plant biostimulants, which can be used in horticulture as an effective and relatively inexpensive alternative to chemical means of production. The aim of the study was to assess how the fertiliser containing humic acids affected the growth, yield, and quality of strawberry fruits. In 2021, an experiment was conducted on two-year-old strawberry bushes (Fragaria× ananassa (Duchesne ex Weston) Duchesne ex Rozier) of the ‘Rumba’ cultivar growing on a horticultural farm in northern Wielkopolska, Poland. During the growing season, the soil was fertilized by the mineral fertilization and the bushes were sprayed two, three, or four times with the Humi Brown Gold fertiliser containing humic acids. In the experiment, the soil enzymatic activity, biometric parameters of strawberry leaves, fruit yield and fruit quality was assessed. It was determined that, in the experimental treatments where foliar fertilisation had been applied, the activities of proteases and dehydrogenases as well as soil respiration increased by more than double and were significantly higher than in the variants where soil fertilisers had been applied. The strawberry bushes treated with the humic acids fertiliser developed more than 60% larger surface leaves, bloomed more intensively and gave a higher yield. Fruits with significantly higher firmness were harvested from such bushes, with higher weight and extract content than those where the soil fertiliser had been applied. The difference was several tens of percent. This leads to the conclusion that the foliar application of humic acids could be an effective alternative to mineral fertilisation in strawberry plantations.

Esponse of Wonderful Pomegranate Cutting to Foliar Application of Humic Acid and Different Growth Medium

The present study was conducted to evaluate the effect of different growing mediums {sand, peat moss, and mix (sand + peat moss 1:1 v/v)} and spraying with 0,100 and 150 mg L-1 of humic acid on vegetative and root parameters of “Wonderful” pomegranate hardwood cuttings at Bakrejo nursery station, Sulaimania city, Iraq in 2021. They were planted in polyethylene black bags on 15-3-2021. Using randomized complete block design within the factorial experiments with three blocks. The results indicated that leaves, roots and shoots number, root wet weight, and root length were increased significantly in peat moss medium. Cuttings grown in a mixed medium showed a significant increase of leaf growth including leaf area, leaf dry weight, and chlorophyll content. In addition, spraying with 100 mgL-1 of humic acid caused a significant increase in the root characteristics, and shoot number compared to the control. Furthermore, the maximum root growth was recorded in the interaction between peat moss medium and applying 100 mgL-1 of humic acid compared to other treatments

Effect of Sulfur Granular Municipal Solid Waste, Humic Acid, and Nano Fe-Oxide on Lead Uptake by Plants in a Calcareous Soil in the Presence of Thiobacillus

Soil poisoning with heavy metals is one of the most significant aspects of environmental research. In the soil treated with Thiobacillus, the effect of sulfur granular municipal solid waste (sulfur granular MSW), humic acid, and nano Fe-oxide on reducing Pb absorption by plants was investigated. Treatments consisted of applying sulfur granular MSW (0 and 30 t/ha), spraying humic acid (0 and 1.5 mmol/L), and using nano Fe-oxide (0 and 2% w/w) in the soil contaminated with Pb (0, 600, and 1200 mg/kg-soil). Plants were collected after 5 months, and the Pb content in the soil and plants was estimated by atomic absorption spectroscopy (AAS). The activity of ascorbate peroxidase (APX) and peroxidases (POX) enzymes were also determined. The use of 30 t/ha of sulfur granular MSW in the Pb-polluted soil reduced Pb concentration in the soil and plant by 13.4% and 15.1 %, respectively, while it increased Fe concentration by 15.2% in the plant. Using nano Fe-oxide (2% w/w) in the Pb-contaminated soil (600 and 1200 mg/kg soil) considerably enhanced Fe content in the plant. Pb absorption by plants was dramatically reduced by foliar application of humic acid. According to the findings of this study, the interaction effects of sulfur granular MSW, nano Fe-oxide, and humic acid significantly reduced the Pb absorption by plants. However, the impacts of soil physico-chemical characteristics and the kind of soil pollutant on plant Pb concentration cannot be ignored.

Effect of Foliar Application of Humic Acid and Zinc Sulfate on Vegetative, Physiological, and Biochemical Characteristics of Physalis alkekengi L. Under Soilless Culture

Effect of Foliar Application of Humic Acid and Zinc Sulfate on Vegetative, Physiological, and Biochemical Characteristics of Physalis alkekengi L. Under Soilless Culture

Effect of Foliar Application of Humic Acid and Nano-NPK on Some Growth Characteristic of Apple Trees Malus Domestica Borkh

This study was carried out in one of the private orchards, which are 20 km away from Kirkuk province in the Altun Kobri area, during the period from May 2021 to August 2021, to study the effect of fertilizing with humic acid at three levels (0, 20, 40) gm and spraying with fertilizer The nano NPK with four levels (0, 1.5, 2.5, 3.5) g.L-1 in some growth characteristics and the yield of apple trees of the local Ibrahimi variety. The experiment was designed according to the design of randomized complete blocks (RCBD), a factorial investigation that included three factors of humic acid and four factors of the compound fertilizer nano NPK and with three replications, the number of treatments in each sector (12) treatments, and with 36 trees included in this experiment, and the treatments were distributed randomly on the experimental units, and for analyzing the data we use the SAS program, and the Duncan polynomial test was adopted under the probability level of 5%. The results showed that the humic acid fertilization gave significant differences in the averages of the studied traits, as the treatment of humic fertilizer at the level (40) gave the highest rate in the following characteristics (the chlorophyll content of the leaves and the proportion of potassium and phosphorous in the leaves). In contrast, the treatment (20) gave the highest rate in Characteristics (the percentage of nitrogen in leaves and leaf area). As for the treatment of spraying with nanocomposite fertilizer with a concentration of (3500), it achieved the highest rate in the characteristics (the content of chlorophyll in the leaves and the percentage of nitrogen, phosphorous and potassium in the leaves), while it gave the concentration (2500) the highest rate in the leaf area. The results also showed that the binary interaction achieved significant differences in the studied traits, as treatment (40) of humic fertilizer and (3500) of the nano-complex fertilizer achieved the highest rate in most of the studied features, namely (leaf area, leaf content of chlorophyll and phosphorous percentage in leaves).

The biological and biochemical composition of wheat (Triticum aestivum) as affected by the bio and organic fertilizers

Microorganisms and organic compounds (humic and fulvic acid) offer viable alternatives to insecticides and mineral fertilizers. Even though many studies have shown the effects of biofertilizers and organic substances separately, little information is available on plant responses to the combined application of these bio-stimulants, even though these biological inputs have a high potential for simultaneous action. A two-year (2020/21–2021/22) field experiment was conducted to investigate the impact of organic and biofertilizers application on the growth, yield, and biochemical attributes of wheat (cv. Misr-1). Pre-planting, wheat seeds were inoculated with two biofertilizers including Mycorrhizae, and Azotobacter, and their combination (MIX), and control (un-inoculation) were considered the main plot factor. The subplot factor contained the foliar sprays of humic acid, fulvic acid, and control (no spray). The results revealed that the seed inoculation with mycorrhizae and azotobacter in combination with foliar-applied humic acid markedly (p ≤ 0.05) affected the growth, yield, and seed biochemical composition of wheat. Combination of mycorrhiza and azotobacter significantly (p ≤ 0.05) increased) plant height (100 cm), crop growth rate (18.69 g), number of spikelets per spike (22), biological yield (13.4 ton ha-1), grain yield (5.56 ton ha-1), straw yield (8.21 ton ha-1),), nitrogen (2.07%), phosphorous (0.91%), potassium (1.64%), protein content (12.76%), starch (51.81%), and gluten content (30.90%) compared to control. Among organic fertilizers, humic acid caused the maximum increase in plant height (93 cm), crop growth rate ( 15 g day-1 m-2),1000 grain weight (51 g), biological yield ( 11ton ha-1), grain yield (4.5 ton ha-1), protein content (11%), chlorophyll content (46 SPAD), and gluten (29.45%) as compared to all other treatments. The foliar application of humic acid combined with the mycorrhizae or azotobacter seed inoculation was efficient to induce wheat vegetative growth development, as well as yield and its components.

Foliar Application of Humic Acid with Fe Supplement Improved Rice, Soybean, and Lettuce Iron Fortification

Iron (Fe) deficiency in humans, particularly in pregnant women and children, is caused by inadequate dietary Fe intake and is a global nutritional problem. Foliar fertilization is a cost-effective agronomic approach to increase Fe bioavailability in the human diet. We evaluated the effects of different Fe formulations (Fe-citrate, Fe-EDTA, FePO4, nano-Fe oxide, and humic acid (HA) with and without Fe) on growth, yield, and Fe accumulation in the edible parts of rice, soybean, and lettuce crops. Rice and soybean received multiple sprays at different growth stages, i.e., tillering, anthesis, and grain filling in rice as well as flowering and pod filling in soybean, while lettuce received a single foliar spray. In rice and soybean, the seed Fe accumulation increased proportionally as the number of foliar sprays increased; however, the grain yield did not show this relationship. Among Fe treatments, HA+Fe was identified as the best treatment in terms of improving overall plant growth, yield, and Fe accumulation in the edible parts of all three crops. We found a significant positive correlation between the shoot/stover Fe content and the grain Fe content, but HA+Fe showed an opposite trend, i.e., minimal Fe retention in shoots/stovers and maximal increases in the seed Fe contents in both crops, suggesting better Fe mobilization efficiency from shoots to developing seeds. We strongly recommend that HA with Fe can be used as a foliar Fe fertilizer to improve the growth, yield, and Fe status in different crops.

Response of foliar application of humic acid and micronutrient mixture on growth and grain yield of maize crop

The efficiency of humic acid (HA) and micronutrient (MN) mixtures as a source, either separately or in combination, was studied to increase the productivity and growth of maize (Zea mays L.). The research was carried out in the College of Agriculture, Azamgarh, Uttar Pradesh, India during the spring season of 2022. The treatments were replicated three times in a randomized complete block design. The HA and MN mixtures were sprayed separately at 0.2% and 0.4% each. Further, the combination of HA @ 0.2% + MN @ 0.2% and HA @ 0.4% + MN @ 0.4% was also applied. The application was done by foliar spray twice on 35 and 50 DAS, along with control using water. The result revealed that foliar spraying of HA at 0.4% + MN at 0.4% significantly (P=0.05) improved the height (cm), LAI, and dry matter accumulation (g m-2) of the maize crop. In comparison to the MN combination, HA generally had more maize growth and yield. A foliar spray with a combination of HA and MN at 0.4% each could result in a higher grain yield of the maize crop, which recorded a 42.62% higher grain yield than the control. Hence, based on the study, foliar application of the HA+MN mixture at 0.4% could be advised to boost maize crop growth and grain yield during the spring season.