Humic Acid Doses Research Articles

The Effect of Nitrogen and Humic Acid Treatments on Some Characteristics of Faba Bean (Vicia faba L.)

In addition to its agricultural characteristics, the faba bean plant is a remarkable plant due to its L-DOPA content. In this study, In this study, the effects of 3 different humic acid doses (HA0: control, HA1:2 l da-1, HA2:6 l da-1) and nitrogen fertilizer (5 kg da-1) treatments on some characteristics of Lara and Maçka genotypes and L-DOPA content in its flowers were investigated. The trial was carried out in the Strip Plots Trial Design in Samsun in one year. According to the findings, the effect of HA treatments on the amylose content in the seed was found to be statistically significant, and the values obtained from the treatments were equivalent to the control values in other examined properties. It has been determined that there are statistically significant differences between genotypes in many of the characteristics examined; It was determined that the flower yield and the amount of L-DOPA transferred to the tea water were higher in Maçka genotype.

Humic and fulvic acid influence the morphophysiological and biochemical properties of cowpea (Vigna unguiculata) under water deficit

Context Water deficit is a limiting factor in cowpea (Vigna unguiculata) performance. Humic and fulvic acids are organic fertilisers that increase plant productivity and appear as a viable alternative to improve cowpea productivity under water deficit. Aim We evaluated the efficiency of humic and fulvic acid on the morphophysiological and biochemical properties of cowpea subjected to water deficit. Methods The experiment was conducted in a greenhouse. A completely randomised design was adopted in a 5 × 2 factorial scheme with four replications, with five doses of humic and fulvic acid, 0, 4, 8, 12 and 16 mL/L applied to plants irrigated at 100% and 25% of field capacity. Stomatal conductance (gs), water potential (Pw), plant height (H), stem diameter (SD), number of leaves (NL), number of root nodules (NR), fresh and dry weight of the aerial (FMA and DMA) and root (FMR and DMR), total soluble proteins (SP) and total phenolic compounds (PC). Key results Doses of 8 and 12 mL/L increased gs (100–200 mmol m2 s−1), reduced Pw (−0.9 MPa) and NR, increased FMR and DMR (20 and 10 g), SP (8–9 g) in stressed and non-stressed individuals. Conclusions Intermediate doses of humic and fulvic acid (12 mL/L) are recommended for cowpea production in dry regions. Implications Humic and fulvic acid together are viable alternatives for optimising agricultural production and decision making in semi-arid regions.

The role of humic acid from various composts in improving degraded soil fertility and maize yield

Humic acids play a crucial role in ion exchange and metal ion complexes; therefore, they are potentially useful in improving soil fertility and crop yield. This study aimed to explore the role of humic acid (HA) from various composts in improving degraded soil fertility and maize yield. A field experiment was conducted on Inceptisols having low soil organic carbon, nitrogen and available phosphorus contents. Eight treatments of HA formulas and one control were arranged in a randomized block design with three replications. The HA formulas used were combinations of two doses of HA (0.15 and 0.20% of soil on w w<sup>-1</sup> base) and four types of HA (HA extracted from bagasse compost, HA extracted from water hyacinth compost, HA extracted from market waste compost, and commercial HA). The results showed that the HA application increased 16-97% of soil organic carbon, total nitrogen, available phosphorus, exchangeable potassium and calcium compared to the control. The formula of commercial HA at 0.15% was the best treatment for inhibiting soil fertility degradation in agricultural land. The best maize yield of 15.13 t ha<sup>-1</sup> and starch content of 63.54% was obtained from the application of commercial HA at 0.20%.

Effect of Humic acid on the Growth Attributes of Wheat (Triticum aestivum L.) Crop in sandy loam soil of Gwalior region of Madhya Pradesh, India

A field experiment was conducted during Rabi season 2019-2020 to study the Effect of humic acid on the growth and yield attributes of wheat crop in sandy loam soil of Gwalior region of Madhya Pradesh, on Crop Research Centre, School of Agriculture (SoAg.), ITM University Gwalior M.P., India. The experiment was laid out in a Factorial Randomized Block design (F-RBD) replicated three times with three levels of Recommended Dose of Fertilizer (RDF), i.e. (RDF @ 0, 50 and 100 %) and two levels of Humic Acid (HA) (HA @ 500 ppm and 1250 ppm) thereby making eight treatment combinations with 24 plots. Treatments were; T1- Absolute control, T2 -RDF @ 100 %, T3-RDF @ 0 % +HA1 @ 500 ppm, T4-RDF @ 0 % + HA2 @ 1250 ppm, T5-RDF @ 50 % +HA1 @ 500 ppm, T6-RDF @ 50 % +HA2 @ 1250 ppm, T7-RDF @ 100 % +HA1 @ 500 ppm and T8-RDF @ 100 % + HA2 @ 1250 ppm. Among the different levels of Recommended Dose of Fertilizer (RDF) and humic acid were recorded the highest values for all parameters viz; plant population m-2, plant height (cm), numbers of tillers per m-2, numbers of leaves per culm-2, root length (cm), dry weight (g) and fresh weight (g) of the plant under the treatments T8- RDF @ 100 % + HA2 @ 1250 ppm concentration. The means value for all parameters are; plant population m-2 (16.86 and 16.00 at 30 and 60 DAS), plant height (10.03, 58.05 and 76.08 cm at 30, 60 and 90 DAS), numbers of tillers per m-2 (5.88 and 7.02 at 30 and 60 DAS), numbers of leaves per culm-2 (3.90, 4.94 and 3.59 at 30, 60 and 90 DAS), Root length -7.01, 9.00, 11.06 and 12.03 cm, Dry weight of plant-1 0.39, 5.31 and 37.54 g and Fresh weight of plant-1 4.01, 40.01 and 350.71 g in 30, 60 90 DAS and harvest stage.

The Effect of Some Treatments on Seed and Plant on The Agricultural Characteristics of Faba Bean (Vicia faba L.) and The L-DOPA (L-3, 4-Dihydroxyphenylalanine) Content

In this research, 2 different doses of acetic acid (AA: 4%, 40%) were treated the seed before sowing; 2 different doses of humic acid (HA1 :2 L da-1 , HA2 :6 L da-1) and nitrogen (N: 5 kg da-1) treatments to the plant in the field were carried out in Strip-Plots Design in Samsun ecological conditions to determine the effects of faba bean agro-morphological, seed quality and L-DOPA content in flowers. According to the findings obtained, ıt was determined that the seed treatment had a statistically significant effect on the number of branches, pods, biological yield, seed yield and flower yield, and the 4% AA treatment gave better results compared to the control. HA and N as plant treatments showed a statistically significant and negative effect on the number of pods, biological yield and seed yield. The statistical effects of the treatments on the L-DOPA transferred to the herbal tea obtained from the flower were not found significant. However, it was determined that the AA treatment to the seed increased the ratio of L-DOPA in flower compared to the control. Therewithal, when the ratio of flowers was increased from 100 mg to 200 mg while preparing tea, there was an increase in the ratio of L-DOPA transferred to the tea water.

Effects of Sowing Rate and Humic Acid Applications on Some Important Yield and Quality Parameters of Black Cumin (Nigella sativa L.)

Deneme üç tekerrürlü olarak 2019-2020 yılı yazlık yetiştirme döneminde “Tesadüf bloklarında bölünmüş parseller deneme desenine” göre yürütülmüştür. Çalışmanın ana parsellerini ekim normu (1, 2 ve 3 kg da-1) ve alt parsellerini ise hümik asit dozları (Kontrol, 100, 200 ve 400 g da-1) oluşturmuştur. Çalışma sonunda çörek otu bitkisinde tohum verimi, biyolojik verim, bitki boyu, bitki başına kapsül sayısı, kapsüldeki tohum sayısı, bin tohum ağırlığı, hasat indeksi ve sabit yağ oranı gibi parametreler incelenmiştir. Çalışma sonunda bitki boyunun 38.73-47.80 cm, bitki başına kapsül sayısının 3.35-4.90 adet bitki-1, kapsüldeki tohum sayısının 64.94-75.52 adet kapsül-1, bin tohum ağırlığının 2.36-2.54 g, biyolojik verimin 110.42-203.47 kg da-1, tohum veriminin 36.15-50.78 kg da-1, hasat indeksinin % 24.51-37.16 ve sabit yağ oranının % 34.02-39.84 arasında değiştiği belirlenmiştir. Sonuçlara göre Kayseri ili için tohum verimi bakımından en yüksek değerin elde edildiği 2 kg da-1 ekim normu ve 200 g da-1 hümik asit uygulamasının çörekotu üretiminde en uygun miktarlar olduğu söylenebilir.

Combining humic acid with NPK fertilizer improved growth and yield of chili pepper in dry season

This research aimed to study the effect of humic acid and NPK fertilizer (15:15:15) on growth and yield of red chili, and to obtain the most suitable composition of humic acid and NPK fertilizer which gave the best growth and yield. The study used a randomized block design with five replications. The treatments tested were the composition of humic acid and NPK fertilizer: 100% humic acid; 75% humic acid + 25% NPK; 50% humic acid + 50% NPK; 25% humic acid + 75% NPK; and 100% NPK. Data on plant growth and yield were processed by Analysis of Variance, and means were compared using Fisher’s Least Significant Difference test. In addition, data on plant biochemical and soil chemical parameters were determined compositely by mixing leaves taken from sample plants or soil samples into one homogenous sample. Results showed that there was no significant difference in growth and yield of plants treated with 100% humic acid in comparison with those plants treated with 100% NPK. However, in comparison with 100% humic acid, the application of different ratios of humic acid/NPK increased plant chlorophyll contents by 65% - 82% and total sugar by 28% - 71%. The application of humic acid/NPK increased soil fertility by improving soil pH as well as N, P and K. In the combination of humic acid/NPK, the best growth and yield were obtained with the application of 25% humic acid + 75% NPK fertilizers. Therefore, for the sustainability of chili cultivation, the use of humic acid needs to be accompanied with NPK fertilizers at a reduced amount, along with the increase in the dose of humic acid.

Nutritional Value of Different Kenaf Leaves (Hibiscus cannabinus L.) Varieties Enhanced by Using Different Concentrations of Humic Acid

Nutritive value of kenaf leaves encourages researchers to do researching, due to its distinction of some areas like; medicinal plant, source of food for human and as feedstock for animals. The objective of the study is to improve nutritive components of kenaf leaves from different varieties by adding some concentrations of humic acid. The kenaf varieties were FH952, HC95 and HC2 as (V1, V2 and V3), respectively, and humic acid concentrations were 0.0, 0.5, 1.0, and 1.5 g/4L water m-2 as (H0, H1, H2 and H3), respectively. The experiment was conducted at two locations; Grdarasha Field and Ainkawa Research Station in summer season 2021. The results indicated that the FH952 variety recorded highest value for fat, fiber, moisture, carbohydrate and energy content, which were (7.69%, 19.29%, 3.88%, 40.64% and 2629.95 k.cal), respectively. While, highest value for protein and ash contents were recorded by HC95 and HC2 which were (16.57% and 14.75%), respectively. In addition, 1.5 g/4L water m-2 of humic acid application showed an increase in leave contents including; protein 16.68%, fiber 20.25%, moisture 4.11%, carbohydrate 40.47% and energy 2541.52 k.cal. However, from the interaction factors V2H3 had maximum protein by almost (17.23%), and carbohydrate (40.76%). Also, maximum fat was found by (7.15%) and the energy (2708.01k.cal), with the VIH3 treatment. These facts showed that applying other doses of humic acid may cause to enhance quantity and quality of nutrient components of kenaf leaves.

Surface Chemical Groups of Flocs Are Key Factors for the Growth of Flocs in Sweep Coagulation: A Case Study of Surface Occupation by Humic Acid

Coagulation is one of the most common processes in water treatment. Charge neutralization and sweep flocculation are recognized as the primary coagulation mechanisms. However, in-depth understanding on floc growth, breakage, and regrowth is still unclear. In this study, the formation, breakage, and regrowth of alum flocs with humic acid (HA) added either before coagulant addition or during the floc breakage stage were investigated. The floc size continuously decreased with the increase in floc breakage events, and eventually, to a stable value. The floc growth was not affected by the addition of HA before coagulant addition. However, it was prevented as HA was added during the breakage stage, and the prevention extent increased with HA dose. Similar results were also found for natural organic matter (NOM) from real surface water. These results suggested that HA/NOM can cover the active site on the floc surface, and the coverage differed for fresh flocs (newly precipitated) and old flocs (after breakage), which, respectively, represent the case in conventional coagulation and sludge recirculation. Based on these findings, the illustration of floc growth, breakage, and regrowth processes was put forward. We concluded that the charge neutralization and sweep flocculation mechanisms only explained the possibility of flocs approaching each other; whether flocs can connect to each other depends on the activated functional groups on the floc surface. The results in this study revealed the underlying mechanism of “collision effectiveness” in coagulation, complementing the existing understanding of the coagulation process.

Response of Red Chili (Capsicum anuuum L.) to Humic Acid Application in Dryland

Red chili cultivation in dry land in an effort to increase production and productivity is constrained by the limited availability of water. The application of humic acid increases the ability of soils to retain restricted water and enhances plant growth and yield. This study aimed to investigate the response of red chili grown in dry land to the application of humic acid. Research place at the Teaching and Research Farm, Faculty of Agriculture, Jambi University. A Randomized Block Design with 5 replications was used in this study. The treated humic acid dose is 0 ton/ha, 2.5 ton/ha, 5 ton/ha, 7.5 ton/ha, and 10 ton/ha. Red chili gave a positive response to the application of humic acid by increasing plant height, number of branches, fruit number, and fruit weight. The dose of humic acid that gave the highest yield of 6.6 ton/ha was 5 ton/ha. This study was only able to provide a yield of 44.06% when compared to the potential yield of red chili.

Foliar application of humic acid at heading improves physiological and agronomic characteristics of durum wheat (Triticum durum L.)

BackgroundCrop production with lesser use of chemicals have attracted significant attention due to better quality. Organic manures are commonly used to fulfill the nutrient requirements of crop plants in organic farming. Humic acid could help to further improve the growth and productivity of crop plants in organic farming. Therefore, this study assessed the role of humic acid in improving physiological and agronomic attributes of durum wheat (Triticum durum L.). MethodsFive different doses of humic acid, i.e., 0 (H0), 1.5 (H1), 2.5 (H2), 3.5 (H3) and 4.5 (H4) L/ha were applied at two different phenological stages, i.e., stem elongation (SE) and heading (H) of wheat in organic field. Durum wheat variety ‘Burgos’ widely cultivated in Turkey was used as plant material. Data relating to chlorophyll index (CC), flag sheet area (FSA), proline content (PC), plant height (PH), protein ratio (PR), and grain yield (GY) were recorded. ResultsDifferent physiological and agronomic traits were significantly affected by humic acid doses and growth stages. Overall, the lowest values of CC, FSA, PC, PH and GY were noted for H0, whereas H4 resulted in the highest values of these traits. Grain yield was 3882.82 kg ha−1 in H0 and increased to 4988.14 kg ha−1 (28 %) in H4 dose of humic acid. The GY was decreased, whereas PC and PR increased in the second year of the experiment due to warmer and drier weather conditions. The highest PC values were noted in H0, and the PC values decreased with the increase in humic acid doses. ConclusionHumic acid application created favorable growing environments for plant growth. Overall, the application of H4 dose at heading stage resulted in the highest yield and related traits. Therefore, it is recommended that application of 4.5 L/ha humic acid at heading stage could be used to improve durum wheat yield under organic farming.

Humic Acid Improves Plant Yield, Antimicrobial Activity and Essential Oil Composition of Oregano (Origanum vulgare L. subsp. hirtum (Link.) Ietswaart)

The effects of humic acid on plant yield, essential oil content, the composition of essential oil and the antimicrobial activity of Origanum vulgare L. subsp. hirtum (Link.) (cv. Tinmaz) cultivated in 2017 and 2018 under Eskisehir ecological conditions were evaluated. Three humic acid (HA) doses in response to 50.0 L ha−1 (HA 50), 30.0 L ha−1 (HA 30) and 0.0 L ha−1 (HA 0, as control) were applied to soil at the vegetative stage and beginning of the blooming stage of the plant throughout each harvest in both years. Essential oil composition was determined using GC-FID/GC-MS. The antibacterial and antifungal activity were determined by the well-diffusion method. Fresh herb yield, dry herb yield and dry leaf yield were highest at HA 50 both years, although essential oil content increased in 2017 at both HA 50 and HA 30, but was greatest at HA 50 in the second year. The essential oil content differences between the control dose and 50.0 L HA ha−1 were 0.46% and 0.42% in 2017 and 2018, respectively. The antimicrobial activity of the essential oil samples against two bacteria species (Enterococcus faecalis and Staphylococcus aureus) and two yeast species (Candida albicans and Candida parapisilosis) was generally higher than that of the control drugs, and the activity increased with increasing HA doses. Analysis of the essential oil components showed that the carvacrol and γ-Terpinene ratios generally increased as the HA doses increased to 50.0 L HA ha−1. Soil HA applications could be recommended for higher quality, plant yield and antimicrobial activity of Origanum vulgare L. subsp. hirtum.

INFLUENCE OF HUMIC ACID ON VEGETATIVE AND REPRODUCTIVE ATTRIBUTES OF AFRICAN MARIGOLD (Tagetes erecta L.)

The study entitled ‘influence of humic acid on vegetative and reproductive attributes of African marigold (Tagetes erecta L.)’ was studied at Agricultural Research Station Swabi during 2017. The main aim of this study was to find out the adequate dose of humic acid that can enhance vegetative and reproductive qualities of marigold. Randomized Complete Block Design (RCBD) was used with three replications. Four different concentrations (0, 1000ppm, 2000ppm, 3000ppm) of humic acid were sprayed during vegetative and reproductive stages of marigold plants. Humic acid was sprayed twice, 1st spray before reproductive stage and 2nd spray after the bud formation. The effect of humic acid on marigold was evaluated for plant height, number of leaves plant-1, stem diameter, blooms plant-1, blossom diameter, and blossom fresh and dry weight. Provision of humic acid at 1000ppm, 2000ppm and 3000ppm concentration ranges resulted in linear increase in leaves of a plant, stem diameter, plant height, blooms plant-1, blossom diameter, fresh and dry weight of blossom. But plants sprayed with 2000 ppm humic acid were effective for most of the parameters that can increase profit in marigold flowers business.

The potential of organomineral amendments in increasing the adsorption of lead (Pb) and cadmium (Cd) in a sandy loam soil

Sandy loam soils contain low organic carbon and have low ion adsorption capacity. Under certain conditions, the soils contain heavy metals that are harmful to plants. Soil amendments such as biosilica and humic acid from natural sources are expected to increase the soil adsorption capacity to heavy metals. A simulation experiment consisting of two factors was conducted to explore the effectiveness of humic and biosilica, as soil amendments, in adsorbing heavy metals from soils. The first factor was biosilica dose composing 0 t ha<sup>-1</sup> (S0), 0.5 t ha<sup>-1 </sup>(S1), 1 t ha<sup>-1 </sup>(S2), and 1.5 t ha<sup>-1 </sup>(S3). The second factor was the humic acid dose composing 0 kg ha<sup>-1</sup> (H0), 20 kg ha<sup>-1</sup> (H1), 40 kg ha<sup>-1</sup> (H2), and 60 kg ha<sup>-1</sup> (H3). The humic acid and biosilica were applied to soil contaminated with Pb and Cd. The results showed that the combination of 0.5 t biosilica ha<sup>-1</sup> (S1) and 20 kg humic acid ha<sup>-1</sup> (H1) significantly increased soil pH, organic C content, cation exchange capacity, and reduced the availability of Pb and Cd at 90 days after treatment. The Pb and Cd contents in plant tissue decreased from roots to grains. Humic acid treatment was more effective in absorbing Pb of 86.89-90.49% and Cd of 71.47-76.33% than other treatments.

The effect of humic acid on rapeseed (Brassica napus L.) plant growth, heavy metal uptake, phytoremediation parameters (BCF, TF and TI), and antioxidant activity in heavy metal polluted soil

The aim of this study was to investigate the effects of humic acid (HA) applications on rapeseed (Brassica napus L.) growth, heavy metal uptake, bioconcentration factor (BCF), translocation factor (TF), tolerance index (TI), catalase (CAT), ascorbate peroxidase (APX) enzyme activities and hydrogen peroxide (H2O2) content in polluted soil with lead (Pb), chromium (Cr), cadmium (Cd), and zinc (Zn). Three doses of HA (Control, HA1:500 mg kg-1, HA2:1000 mg kg-1, HA3:2000 mg kg-1) were applied in pots. HA1, HA2, and HA3 applications increased plant growth parameters compared to polluted soil. Compared to the control, HA applications in polluted soil increased the Pb, Cr, Cd, and Zn concentrations in the plant. However, HA applications in polluted soil significantly decreased the heavy metal content in roots and shoots of the plant compared to polluted soil. BCF in both roots and shoots of the plants were greater than 1 for Pb, Cr, Cd, and Zn. However, specifically HA2 application decreased the shoot and root BCF values in polluted soil. TF was smaller than 1 in Pb, Cr, Cd, and Zn in polluted soil. On the other hand, HA applications for Cd increased TF values. Shoot TI decreased 17.37 %, and root TI decreased 9.09% in polluted soil. CAT and APX enzyme activities and H2O2 increased significantly in polluted soil. However, HA applications decreased CAT and APX enzyme activities and H2O2 content in rapeseed. It is concluded that HA application in Pb, Cr, Cd, and Zn polluted soil has a remedial effect on the development of rapeseed by reducing heavy metal content and oxidative stress.

The Effect of Humic Acid and Nitrogen Fertilization on Nutrient Content of Lettuce

Bu araştırmada, humik asit ve azotlu gübrelemenin iki farklı marul bitkisinin besin element içerikleri üzerine etkisi incelenmiştir. Bu amaçla iki sıvı humik asidin 0-400-800-1200 mg kg-1 dozları ile üre ve amonyum nitrat gübresi uygulanmıştır. Çalışma sonuçlarına göre, Model marul çeşidinde amonyum nitrat gübre uygulaması ile humik asidin 800 mg kg-1 dozundan en yüksek yaş ve kuru ağırlık elde edilirken; Carmesi marul çeşidinde üre ve amonyum nitrat gübresi ile humik asidin 800 ve 400 mg kg-1 dozundan elde edilmiştir. Bitkinin K içeriğinin 800 mg kg-1, Fe içeriği ise 800 ile 1200 mg kg-1 humik asit dozlarına kadar artmıştır. Bitkinin toplam N ve nitrat ile Ca, Mn, Zn ve Cu içeriklerinin dozla birlikte genellikle düzenli bir şekilde arttığı; Mg içeriğinin düzenli bir şekilde azaldığı tespit edilmiştir.

Influence of Humic Acid and Vermicompost on Vegetative and Flowering Performances of African Marigold cv. Seracole in Indo-Gangetic Plains of West Bengal

The present investigation was performed in Horticultural Research Station, Mondouri, Bidhan Chandra Krishi Viswavidyalaya, Nadia, West Bengal during 2017 to 2018 to assess the best dose of humic acid and vermicompost combination for African marigold. The experiment was designed in Randomised Block Design (RBD) with three replications. There were four concentrations of humic acid extracts (0.5 g/l, 1.0 g/l, 1.5 g/l and 2 g/l) applied as a foliar spray in combination with basal doses of vermicompost (1 kg/m2 and 2 kg/m2). All the parameters showed significant differences regarding vegetative, flowering as well as quality parameters. The results indicated that foliar spray with 1.5 g/l of humic acid extract along with 2 kg/m2 vermicompost significantly increased plant height (54.54 cm), number of primary branches (7.21), flower diameter (7.44 cm), fresh weight & dry weight of flower (9.06 g & 1.2 g respectively), number of flowers per plant (84.16), yield per hectare (47.01 tons/ha) as well as the quality parameters. So, among the nine treatments, T8 (Humic acid 1.5 g/l + 2 kg vermicompost/m2) was the best combination for improving plant growth, yield and quality of African marigold in the Indo-Gangetic plains of West Bengal.

Evaluation of Antioxidant Activity of Garden Thyme (Thymus vulgaris L.) Affected by Humic Acid Under Urmia-Iran Condition

The trial aimed to study the effects of different levels of humic acid on the antioxidant activity of garden thyme. The study was conducted at the experimental fields of the Agronomy Department, Faculty of Agriculture, Urmia University, West Azerbaijan, Iran, and used randomized complete block design with four replications. Three different humic acid doses; 200 kg ha−1, 400 kg ha−1 and 600 kg ha−1, and control with no humic acid were the treatments. Total phenolic content, total flavonoid content, DPPH (1,1-diphenyl 2-picryl hydroxyl) radical scavenging activity, nitric oxide radical scavenging activity, and chain-breaking activity were determined. According to the results, the effect of different levels of humic acid in the first harvest on total flavonoid content and nitric oxide radical scavenging was significant whereas, in the second harvest, total phenols content, total flavonoids content, DPPH radical scavenging activity, and chain-breaking activity were significant. The maximum total phenolic content, and nitric oxide radical scavenging activity were obtained in the control treatment. The highest total flavonoid content, DPPH radical scavenging activity, and chain-breaking activity were obtained in the application of 400 kg ha−1 and 600 kg ha−1 humic acid.

Pengaruh Kombinasi Silika dan Asam Humat terhadap Ketersediaan Nitrogen dan Pertumbuhan Tanaman Padi pada Tanah Berpasir

Sandy soils have high macropores and low nutrient availability. This condition is caused by the soil matrix which has no negative charge, so that nutrients are easily lost due to washing. Nitrogen loss has been reported to reduce rice production by 6.10%. The research aims to examine the application of humic acid and silica to increase the availability of nitrogen nutrients. Humic acid from compost and silica from rice husk is expected to increase the negative charge of the soil so that can adsorbnutrient ions such as nitrogen. The research was carried out from March to September 2021 in the greenhouse and laboratory of the Faculty of Agriculture, National Development University "Veteran" East Java. The research was structured using a factorial Completely Randomized Design (CRD). The first factor is silica dose with a level of 0 ton/ha, 0.5 ton/ha, 1 ton/ha, and 1.5 ton/ha. The second factor is the dose of humic acid with a level of 0 kg/ha, 20 kg/ha, 40 kg/ha, and 60 kg/ha. Observation parameters include the availability of N in the soil, the growth of rice plants which include plant length and the number of tillers. The results showed that the combination of humic acid and silica didn't significantly affect plant length and number of tillers, but had a significant effect on nitrogen availability. The best dose of the combination of silica with humic acid on nitrogen availability in sandy soils is S2H3 (Silica 1 ton/ha with humic acid 60 kg/ha).

Humik Asit Uygulamalarının Zambak Bitkisinin Gelişimi, Bitkideki Fenolojik ve Pomolojik Gözlemler Üzerine Etkisi

In this study, a pot study was carried out to reveal the effects of direct and foliar applications of humic acid to the growing medium in addition to basic fertilization on the development and plant quality characteristics of lily plants grown in peat + perlite medium. The experiment was carried out in an unheated greenhouse during the summer, in a greenhouse environment with a shade net on it. In the experiment, in addition to the control, the humic acid doses were 3.5 lt/da from soil, 7.5 lt/da from soil, 1.75 lt/da from leaf, 3.75 lt/da from leaf and soil + 3.5 lt/da from leaf + 1, It was applied 3 times as 75 lt/da. In the pot experiment established in three replications according to the randomized plots trial design, 10 lily bulbs were planted in each pot and humic acid applications were made at two-week intervals following plant emergence. In order to see the effect of the applications when the plant is harvested, the length of the flower stem (mm), the thickness of the flower stem (mm), the fresh weight of the branch (mm), the number of buds (pieces), the bud length (cm), the number of leaves (pieces), Full bloom stem (mm) and vase life (days) were examined. As the doses of humic acid increased, the vegetative weight of the lily plant increased, while the effect of the applications on the investigated properties was different. With the mineral elements, hormones and plant growth regulators in humic acid, it has the feature of promoting the increase of biomass in the plant.