The role of humic acids in plant nutrition and soil amelioration
12 min read
How humates affect plants and protect the soil
Humates are natural, high-molecular, and environmentally safe growth regulators for plants. They are non-toxic, do not cause mutations, have no embryological activity, and leave no residues in produce, as they are rapidly incorporated into metabolism. Humic substances function simultaneously as fertilizer and as growth stimulants.
These preparations activate energy metabolism, improve cell membrane permeability for nutrients, and stimulate enzymatic systems. This increases the photosynthetic capacity of leaves and enhances protein synthesis. As a result, the general resistance of plants to extreme environmental conditions is improved.
The sorption capacity of humic acids allows for the remediation of contaminated soil. They convert heavy metals into insoluble compounds, stopping their accumulation in plants.
The binding mechanism depends on the specific element. Calcium ions form salt-like humates with a typical ionic bond of carboxyl groups. Upon contact with zinc, hydrogen atoms of the carboxyl groups are substituted, and phenolic hydroxyls react partially. Reactions with copper involve both carboxyl and phenolic hydroxyls.
In all cases, humic acids precipitate in the form of insoluble or sparingly soluble metal salts. Additionally, humates improve soil structure. In light soils, they ensure particle aggregation, while in heavy soils, they prevent the formation of crusts and cracks, improving aeration and water-holding capacity.
Humic substances also reduce the toxicity of pesticides through adsorption and immobilization processes. Plants absorb herbicides in the form of bound, safe complexes. At the same time, the activity of enzymes in the soil — urease, phosphatase, and malathion esterase, which are responsible for pesticide degradation — is increased.
Practical application of humic preparations
Free humic acids are water-insoluble and unavailable to plants. Only their salts of monovalent alkali metals and ammonium (sodium, potassium, and ammonium humates) possess physiological activity.
In agriculture, humates are used to increase yield, accelerate seed germination, and stimulate root growth. The preparations improve the survival rate of transplants during planting and activate the nitrate reductase enzyme. This increases plant resistance to diseases, frost, and drought, while reducing the nitrate and pesticide content in produce.
The most convenient form for work is a liquid ballast-free preparation with a concentration of 5–10%. Sodium and potassium humates are produced by saturating raw materials with caustic soda or potash, respectively. Ammonium humate is obtained by treating raw materials with aqueous ammonia.
| Direction of humate use | Recommended dilution ratio for 5% solution |
|---|---|
| Irrigation | 1:1000 |
| Seed treatment | 1:500 |
| Treatment of tubers and grain crop seed | 1:250 |
To restore soil fertility and for plant nutrition, the complex fertilizer "Agrovitkor" is also used. Its composition includes peat, poultry manure, natural soil, and patented bio-components. The preparation is applied directly to the soil and exceeds traditional organic and mineral top dressing in effectiveness.
- Application rate of "Agrovitkor" — 3–6 kg per 100 m²
- Consumption of "Agrovitkor" instead of 1–1.5 t of manure — 10–15 kg
- Effectiveness higher than mineral fertilizer — by 3–5 times
- Effectiveness higher than organic fertilizer — by several times
- Number of sprayings per growing season — 2–4 times
Regulations for dry application and liquid top dressing
Correct dosage of humic fertilizers and compliance with their application regulations determine the final crop yield. When applied dry, the preparations act as soil amendments, improving soil structure, whereas liquid top dressing acts directly on the development of the root system. To achieve maximum effect, it is important to strictly correlate application rates with the plant's growing season phases. Dry application requires mandatory contact with moist soil at the depth of the roots.
The application of humic fertilizers for the conservation and reproduction of soil fertility in the amount of 3–6 kg/100 m² must be carried out exclusively with mandatory incorporation.
- Rate of broadcast soil application — 2.5–6.0 kg/100 m²
- Humate content in the preparation Humate+7 — 37%
- Solubility of Lignohumate in water — 100%
- Concentration of active ingredient in Humate-80 — no less than 80%
| Application / Crop | Application rate | Application method |
|---|---|---|
| Main soil application | 2.5–6.0 kg / 100 m² | With subsequent incorporation |
| Restoration of soil fertility | 3–6 kg / 100 m² | With mandatory incorporation |
| Sowing of vegetable crops in holes | 10–15 g per hole | During sowing |
| Sowing of vegetable crops in rows | 25–50 g per linear meter | During sowing |
| Planting of berry crops | 0.2–0.3 kg per planting pit | During planting |
| Planting of fruit crops | 0.5–0.7 kg per planting pit | During planting |
To prepare a liquid top dressing, dilute 150–200 g of dry fertilizer in 8–10 l of water and let it stand for 2–3 hours. This solution is used for root applications on plants during the growing season in accordance with the following application rates.
| Crop | Working solution rate | Application frequency and timing |
|---|---|---|
| Vegetable crops | 0.5–0.75 l per plant | 3–5 times per season |
| Berry crops | 3–5 l per bush | 3.5 times during the May-June period |
| Fruit crops | 10–20 l per tree | 3–4 times during the May-June period |
Specifics of using ready-to-use formulations
The use of ready-to-use industrial products allows for precise dosing of active ingredients and microelements. Modern organo-mineral complexes are adapted for specific technological tasks: from seed treatment to autumn preparation of perennial plantations for winter. When working with specialized compositions, it is important to follow the rules for preparing stock and working solutions. Errors in concentrations can lead to chemical burns or reduced effectiveness of treatments.
The product Gumat+7 is a complex organo-mineral fertilizer with a high content of active ingredients. Its formula is designed to simultaneously saturate plants with humic acids and key microelements. Systematic use of the product improves plant metabolism and increases their overall disease resistance. Application rates depend on the development stage of the crop and the method of application.
| Purpose / Crop | Dosage | Application technology |
|---|---|---|
| Seed soaking | 0.5 g per 1 l of water | Until seed germination begins |
| Root top dressing (fruit and berry) | 20–40 g per tree (bush) | Followed by abundant irrigation |
| Root top dressing (vegetables and strawberry) | 6–8 g per plant | Followed by abundant irrigation |
| Foliar top dressing | 3–4 g per 10 l of water | Spraying: 2 l of working solution per 1 m² |
| Autumn irrigation (fruit and berry) | 6–8 g per 10 l of water | For successful wintering of plantations |
| Irrigation of houseplants | — | 3–4 times during the active growth period at intervals of 10–15 days |
The fertilizer Gumi-30 is produced in the form of a 30% aqueous paste, intended primarily for private household plots. It accelerates fruit ripening and noticeably increases overall plant productivity due to a balanced composition of macro- and microelements. The use of the product is based on a two-stage scheme with preliminary dilution of the concentrate. The liquid form ensures rapid penetration of active ingredients into plant tissues.
| Operation | Stock solution/water ratio | Rate and regulations |
|---|---|---|
| Spring and autumn enrichment of soil or compost | 15 ml of working solution per 10 l of water | Per 1 m² of soil or compost |
| Pre-sowing seed soaking | 2 drops of stock solution per 100 ml of water | Per 100 g of seed to increase emergence |
| Rooting of transplants and cuttings | 20 drops of stock solution per 1 l of water | Soaking for 12–24 hours |
| Pre-planting treatment of potato tubers | 65 ml of stock solution per 1 l of water | Dipping 10 kg of tubers before planting |
| Irrigation of garden plants | 15 ml of stock solution per 10 l of water | Every 2 weeks, rate per 2 m² |
| Spraying of garden plants | 15 ml of stock solution per 10 l of water | Every 2 weeks, rate per 100 m² |
| Irrigation and spraying of houseplants | 4 drops of stock solution per 200 ml of water | Every 2 weeks |
The product Gumat-80 contains an increased concentration of active compounds and is used for growth stimulation at all stages of the growing season. It is used for seed treatment, accelerating the establishment of transplants, and regular irrigation. The two-stage dilution scheme allows obtaining a stable working solution without precipitation. The exposure time during seed soaking varies significantly depending on the biological characteristics of the crop.
- Prepare the concentrate: completely dissolve 10 g of the product (1 tablet) in 10 l of water.
- Prepare the working solution: dilute 1 l of the obtained concentrate in 9 l of clean water.
| Crop or planting material | Soaking time | Treatment conditions |
|---|---|---|
| Cabbage seeds | 48 hours | In diluted working solution |
| Cucumber seeds | 24 hours | In diluted working solution |
| Tomato seeds | 72 hours | In diluted working solution |
| Flower and ornamental plant seeds | 1 day (24 hours) | At room temperature |
| Cuttings | 1 day (24 hours) | Immersion in solution to 1/3 of their length |
- Irrigation of plants during the growing season is carried out every 10–12 days (flowers — once every 7 days) with a working solution rate of 4–5 l/m² or per one bush.
- Treatment of fruit trees and shrubs is performed 4 times per season: during the period of flower bud formation, after flowering, at the beginning of fruit set drop, and during fruit growth.
The liquid product Gumisol activates the internal resources of plants, stimulating the processes of root formation, flowering, and fruiting. It also strengthens the natural immunity of crops to pathogens and environmental stress factors. Lignohumate, produced from plant raw materials, is characterized by complete solubility and compatibility with plant protection products in tank mixtures. Its composition is optimized for the rapid overcoming of physiological stress in plants.
The positive effect of Lignohumate application increases significantly under stress conditions for plants: at low temperatures, moisture deficiency or excess, as well as on saline soils.
Application of liquid humic preparations: Lignohumate, Oxyhumate, and Hydrohumate
Liquid humic preparations act quickly and precisely, which is why they are most effective for pre-sowing treatment and top dressing during critical stages of plant development. Lignohumate activates seed germination and transplant establishment, improving the development of the root system. Specific concentrations and exposure times are provided for each crop type and growing condition.
When preparing cabbage seed, strictly follow the timing regulations: they should be kept in the Lignohumate solution for no more than 12 hours. For seed of other open-field crops, the soaking time is 36 hours, and for greenhouse crops and nursery plants — 24 hours.
The application schemes for Lignohumate on various crops are structured by solution concentration and application method. For greenhouses, the dosage for irrigation is halved compared to open field conditions. Below are the precise parameters for treating plants at all stages of growth.
| Object of treatment | Application method | Concentration of preparation | Application regulations |
|---|---|---|---|
| Vegetable seed (greenhouse) | Soaking before sowing | 3 drops per 100 ml of water | Exposure 24 h, seed-to-solution volume ratio 1:3 |
| Vegetable seed (open field) | Soaking before sowing | 3 drops per 100 ml of water | Exposure 36 h, seed-to-solution volume ratio 1:3 |
| Cabbage seed | Soaking before sowing | 3 drops per 100 ml of water | Exposure 12 h, seed-to-solution volume ratio 1:3 |
| Nursery plants | Soaking of root system | 3 drops per 100 ml of water | Exposure 24 h |
| Transplants | Spraying of vegetative plants | 3 drops per 100 ml of water | At the 3–4 true leaf stage, 12 h before pricking out or planting |
| Open field plants | Spraying of vegetative plants | 3 drops per 100 ml of water | During the growing season |
| Greenhouse plants | Root irrigation | 10 ml per 20 l of water | 3-fold irrigation with a 15-day interval (the first immediately after planting), rate 5 l/m² |
| Houseplants | Root irrigation | 6 drops per 1 l of water | Irrigation frequency — once every 3 months |
The technology for treating potatoes with Lignohumate includes both pre-planting tuber preparation and subsequent foliar treatments of vegetative plants. This provides comprehensive support for the crop at the start and during the harvest formation period. Following the sequence of stages allows for the full potential of the preparation to be realized.
- Immersion of tubers in the preparation solution (40 ml per 1 l of water) before planting.
- First spraying of vegetative plantings when plants reach a height of 8–12 cm.
- Second spraying of vegetative plantings at the budding stage.
Oxy- and hydrohumate are alkaline solutions with an active ingredient content of 10%. These preparations are recommended for pre-sowing seed treatment and foliar top dressing of vegetative plants. They stimulate immunity and growth processes due to their rich organic composition.
- Humic acids — 45–60 %
- Fulvic acids — 20–25 %
- Low-molecular-weight organic acids — 15–18 %
- Polysaccharides — 5–8 %
- Storage temperature — from –5 to +30 °С
- Preparation shelf life — 5 years
Acetic, succinic, glutaric, glycolic, lactic, and levulinic acids have been identified in the low-molecular-weight organic acid composition of Oxy- and hydrohumate. The preparations are stable during storage, non-flammable, and non-toxic. Metal, polyethylene, and glass containers are suitable for their transport and storage.
Complex peat-humic fertilizers: Torgum and Effekton
Dry and complex peat-humic fertilizers combine the properties of mineral nutrition and organic soil conditioners. They gradually release nutrients into the soil solution, preventing rapid leaching. This allows for a reduction in the frequency of treatments and ensures a prolonged effect in the field.
Torgum is a complex granular fertilizer based on refined peat, which is tested for radionuclide and heavy metal content. Due to treatment with a potassium alkaline reagent, the mobility of the peat's active substances increases by more than 200 times. The fertilizer is enriched with nitrogen, phosphorus (2–4 %), and micronutrients, and also contains up to 4 % potassium humate salts.
The main advantage of Torgum is its long-lasting action. Nutrients are delivered to the soil gradually, without "burst" releases, and are not washed away by precipitation or groundwater. The fertilizer is applied in a single application, and its residual effect lasts for 3–4 years.
Torgum can be used at any phase of plant growth and development. Soaking seed in an aqueous extract of the fertilizer increases germination, vigor, and rate of emergence. Using the preparation when growing transplants and planting into the soil improves establishment and stimulates root growth. Incorporating Torgum during primary tillage accelerates plant development, shifts flowering to an earlier date, and increases yield by 20–30 %.
Effekton is a biologically active humified fertilizer obtained through the microbiological processing of peat. Beneficial microorganisms in its composition create centers of increased biochemical activity in the rhizosphere. As a result, the nitrogen and phosphorus supply to plants is improved, and the vitamins and stimulants produced by the microflora accelerate growth. The preparation is equally effective for seed treatment, as well as root and foliar top dressing.
For indoor floriculture and growing transplants, a concentrated organic-mineral fertilizer, Effekton-DTs, has been developed. Its physiologically active components make it possible to completely abandon the use of other organic fertilizers. The preparation contains macro- and micro-elements in an available form and has a neutral acidity level.
- Nitrogen (N) — 9.4 g/l
- Phosphorus (P) — 17.4 g/l
- Potassium (K) — 19.4 g/l
- Acidity (pH) — 6.5–7
In addition to essential nutrients, the composition of Effekton-DTs includes humic substances and biologically active components. The fertilizer is intended for the top dressing of flowers, ornamental crops, and transplants. It ensures stable root system development and abundant flowering.
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