Effects of Humic Preparations Potassium Humate, Adept Agro.Bio, and Mind Agro.Bio on Coniferous Crops
Seed germination is characterized by complex biochemical processes involving enzymes. The higher the activity of the enzymatic apparatus of cells, the more intensive the transformation of stored substances, which accelerates seed germination, and the sprouts exhibit faster growth of both the aerial parts and the root system.
It is known from the works of several authors that ion-dispersed forms of humic preparations can be assimilated by plants and used to enhance oxidative-reductive enzymatic systems. Oxidative-reductive processes, as now established, play a leading role in metabolism.
Enhancement of oxidative metabolism can be achieved through the application of humates. Experiments conducted on sandy soils in the Chernihiv region showed that the use of humic fertilizers in growing pine in nurseries and forest plantations yields a positive effect.
However, this issue has not been fully explored. Therefore, we conducted a series of studies aimed at:
- Determining the effect of humic preparations on the biochemical processes of germinating pine seeds;
- Investigating the role of humates in specific components of oxidative-reductive enzymatic systems and determining their relative contribution to oxidative metabolism in pine at early developmental stages;
- Comparing the stimulatory effects of humic products and certain polyphenolic compounds on seed germination, sprout growth, and rooting of cuttings of various plants;
- Testing the feasibility of using a growth stimulator based on humate and thymohydroquinone in growing pine seedlings in northern Ukraine.
Research Methodology
The experiment studying the activating effect of humic preparations on biochemical processes in germinating seeds was conducted with Scots pine seeds as follows. Pine seeds were placed for germination in distilled water and in a solution of dialyzed potassium humate at a concentration of 0.001%.
In the germinating seeds, the dynamics dynamics of transformation of stored substances, primarily the carbohydrate complex, were determined every 48 hours by measuring the content of mono- and disaccharides, the activity of hydrolytic enzymes—amylase and sucrase. Additionally, the activity of respiratory enzymes—catalase and peroxidase, the amount of phosphorus soluble in 4% trichloroacetic acid, and ammonia nitrogen were measured. Prior to this, all the above indicators were determined in dry seeds to characterize their initial state.
The experiment began on June 11, 2015, and concluded on June 19, 2015.
Experiments to identify the leading enzymatic systems during seed germination and the effect of humic preparations on them were conducted with sprouted seeds and young pine sprouts.
To determine the role of individual enzymes, the method of inhibiting a specific component of oxidative-reductive systems was used, while simultaneously measuring the intensity of respiration using the gasometric method in a Warburg apparatus. During these experiments, it was assumed that if plant tissues are infiltrated with humic acid and a specific enzymatic system is inhibited simultaneously, it is possible to determine which component is enhanced under the influence of humic acid.
Based on the above theoretical concepts about the role of humic preparations in enhancing the enzymatic apparatus of the cell, we used resorcinol and hydrogen sulfide as inhibitors. Resorcinol is a specific inactivator of polyphenol oxidase, while hydrogen sulfide suppresses all other metal-containing oxidases. The latter inhibitor was used because, during the oxidation of polyphenols, the terminal oxidase is not always polyphenol oxidase. In this experiment, seeds were soaked in water until sprouting, then transferred to solutions of the specified inhibitors and humate, and after 20 hours, the intensity of respiration was measured.
Additionally, in another experiment, the needles of 3-week-old pine sprouts were infiltrated (vacuum pressure of 30 mmHg, exposure for 45 minutes) with water, humate, resorcinol, and hydrogen sulfide water, after which the intensity of respiration was measured in them. Humate was used in the form of potassium humate at a concentration of 0.001%, resorcinol at M:10, and hydrogen sulfide in trace amounts.
The sample weight of seeds and needles was 200 mg. The experiments were conducted in duplicate, but for greater reliability, these experiments were repeated several times.
To compare the stimulatory effect of humic preparations and certain polyphenolic compounds on seed germination, sprout growth, and rooting of cuttings of various plants, experiments were set up with pine, yellow acacia, Chinese rose, and sedum. In these experiments, potassium humate, Mind Extra, tannins, and thymohydroquinone were tested. Tannins were used at concentrations of 0.001% and 0.0001%, and thymohydroquinone at 0.00025% and 0.000025%. Mind Extra, a Ukrainian preparation, is a concentrated organic-synthetic fertilizer, soluble in water, containing: humic acid—15%, P₂O₅—1%, K₂O—3%. This preparation was tested at the same concentrations as potassium humate (0.001–0.005%).
In the experiments, pine and yellow acacia seeds were germinated in the specified solutions. Every 3 days, the sprouted and germinated seeds were counted. The resulting sprouts were then transplanted into solutions of the same substances, but distilled water and Knop’s nutrient mixture were used as the medium.
At the end of the experiment, the sizes of the aerial and root parts of the plants, the weight of the plants, and the intensity of respiration were measured.
In the experiment studying the effect of these substances on rooting, cuttings of Chinese rose and sedum were planted in the corresponding solutions, after which the appearance of the first roots and their length were recorded.
Field experiments were conducted in the Chernihiv region, in a forest enterprise located on loamy chernozem. In these experiments, the effect of potassium humate, Mind Extra, and thymohydroquinone on the quality of pine planting material was tested. The plot size was 0.05 hectares. The experiments were conducted in triplicate.
Experimental Results
The results of the experiments studying the effect of humic preparations on biochemical processes in germinating Scots pine seeds (Tables 1 and 2) show that at the beginning of pine seed germination, despite the rapid activation of the respiration process, there is an accumulation of monosaccharides, and only on the 7th day of germination does their content begin to decrease.
| Sample Collection Time | Monosaccharides | Disaccharides | P₂O₅ Soluble in 4% Trichloroacetic Acid | Ammonia Nitrogen | ||||
|---|---|---|---|---|---|---|---|---|
| Water | Potassium Humate | Water | Potassium Humate | Water | Potassium Humate | Water | Potassium Humate | |
| Dry Seeds — Control | 0.134 | 0.134 | 2.52 | 2.52 | 0.017 | 0.017 | 0.37 | 0.37 |
| After Germination: Day 3 | 0.54 | 0.64 | 2.94 | 2.68 | 0.015 | 0.015 | 1.00 | 1.35 |
| Day 5 | 1.76 | 1.38 | 0.83 | 1.78 | 0.045 | 0.049 | 0.63 | 0.85 |
| Day 7 | 0.92 | 1.10 | 1.50 | 0.69 | 0.033 | 0.040 | 1.88 | 1.88 |
| Day 9 | 4.24 | 4.84 | 5.26 | 4.43 | 0.033 | 0.050 | - | - |
The amount of disaccharides also increased in the first days of germination, but by the 5th day, their content decreased. This is explained by the fact that the transformation of disaccharides into monosaccharides under the influence of increasing invertase activity occurs faster than the transformation of starch into disaccharides under the influence of amylase.
| Sample Collection Time | Catalase (ml H₂O₂ per 1 g) | Peroxidase (mg Sona per 1 g) | Amylase (mg maltose per 100 mg) | Invertase (mg sucrose per 100 mg) | ||||
|---|---|---|---|---|---|---|---|---|
| Water | Potassium Humate | Water | Potassium Humate | Water | Potassium Humate | Water | Potassium Humate | |
| Dry Seeds — Control | 21.8 | 21.8 | 0.56 | 0.56 | 7.5 | 7.5 | 38.3 | 38.3 |
| After Germination: Day 3 | 111.0 | 120.0 | 0.79 | 0.58 | 12.6 | 16.2 | 50.2 | 67.5 |
| Day 5 | 157.4 | 144.2 | 1.20 | 1.38 | 15.4 | 19.3 | 173.9 | 177.6 |
| Day 7 | 173.2 | 173.7 | 3.20 | 4.30 | 20.0 | 13.4 | 203.5 | 183.7 |
| Day 9 | 45.2 | 53.3 | 3.30 | 3.30 | - | - | 33.7 | 33.7 |
Note: On the 9th day of germination, the sprouts turned green.
The emergence of pine seeds from dormancy was characterized by the activation of respiratory enzymes—catalase and peroxidase, as well as an increase in the amount of phosphorus soluble in trichloroacetic acid. This form of phosphorus, along with the activity of respiratory enzymes, is an indicator of the energy processes of cells.
The decrease in the activity of some enzymes at the end of the experiment—on the 9th day (Table 2)—is a completely natural phenomenon, as enzymes are present in small amounts in dormant seeds. During seed germination, their content increases, reaching a certain maximum, and then decreases again. This study also indicates that in germinating wheat seeds, the activity of almost all enzymes peaks on days 6–8, and in germinating sunflower seeds, on days 6–7.
Several researchers provide data on the activity of certain enzymes in germinating barley, corn, and bean seeds, as well as on the quantitative changes in various forms of carbohydrates. These were found to be analogous to our data.
Table 2 also shows that humates in this experiment contributed to an increase in the activity of amylase, invertase, and catalase, as well as an increase in the content of phosphorus soluble in 4% trichloroacetic acid compared to the control.
The positive effect of humic preparations on these indicators was observed from the first days of the experiment. However, the activity of peroxidase under the influence of humates surpassed the control only 6–8 days after seed soaking, i.e., when sprouts appeared and needle formation began. This effect of humic and fulvic acids on the activity of respiratory enzymes should be explained by the fact that in germinating pine seeds, peroxidase is not the leading enzyme in oxidative-reductive processes. Its significance increases during needle formation. It is possible that the leading oxidase at this stage of pine development is cytochrome oxidase, and this enzyme can be considered a universal oxidase of plant embryos.
Thus, comparing the effect of humic preparations (Potassium Humate, Mind Extra, Adept) on the content of sugars, phosphorus soluble in trichloroacetic acid, and the activity of respiratory enzymes, it can be said that they increase the energy potential of germinating pine seeds.
However, after these experiments, it remains unclear how humates enhance oxidative-reductive processes and which enzymes are leading at this stage of development. The results of the experiments presented in Table 3 partially answer these questions.
| Experimental Schemes | Seeds | Needles | ||
|---|---|---|---|---|
| O₂ Absorbed in 5 min (mm³) | % | O₂ Absorbed by 200 mg Sample (mm³) | % | |
| Water | 92.3 | 100.0 | 132.1 | 100.0 |
| Potassium Humate | 157.3 | 170.4 | 241.1 | 182.5 |
| Hydrogen Sulfide | 67.1 | 72.7 | 92.3 | 69.8 |
| Potassium Humate + H₂S | 117.4 | 127.0 | 111.1 | 84.9 |
| Resorcinol | 92.3 | 100.0 | 102.7 | 77.7 |
| Potassium Humate + Resorcinol | 157.0 | 170.4 | 157.3 | 119.0 |
These data show that in germinating seeds, polyphenol oxidase likely does not participate in oxidative processes, as treatment with resorcinol did not affect seed respiration. However, in the needles of 3-week-old sprouts, its role noticeably increases, as evidenced by the suppression of respiratory gas exchange by resorcinol by 23%. Despite this, potassium humate significantly enhances respiration in both germinating seeds and needles. When needles were infiltrated with potassium humate alone, respiration increased by 82.5%, whereas its use with an inhibitor suppressing polyphenol oxidase increased it by only 19%. This indicates that humic and fulvic acids enhance the phenolase oxidative system, but their effect on oxidative metabolism is not limited to the participation of polyphenolic groups. In germinating seeds, humic and fulvic acids increased oxygen absorption by 70%, despite the fact that polyphenol oxidase and peroxidase were not active in them.
From this, three assumptions can be made:
- The effect of humic preparations on oxidative metabolism is not limited to enhancing only the phenolase system, where the terminal oxidase is polyphenol oxidase.
- The polyphenolic groups of humates functioned as hydrogen donors for other intermediate acceptors, which allowed the activation of oxygen metabolism to occur without the participation of polyphenol oxidase.
- The activation of respiration processes under the influence of humic and fulvic acids is not due to their polyphenolic groups.
The participation of the polyphenolic groups of this acid as a substrate for polyphenol oxidase activity is evidenced by the fact that as the activity of polyphenol oxidase in needles increased, so did the activating effect of humic and fulvic acids on oxidative metabolism.
The second proof of the participation of polyphenolic groups in oxidative metabolism would be the analogy in the effect of pure polyphenolic preparations and potassium humate on oxidative metabolism and the associated stimulatory effects on seed germination and sprout growth.
To verify this, several experiments were conducted, yielding similar results. Table 4 presents data from one of them, dated August 28, 2014.
Table 4. Stimulatory Effect of Humic and Other Polyphenolic Compounds on Seed Germination of Woody Crops
| Experimental Scheme | Sprouted and Germinated Scots Pine Seeds, % | Sprouted and Germinated Yellow Acacia Seeds, % | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 08.30 | 09.02 | 09.05 | 08.30 | 09.02 | 09.05 | |||||||
| Relative to Seeds Planted for Germination | Relativeacing to Control | Relative to Seeds Planted for Germination | Relative to Control | Relative to Seeds Planted for Germination | Relative to Control | Relative to Seeds Planted for Germination | Relative to Control | Relative to Seeds Planted for Germination | Relative to Control | Relative to Seeds Planted for Germination | Relative to Control | |
| Distilled Water (Control) | 46 | 100 | 52 | 100 | 52 | 100 | 44 | 100 | 46 | 100 | 46 | 100 |
| Potassium Humate 0.005% | 48 | 104 | 68 | 131 | 68 | 131 | 50 | 114 | 62 | 135 | 62 | 135 |
| Potassium Humate 0.001% | 52 | 113 | 52 | 100 | 78 | 150 | 44 | 100 | 46 | 100 | 50 | 109 |
| Mind Extra 0.005% | 52 | 113 | 56 | 108 | 60 | 115 | 26 | 60 | 26 | 56 | 26 | 56 |
| Mind Extra 0.001% | 44 | 96 | 44 | 85 | 48 | 92 | 40 | 91 | 48 | 104 | 48 | 104 |
| Tannins 0.001% | 58 | 126 | 68 | 131 | 68 | 131 | 20 | 70 | 30 | 65 | 30 | 65 |
| Tannins 0.0001% | 58 | 126 | 66 | 127 | 70 | 135 | 42 | 95 | 50 | 109 | 50 | 109 |
| Thymohydroquinone 0.00025% | 48 | 104 | 48 | 92 | 48 | 92 | 28 | 64 | 34 | 74 | 34 | 74 |
| Thymohydroquinone 0.000025% | 46 | 100 | 46 | 90 | 50 | 96 | 44 | 100 | 46 | 100 | 46 | 100 |
Table 4 shows that the stimulatory effect of the substances tested in the experiment on seed germination varied both within the same species and across different species.
Pine responded to germination stimulation much more intensely than yellow acacia. The greatest effect on pine was achieved with potassium humate and tannins at both concentrations, as well as with Mind Extra at a concentration of 0.005%. On yellow acacia, a noticeable effect was achieved only with potassium humate at a concentration of 0.005%. Thymohydroquinone at the tested concentrations did not show a positive effect on the germination of seeds of both species.
Based on these experiments, it can be concluded that the stimulatory effect depends on the concentration of the tested substances and the characteristics of the crops.
This experiment was continued as follows.
The obtained 2-week-old pine and yellow acacia sprouts were transplanted into solutions of the studied stimulatory substances added to distilled water, as well as against the background of mineral nutrition.
The results for this part of the experiment are presented in Tables 5 and 6.
Table 5. Effect of Humic Preparations and Certain Polyphenolic Compounds on the Initial Growth Stage of Scots Pine Sprouts
| Experimental Scheme | As of 09.15.2014 (Transplanting Moment) | As of 10.15.2014 | ||
|---|---|---|---|---|
| Aerial Part Height, mm | Root System Length, mm | Aerial Part Height, mm | Root System Length, mm | |
| Seeds germinated in distilled water, sprouts transplanted to distilled water | 15 | 40 | 17.5 | 45±5.0 |
| Seeds germinated in 0.001% potassium humate, sprouts transplanted to 0.001% potassium humate | 20 | 65 | 25.0 | 75±5.0 |
| Seeds germinated in 0.001% Mind Extra, sprouts transplanted to 0.001% humate-rex | 20 | 52 | 25.0 | 70±1.0 |
| Seeds germinated in 0.0001% tannin, sprouts transplanted to 0.0001% tannins | 20 | 52 | 22.5 | 67±3.3 |
| Seeds germinated in 0.000025% thymohydroquinone, sprouts transplanted to 0.000025% thymohydroquinone | 16 | 60 | 21.5 | 77±5.7 |
| Seeds germinated in distilled water, sprouts transplanted to Knop’s mixture | 15 | 40 | 27.5 | 52.5±2.5 |
| Seeds germinated in 0.001% potassium humate, sprouts transplanted to Knop’s mixture + 0.001% potassium humate | 20 | 65 | 27.5 | 75±2.8 |
| Seeds germinated in 0.001% Mind Extra, sprouts transplanted to Knop’s mixture + 0.001% Mind Extra | 20 | 52 | 22.5 | 67.5±2.5 |
| Seeds germinated in 0.0001% tannin, sprouts transplanted to Knop’s mixture + 0.0001% tannins | 20 | 52 | 23.0 | 65±2.8 |
| Seeds germinated in 0.000025% thymohydroquinone, sprouts transplanted to Knop’s mixture + 0.000025% thymohydroquinone | 16 | 60 | 25.0 | 71±1.2 |
The data in Tables 5 and 6 show that the effect of humic preparations and polyphenolic compounds on pine and yellow acacia sprouts was fundamentally similar.
In pine sprouts, all the substances tested in the experiment had a positive effect on the growth of the root system and aerial parts, both when added to distilled water and in the full Knop’s mixture. Their positive effect was primarily on the growth of the root system.
Among the humic preparations added to distilled water, a greater effect was achieved with potassium humate. In yellow acacia sprouts, no effect was observed only with tannin.
Table 6. Effect of Humates and Other Polyphenolic Compounds on Yellow Acacia Sprouts
Transplanting Period (09.15.2014)| Aerial Part Height, mm | Root System Length, mm | Aerial Part Height, mm | Root System Length, mm | Number of Lateral Roots, pcs | Number of Compound Leaves, pcs | |
|---|---|---|---|---|---|---|
| Seeds germinated in distilled water, sprouts transplanted to distilled water | 19.4 | 36.2 | 31 | 43±3 | 1.2 | 2 |
| Seeds germinated in 0.005% potassium humate, sprouts transplanted to 0.001% potassium humate | 25.7 | 77.5 | 32 | 85±4.6 | 1.2 | 3 |
| Seeds germinated in 0.001% potassium humate, sprouts transplanted to 0.001% potassium humate | 19.4 | 60.2 | 40 | 73±3.3 | 5 | 3 |
| Seeds germinated in 0.001% Mind Extra, sprouts transplanted to 0.001% Mind Extra | 23.7 | 60.0 | 39 | 70±8.7 | 4 | 3 |
| Seeds germinated in 0.0001% tannin, sprouts transplanted to 0.0001% tannins | 18.4 | 38.8 | 20 | 50±0.0 | 0 | 3 |
| Seeds germinated in distilled water, sprouts transplanted to full Knop’s mixture | 19.4 | 36.2 | 57 | 65±4.4 | 3 | 4 |
| Seeds germinated in 0.005% potassium humate, sprouts transplanted to full Knop’s mixture + 0.001% potassium humate | 25.7 | 77.5 | 62 | 150±10.7 | 3 | 5 |
| Seeds germinated in 0.001% potassium humate, sprouts transplanted to full Knop’s mixture + 0.001% potassium humate | 19.4 | 60.2 | 70 | 190±9.8 | 8 | 5 |
| Seeds germinated in 0.001% Mind Extra, sprouts transplanted to full Knop’s mixture + 0.001% Mind Extra | 23.7 | 60.2 | 55 | 160±15 | 3 | 5 |
| Seeds germinated in 0.0001% tannin, sprouts transplanted to full Knop’s mixture + 0.0001% tannins | 18.4 | 38.8 | 30 | 50±5.7 | 3 | 4 |
The effect of these substances positively impacted not only the growth of the aerial parts and root system of woody crop sprouts but also the increase in the fresh weight of these plant organs, and thus the entire plant as a whole, as shown in Table 7, which presents data on the weighing of yellow acacia sprouts.
Data (Table 8) on the determination of respiration intensity in the leaves of yellow acacia sprouts and Scots pine needles grown under different variants of the described experiment showed that an increase in oxygen absorption was obtained only for those variants that showed an effect on sprout growth.
These data indicate an analogy between the effects of humic preparations and polyphenolic compounds. However, these experiments do not allow us to assert that the effect of humic and fulvic acids is solely related to the presence of polyphenolic groups in their molecules, as the effect of humic preparations is generally higher than that of polyphenols.
No studies were conducted to decipher this residual effect of humic and fulvic acids.
The results of experiments studying the effect of the above preparations on the rooting of cuttings showed that humic preparations also have a positive effect on flowering plants. They accelerate the appearance of roots on cuttings and increase their growth, as shown in the data in Table 9.
Table 7. Effect of Humic Substances on the Accumulation of Fresh Weight by Yellow Acacia Sprouts (Data as of 10.15.2014 from the Experiment of 08.28.2014)
| Experimental Scheme | Fresh Weight, mg | ||
|---|---|---|---|
| Plants | Aerial Part | Root System | |
| Seeds germinated in distilled water, sprouts transplanted to full Knop’s mixture | 185 | 140 | 45 |
| Seeds germinated in 0.005% potassium humate, sprouts transplanted to full Knop’s mixture + 0.001% potassium humate | 220 | 160 | 60 |
| Seeds germinated in 0.001% potassium humate, sprouts transplanted to full Knop’s mixture + 0.001% potassium humate | 291 | 201 | 90 |
| Seeds germinated in 0.001% Mind Extra, sprouts transplanted to full Knop’s mixture + 0.001% Mind Extra | 255 | 200 | 55 |
| Seeds germinated in 0.0001% tannin, sprouts transplanted to full Knop’s mixture + 0.0001% tannins | 150 | 110 | 40 |
Table 8. Effect of Humic Preparations and Other Polyphenolic Compounds on Oxygen Absorption by Yellow Acacia Leaves and Scots Pine Needles (Experiment Initiated on 08.28.2014, Data as of 10.15.2014)
| Experimental Variants | Pine Needles | Yellow Acacia Leaves | ||
|---|---|---|---|---|
| Oxygen Absorbed in 5 Minutes by 200 mg Sample, mm³ | % Relative to Control | Oxygen Absorbed in 5 Minutes by 200 mg Sample, mm³ | % Relative to Control | |
| Full Knop’s Mixture | 150.3 | 100 | 67.1 | 100 |
| Full Knop’s Mixture + Potassium Humate (0.001%) | 213.8 | 142.0 | 176.8 | 218.7 |
| Full Knop’s Mixture + Mind Extra (0.001%) | 250.6 | 166.7 | 122.4 | 182.4 |
| Full Knop’s Mixture + Tannins (0.0001%) | 183.7 | 122.2 | 55.6 | 82.9 |
| Full Knop’s Mixture + Thymohydroquinone (0.000025%) | 241.7 | 160.8 | — | — |
Note: Respiration intensity was determined by the amount of oxygen absorbed manometrically in a Warburg apparatus.
Field experiments studying the effect of potassium humate in combination with mineral fertilizers showed (Table 10) that potassium humate has a positive effect on the quality of pine seedlings both with nitrogen-phosphorus fertilization and without fertilization, increasing the yield of standard seedlings, enhancing the growth of the aerial part, and improving the fibrousness of the root system.
In this experiment, two fertilizations were carried out. In the first fertilization, mineral fertilizers were applied at a rate of 2.5 g per linear meter of the sowing strip with irrigation. In the second, the nitrogen rate was the same as in the first, while the superphosphate rate was tripled.
Irrigation with potassium humate was carried out at a concentration of 0.001%. Fertilizations were conducted on May 22 and June 17.
Table 9. Effect of Potassium Humate, Thymohydroquinone, and Tannin on Rooting of Chinese Rose and Sedum Cuttings
| Experimental Scheme | Sedum | Chinese Rose | ||
|---|---|---|---|---|
| Date of Root Appearance | Root Length as of 07.01.2014, mm | Date of Root Appearance | Root Length as of 08.08.2014, mm | |
| Water | 06.04 | 16±1 | 06.30 | 15±1 |
| Potassium Humate 0.001% | 06.03 | 31±4 | 06.25 | 82±18 |
| Thymohydroquinone 0.00025% | 06.03 | 41±6 | 06.30 | 65±14 |
| Tannins 0.001% | 06.03 | 40±4 | 06.30 | 58±15 |
In the field experiments of 2015, humate containing nitrogen—0.3% and P₂O₅—0.96% soluble in 0.5N H₂SO₄ per absolutely dry weight was tested as a source of humic and fulvic acids.
Table 10. Effect of Mineral and Humic Fertilizer Applications on the Quality of Pine Seedlings (Status as of 10.05.2014 from the Experiment Conducted in Chernihiv Region)
| Experimental Scheme | Percentage of Standard Seedlings | Aerial Part Height, mm | Root Collar Diameter, mm | Number of Lateral Roots at Depth, pcs | |
|---|---|---|---|---|---|
| 0–15 cm | 0–50 cm | ||||
| Irrigation with water, no fertilizers | 60 | 39±3.0 | 2.5 | 13 | 27 |
| Irrigation with water, mineral fertilizers applied (NP) | 75 | 76±5.0 | 3.0 | 21 | 43 |
| Irrigation with humic preparations, mineral fertilizers applied (NP) | 81 | 84±4.2 | 3.0 | 22 | 50 |
| Irrigation with humic preparations, no fertilizers | 67 | 69±4.5 | 2.7 | 17 | 34 |
Note: The percentage of standard seedlings was determined by the number of seedlings that formed an apical bud relative to the total number of seedlings per linear meter.
In addition to potassium humate, the experimental scheme included Mind Extra and thymohydroquinone. They were applied manually in furrows after sowing seeds in the following amounts per linear meter of the sowing strip: potassium humate—150 g, Mind Extra—50 g, thymohydroquinone—0.15 g. Humic preparations were standardized for their content of water-soluble humic and fulvic acids. Data characterizing the condition of pine seedlings from this experiment are presented in Table 11.
Table 11 shows that all tested preparations had a positive effect on the quality of pine seedlings. Moreover, in the initial growth period of seedlings, thymohydroquinone gave better results, but later the situation began to shift in favor of potassium humate. As a result, by the end of the vegetation period (on 09.25), the highest quality planting material and the highest percentage of standard seedlings were obtained with humate.
Table 11. Effect of Humic Fertilizers and Thymohydroquinone on the Yield and Quality of Scots Pine Planting Material
| Experimental Scheme | Status as of 06.04.2015 | Status as of 08.20.2015 | Status as of 09.25.2015 | |||||
|---|---|---|---|---|---|---|---|---|
| Aerial Part Height, cm | Root System Length, cm | Aerial Part Height, cm | Number of Lateral Roots, pcs | Aerial Part Height, cm | Number of Lateral Roots, pcs | Stem Diameter, mm | Percentage of Standard Seedlings | |
| Control | 3.2 | 13.5 | 6.0±0.35 | 23 | 7.8±0.27 | 23 | 2.4 | 65 |
| Potassium Humate | 3.2 | 15.0 | 7.5±0.38 | 28 | 9.9±0.27 | 29 | 2.6 | 80 |
| Mind Extra | 3.0 | 15.0 | 7.0±0.38 | 20 | 8.7±0.25 | 26 | 2.6 | 74 |
| Thymohydroquinone | 3.5 | 17.0 | 7.5±0.20 | 28 | 8.8±0.23 | 29 | 2.4 | 70 |
All this shows that the stimulatory effect of humic, fulvic acids, and some polyphenols may have practical significance and can be used to obtain high-quality pine planting material, as well as in the cultivation of ornamental crops.
Conclusions
Based on the obtained experimental data, the following brief conclusions can be drawn:
- Humic and fulvic acids increase the energy potential of germinating pine seeds.
- The stimulatory effect of humic preparations and certain polyphenolic compounds on the germination of woody crop seeds depends on the concentration of the tested solutions and the biological characteristics of the crops. Thus, potassium humate gave the best results on pine at a concentration of 0.001%, and on yellow acacia at a concentration of 0.005%.
- Potassium humate, Mind Extra, tannins, and thymohydroquinone, when added to distilled water and in the full Knop’s mixture, have a positive effect on the growth of the aerial part and, primarily, the root system of pine sprouts, as well as accelerate the appearance of roots on flowering plants.
- The application of potassium humate, Mind Extra, and thymohydroquinone to pine in the nursery improves the quality of seedlings. The best results among all tested preparations were achieved with humophos.
- Experiments with inhibition show that the positive effect of humic and fulvic acids on biochemical processes in plants is not solely due to the presence of polyphenolic groups in their molecules, although there is an analogy between the effects of humic preparations and polyphenolic compounds on plants.