Vegetative experiments with humates on vegetable and grain crops in northern Ukraine
In the northern regions of Ukraine, where agroclimatic factors often limit yield potential, innovative approaches to stimulating the growth of agricultural crops are of particular importance. One such tool is humic preparations—humates derived from natural organic sources. Vegetative experiments conducted using humates have demonstrated noticeable positive changes in the growth and development of both vegetable and grain crops.
The aim of the research was to determine the effectiveness of humate application at various stages of crop growth—from seed germination to yield formation. The experiments were conducted on typical chernozems and sod-podzolic soils in the Chernihiv and Sumy regions. To assess the impact, control and experimental plots were used with varying doses and methods of humate application (foliar treatment, watering, seed soaking).
In the case of tomatoes and cucumbers, an acceleration of seed germination by 2–3 days and an increase in plant biomass by 20–25% compared to the control were observed. For grain crops, particularly spring wheat and oats, improved tillering, increased spike length, and overall grain mass per unit area were noted. A reduction in plant disease susceptibility during the active growth phase was also recorded.
The obtained data indicate high biological activity of humates under the moderately continental climate of northern Ukraine. Their application can become an effective element of sustainable agriculture, especially in the context of reducing chemical environmental impact. Further research will allow for more detailed determination of optimal norms and methods of humate application in various soil-climatic zones.
Table 1. Vegetative experiments on gray forest sandy soil with wheat (average of three replicates)
| Experiment variants | Dose per vessel, mg | Nitrogen applied per vessel, g | Yield per vessel, g | Yield increase, % | Experiment error (t), % | Reliability coefficient (t) |
|---|---|---|---|---|---|---|
| Experiments 2019 | ||||||
| Control | - | 2.0 | 4.71 | - | - | - |
| Amino Energy | 10.0 | 0.338 | 4.31 | 135 | - | - |
| Mind | 10.0 | 0.290 | 4.63 | 115 | - | - |
| NPK (background) | 6.6 | 0.500 | 6.24 | 131 | - | - |
| Background + Mind | 6.6 + 10.0 | 0.790 | 6.24 | 212 | - | - |
| Experiments 2020 | ||||||
| Control | - | - | 4.16 | - | - | - |
| Mind | 10.0 | 0.25 | 8.21 | 97.1 | 4.0 | 12 |
| Adept | 10.0 | 0.25 | 10.29 | 265.0 | 2.14 | 33.9 |
| Amino Energy | - | - | 2.89 | - | - | - |
| Amino Energy | 9.3 | 0.25 | 9.43 | 256.2 | 3.93 | 17.9 |
| Superphosphate, equivalent to Adept | - | 0.62 | 3.66 | 26.6 | - | - |
| Experiments 2021 | ||||||
| Control | - | - | 5.56 | - | - | - |
| Amino Energy | 50.0 | 1.25 | 20.21 | 263.1 | 8.2 | 8.9 |
| NH4NO3, equivalent to Amino Energy | - | - | - | - | - | - |
| Ammonia water, equivalent to Amino Energy | - | - | - | - | - | - |
The experiments show that various forms of liquid humic fertilizers are effective, with yield increases reaching up to 265%. Notably, the yield increase from Adept (10.29 g) was lower than the sum of increases from Amino Energy and superphosphate (9.43 g + 3.66 g). This is likely due to partial interaction of humic acids with calcium in superphosphate, resulting in insoluble calcium humates that have a lesser impact on yield improvement.
In field conditions, humic fertilizers were tested on grain and vegetable crops. Experiments with wheat showed that applying 2 l/ha of Amino Energy resulted in a 15% yield increase. The best results were obtained on poor soils. The fertilizers also improved crop quality, increasing protein and sugar content. Application of Amino Energy to oats and corn for silage increased yields by 6.5–13.5 c/ha and 60–200 c/ha, respectively.
Application of Amino Energy to vegetable crops over several years also ensured significant yield increases. An example is the results of two-year experiments presented in Table 2.
Table 2. Effectiveness of Amino Energy and Adept on tomatoes (field experiments, sod-carbonate soil, Chernihiv region)
| Experiment variants | Fertilizers applied, l/ha | Nitrogen applied, kg/ha | 2019 | 2020 | ||||
|---|---|---|---|---|---|---|---|---|
| Yield, c/ha | Increase, c/ha | Increase, % | Yield, c/ha | Increase, c/ha | Increase, % | |||
| Control | - | - | 50.6 | - | - | 24.6 | - | - |
| Amino Energy, 0.1 ml per hole | 2 | 35.0 | 91.8 | 41.2 | 81 | 43.5 | 18.9 | 76 |
| Adept, 0.04 ml per hole | 0.9 | 12.8 | 93.5 | 42.9 | 84 | 66.0 | 41.4 | 168 |
| Superphosphate, 12 g per hole | 2.5 | - | 71.2 | 20.6 | 41 | 36.4 | 11.8 | 47 |
Note: t = 4%, m = 3%
Vegetative experiments on tomatoes also demonstrated high effectiveness of various forms of humic fertilizers (Table 3). The effectiveness of humic fertilizers on sandy soils without background and with full mineral fertilizer background varies. In the latter case, it is 2–3 times lower. However, the yield increase from applying humic fertilizers against the NPK background remains significant (32–47%), justifying their combined use with mineral fertilizers.
Table 3. Influence of various forms of humic fertilizers on tomatoes (vegetative experiments, gray forest sandy soil, 2021)
| Experiment variants | Fertilizer dose per vessel, ml | Nitrogen applied per vessel, g | Yield, g | Yield increase, g | Experiment error (t), % | Reliability coefficient (t) |
|---|---|---|---|---|---|---|
| Without background | ||||||
| Control | - | - | - | - | - | - |
| Amino Energy | 0.25 | 1.25 | 55.0 | 321.1 | 7.34 | 11.6 |
| Amino Energy (10% concentrate) | 0.35 | 0.42 | 376.1 | 332.5 | 9.62 | 10.4 |
| Potassium humate | 0.6 | - | 387.5 | 288.2 | 11.8 | 8.48 |
| Background — NPK (7.03 g per vessel) | ||||||
| Control | - | - | 369.4 | - | - | - |
| Amino Energy | 0.25 | 1.25 | 527.1 | 157.7 | 7.33 | 4.56 |
| Amino Energy (10% concentrate) | 0.35 | 0.42 | 487.4 | 118.0 | 7.71 | 2.11 |
| Potassium humate | 0.6 | - | 523.2 | 153.8 | 2.26 | 13.6 |
Liquid humic fertilizers (Amino Energy and potassium humate) were tested both as low-concentration solutions and, since 2019, as high-concentration solutions (5–10%). Concentrated liquid humic fertilizers were tested in vegetative and field conditions. The results of vegetative experiments are presented in Table 4.
Table 4. Influence of various forms of humic fertilizers on wheat yield (vegetative experiments)
| Experiment variants | Fertilizer dose per vessel, ml | Nitrogen applied per vessel, g | Yield, g | Yield increase, % | Experiment error (t), % | Reliability coefficient (t) |
|---|---|---|---|---|---|---|
| Gray forest sandy soil, 2019 | ||||||
| Control | - | - | 2.00 | - | - | - |
| Amino Energy 6% | 20.0 | 0.01 | 5.40 | 170 | - | - |
| Potassium humate 10% | 10.0 | 1.0 | 2.88 | 44 | - | - |
| Ammonia water 25% | 10.0 | - | 4.68 | 134 | - | - |
| Gray forest sandy soil, 2020 | ||||||
| Control | - | - | 2.83 | - | - | - |
| Amino Energy 10% | 10 | 0.02 | 4.28 | 51.2 | 4.6 | 7.2 |
| Dark gray forest soil, 2020 | ||||||
| Control | - | - | 9.61 | - | - | - |
| Amino Energy 10% | 10 | 0.02 | 11.29 | 17.4 | 13 | 1.3 |
| Amino Energy 8% | 10 | 0.25 | 11.84 | 23.2 | 13 | 1.4 |
The experiments show that liquid concentrated fertilizers are particularly effective on poor soils and deserve attention as inexpensive and easily applicable fertilizers. Field experiments, where liquid fertilizers were applied using irrigation systems, also confirmed their effectiveness (Table 5).
Table 5. Influence of liquid concentrated fertilizers on vegetable yield increase (average of replicates)
| Experiment variants | Fertilizers applied, l/ha | Active substance (humic acids, g/ha) | Nitrogen applied, kg/ha | Marketable yield, c/ha | Increase, c/ha | Increase, % | Experiment error (t), % | Reliability coefficient (t) |
|---|---|---|---|---|---|---|---|---|
| Potatoes | ||||||||
| Control | - | - | - | 96.3 | - | - | - | - |
| Amino Energy, 10% solution | 2 | 600 | 1.54 | 125.9 | 28.6 | 29.6 | 5.8 | 3.5 |
| Cabbage | ||||||||
| Control | - | - | - | 274.6 | - | - | - | - |
| Amino Energy, 5% solution | 1 | 150 | 0.23 | 296.9 | 22.3 | 8.1 | 6.5 | 1.22 |
| Potassium humate, 5% solution | 1 | 150 | - | 333.2 | 57.6 | 20.9 | 9.0 | 1.90 |
Numerous field experiments have proven the effectiveness of Amino Energy and potassium humate preparations applied in low concentrations (0.05–0.5%) for plant nutrition. The best results in open ground were achieved with 0.05% solutions: for cabbage (application during the seedling period, at planting, and twice after planting), the increase in marketable yield was 15–20%, for cucumbers—16–51%, and for tomatoes—10–30%.
In closed ground, two methods were tested over three years: seed soaking and plant spraying (Tables 6 and 7).
Table 6. Effectiveness of soaking cucumber seeds in Amino Energy (average of replicates, 2020)
| Experiment variants | Yield, kg/m² | Increase, kg/m² | Increase, % |
|---|---|---|---|
| Control (soaking in water) | 13.15 | - | - |
| Soaking in Amino Energy solutions, 0.05% | 15.5 | 2.4 | 17.8 |
| Soaking in Amino Energy solutions, 0.005% | 14.5 | 1.4 | 10.2 |
Table 7. Effectiveness of spraying cucumbers and tomatoes with humate solutions
| Experiment variants | Average yield, kg/m² | Increase, kg/m² | Increase, % | Experiment error (t), % | Reliability coefficient (t) |
|---|---|---|---|---|---|
| Cucumbers | |||||
| Control (spraying with water) | 24.4 | - | - | - | - |
| Spraying with potassium humate solutions, 0.05% | 28.5 | 4.1 | 16.8 | 0.65 | 6.32 |
| Spraying with potassium humate solutions, 0.005% | 27.9 | 3.5 | 10.2 | 1.1 | 3.18 |
| Tomatoes | |||||
| Control (spraying with water) | 25.55 | - | - | - | - |
| Spraying with Amino Energy solutions, 0.05% | 27.23 | 1.68 | 6.5 | 0.93 | 1.8 |
| Spraying with Amino Energy solutions, 0.005% | 29.16 | 3.61 | 14.12 | 2.35 | 1.6 |
The experiments showed that 0.5% concentration solutions inhibit plant growth. Soaking tomato seeds in humate solutions was less effective. Spraying cucumbers and tomatoes with weak humate solutions (0.05% and 0.005%) was more effective than seed soaking, ensuring a yield increase of 14–16%.
Spraying wheat
The influence of spraying wheat crops with Amino Energy on yield was studied. It was found that the best timing for spraying (at a dose of 300 l/ha of 0.5% solution) are the tillering and stem elongation phases. At higher concentrations (1%), the effect was lower. In 2021, trials of weak humate concentrations were conducted in both vegetative and field experiments on light gray soil. Spraying was performed in the tillering phase with Amino Energy solutions at a rate of 300 l/ha. The experimental data are presented in Table 8.
Table 8. Effectiveness of spraying wheat in the tillering phase with humate solutions of different concentrations (average of replicates)
| Experiment variants | Vegetative experiments | Field experiments |
|---|---|---|
| Control | 15.4 | - |
| Spraying with Amino Energy, 1% | 16.6 | 1.2 |
| Spraying with Amino Energy, 0.5% | 16.2 | 0.8 |
| Spraying with Amino Energy, 0.05% | 19.2 | 3.8 |
| Spraying with Amino Energy, 0.005% | 18.2 | 2.8 |
Note: "x" — experiment not conducted.
Both in field and vegetative experiments, the greatest yield increase corresponded to a concentration of 0.05%. The use of agricultural aviation and agrodrones creates broad opportunities for treating crops over large areas, and the low cost of fertilizers applied in low concentrations enhances the economic efficiency of this agricultural practice.
Conclusions
- Testing of various forms of humic fertilizers in northern Ukraine demonstrated their high agronomic effectiveness.
- Along with Adept and potassium humate, the liquid preparation Amino Energy also showed high effectiveness and deserves further research.
- The application of Amino Energy and potassium humate in low concentrations (0.05–0.5%) in open and closed ground conditions confirmed their suitability for the northern regions of Ukraine.