The influence of modern humic preparations Agro.Bio on the formation of the yield and quality of tomatoes depending on soil and climatic conditions
Modern scientific research reveals the influence of mineral and organic fertilizers, as well as climatic and soil conditions, on the yield and quality of agricultural products.
Long-term research conducted by Agro.Bio specialists and staff at specialized research institutes has shown that humic fertilizers have varying effects on yield increases and quality under different soil and climatic conditions. For example, the effectiveness of humic fertilizers in the Central Steppe is lower than in Polesia and the Southern Steppe, which have different soil and climatic conditions. Therefore, it is of interest to determine the extent to which the effectiveness of humic fertilizers depends on these conditions. Therefore, the aim of the research was to determine the effectiveness of humic fertilizers on various soil types under similar and different weather conditions.
To this end, we conducted two-year vegetation experiments at the agricultural universities of Dnipro and Kherson on two types of soil: ordinary chernozem and chestnut soil .
Agrochemical characteristics of soils
- Ordinary chernozem: low-humus, medium loamy, with a humus content of 4 to 4.5% on loess. Humic acids predominate. The aqueous extract is neutral or slightly alkaline. Total nitrogen is 0.3-0.5%, total phosphorus 0.1-0.3%, and total potassium 1.5-2%.
- Chestnut soils contain 2.5-3% humus, dominated by humic acids. The aqueous extract is slightly alkaline. These soils contain 0.15-0.3% total nitrogen, 0.15-0.25% phosphorus, and 0.5-2% potassium.
Agrochemical analyses of these soils showed that the content of available nitrogen and phosphorus in chestnut soil was somewhat higher than in chernozem soil, while the content of available potassium was the opposite.
Experimental conditions
Experiments were conducted in 2024 and 2025 using Volgogradsky tomato varieties in pots each holding 10 kg of soil. Twenty seeds were sown in each pot. The experiments were repeated four times. After seedlings emerged, the pots were thinned, leaving one plant in each pot.
The innovative complex preparation Adept Agro.Bio was tested as a humic fertilizer (optimal application rate of 2 l/ha) with a hydrolyzable nitrogen content of 0.67% and available phosphorus of 0.96% per wet sample; the fertilizer pH was 7.2. Of the mineral fertilizers, granular superphosphate and ammonium nitrate were used in quantities equivalent to Adept Agro.Bio in nitrogen and phosphorus content.
The Adept Agro.Bio dosage per vessel was 50 g (equivalent) at 50% moisture content and was applied directly to the plant, mixed with 1 kg of soil. Watering was performed by weight to maintain soil moisture in the vessels at 60% of their full capacity.
Table 1. Temperature, relative humidity and precipitation for the growing season of 2024 and 2025.
| Months | Dnipropetrovsk region (2024) | Dnipropetrovsk region (2025) | Kherson region (2025) | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Temp., °C | Humidity, % | Precipitation, mm | Temp., °C | Humidity, % | Precipitation, mm | Temp., °C | Humidity, % | Precipitation, mm | |
| April | 4.7 | 69 | 25.1 | 12.2 | 22 | 31.8 | 12.8 | 73 | 22.2 |
| May | 13.5 | 65 | 46.3 | 16.0 | 55 | 21.1 | 16.4 | 63 | 21.7 |
| June | 19.3 | 59 | 33.8 | 17.0 | 70 | 104.5 | 18.3 | 70 | 36.2 |
| July | 20.7 | 63 | 68.8 | 23.3 | 56 | 23.6 | 24.0 | 59 | 31.2 |
| August | 19.7 | 56 | 44.8 | 22.8 | 58 | 2.9 | 24.7 | 63 | 11.3 |
| September | 15.2 | 63 | 17.3 | 14.3 | 59 | 14.6 | 15.9 | 66 | 48.0 |
| October | 6.0 | 69 | 10.0 | 11.6 | 66 | 32.3 | 13.5 | 76 | 25.0 |
Analyzing the data in Table 1, it can be said that the weather conditions in the Kherson region in 2025 were characterized by higher average monthly air temperatures throughout the growing season compared to average monthly air temperatures for the same period in the Dnipropetrovsk region.
Weather conditions in the Dnipropetrovsk region in 2024 and 2025 were also not identical. The average monthly air temperature during the growing season in 2025 was 2-3°C higher, and relative humidity was 5-10% lower than in 2024. Consequently, weather conditions in the experimental years at different geographic locations and in different years were not identical, and therefore had different effects on plant growth and development.
Research results: tomato yield
Phenological observations and plant measurements during the growing season showed that plants treated with Adept Agro.Bio grew and developed faster, which subsequently impacted fruit ripening time and yield. In the treatments treated with this product, ripe fruit was obtained earlier and yields were higher.
In 2024, chemical analyses of tomato leaves were conducted during the 2-3 leaflet and budding stages. The results showed that, under the influence of Adept Agro.Bio, leaf sugar content increased by 0.9-1.2%, chlorophyll content by 150 mg per 100 grams of raw material, and protein and total nitrogen content by 1.8% during the 2-3 leaflet stage, compared to the unfertilized control. Mineral fertilizers also activated biochemical processes in the leaves, but to a lesser extent than the complex humic preparation.
Experiments showed that Adept Agro.Bio (2 l/ha) promoted vigorous foliage growth, increased fruit production per plant, and increased fruit weight in both locations.
Table 2. The effect of humic fertilizers on tomato yield depending on soil types and climatic conditions (vegetation experiments in 2024 and 2025)
| Experimental options | Ordinary chernozem | Chestnut soil | ||||||
|---|---|---|---|---|---|---|---|---|
| Fruit yield, g per vessel | % to control | Number of fruits, pcs. | Weight of one fruit, g | Raw weight of tops, g | Fruit yield, g per vessel | % to control | Number of fruits, pcs. | |
| Dnepr, 2024 | ||||||||
| Used vehicle inspection | 106 | — | 2.0 | 50 | 391 | 102 | — | 2.0 |
| Adept Agro.Bio (2 l/ha) | 353 | 233 | 3.5 | 88 | 823 | 388 | 280 | 4.5 |
| NP, equivalent to the drug | 332 | 213 | 4.0 | 76 | 783 | 309 | 203 | 3.0 |
| Dnepr, 2025 | ||||||||
| Used vehicle inspection | 125 | — | 2.0 | 56 | 391 | 168 | — | 2.0 |
| Adept Agro.Bio (2 l/ha) | 308 | 146 | 3.6 | 92 | 874 | 433 | 158 | 5.0 |
| NP, equivalent to the drug | 281 | 124 | 3.5 | 80 | 743 | 336 | 100 | 4.0 |
| Kherson, 2025 | ||||||||
| Used vehicle inspection | 184 | — | 3.0 | 60 | 502 | 210 | — | 3.0 |
| Adept Agro.Bio (2 l/ha) | 296 | 64 | 4.0 | 72 | 644 | 429 | 105 | 5.0 |
| NP, equivalent to the drug | 264 | 43 | 3.5 | 75 | 813 | 328 | 56 | 5.0 |
After analyzing the product's effectiveness on different soils at a single location (Dnipro), it was noted that in 2024 and 2025, the increase from using Adept Agro.Bio on chestnut soil was higher than on chernozem soil. Furthermore, yield increases from using the product in 2024 on both soils were almost twice as high as in 2025. This indicates that the effectiveness of humic fertilizers depends not only on the soil types they are applied to but also on weather conditions during the years of application.
The 2025 trials, conducted at two locations, confirm that the stimulating effect of humic fertilizers depends on climatic conditions. Adept Agro.Bio's effectiveness in the 2025 trials was higher under Dnieper conditions on both soil types.
Here, when using Adept Agro.Bio on black soil, the yield increase was 146% compared to the control, which is 22% higher than the yield increase obtained with the mineral equivalent. On chestnut soil, the yield increase was 158%, or 58% higher than the increase obtained with the mineral equivalent.
In Kherson, the increase from the product was 64% on black soil and 105% on chestnut soil compared to the control. The product's advantage over the mineral equivalent remained approximately the same as in Dnipro. We believe the reduced effect of the product in Dnipropetrovsk Oblast in 2025, which has higher temperatures than 2024, and especially in Kherson Oblast, is due to the increased stimulating effect of humic acids in the soil itself and the activation of microbiological processes in it. This idea is supported by the increased yield in the control samples at both locations.
Impact on the quality of tomato fruits
The influence of humic fertilizers on the quality of tomato fruits was also studied.
Table 3. The effect of humic fertilizers on the quality of tomato fruits depending on soil types and climatic conditions
| Experimental options | Ordinary chernozem | Chestnut soils | ||||
|---|---|---|---|---|---|---|
| Total sugars, % | Vitamin C, mg% | Total acidity, % | Total sugars, % | Vitamin C, mg% | Total acidity, % | |
| Dnepr, 2024 | ||||||
| Used vehicle inspection | 2.5 | 15.8 | 0.56 | 2.0 | 10.9 | 0.47 |
| Adept Agro.Bio (2 l/ha) | 2.9 | 18.2 | 0.46 | 2.5 | 15.6 | 0.56 |
| NP, equivalent to the drug | 2.7 | 14.7 | 0.48 | 2.3 | 13.1 | 0.75 |
| Dnepr, 2025 | ||||||
| Used vehicle inspection | 2.6 | 23.0 | 0.43 | 2.8 | 23.7 | 0.30 |
| Adept Agro.Bio (2 l/ha) | 3.7 | 31.1 | 0.32 | 3.4 | 37.3 | 0.36 |
| NP, equivalent to the drug | 2.7 | 29.5 | 0.30 | 2.9 | 26.0 | 0.44 |
| Kherson, 2025 | ||||||
| Used vehicle inspection | 2.2 | 16.3 | 0.44 | 2.4 | 18.0 | 0.44 |
| Adept Agro.Bio (2 l/ha) | 3.2 | 24.9 | 0.37 | 3.2 | 22.3 | 0.44 |
| NP, equivalent to the drug | 2.6 | 16.9 | 0.28 | 2.6 | 18.0 | 0.55 |
The data in this table show that Adept Agro.Bio increased sugar and vitamin C content in both soil types compared to the unfertilized control in the Dnipropetrovsk and Kherson regions. The effect of mineral equivalent on tomato fruit quality was intermediate between the control and the Adept Agro.Bio-treated variants.
The effect of Adept Agro.Bio on the sugar content of tomato fruits was greater under dry climate conditions.
Conclusions
- The effectiveness of humic fertilizers depends on the soil: it is higher on chestnut soil, and lower on ordinary chernozem, which is due to the different stimulating effects of humic acids in the soils themselves.
- The degree of positive effect of humic fertilizers depends on the climatic conditions of the experimental sites, as well as on the weather conditions during the experiments.
- Humic fertilizers improve the quality of tomato fruits on both soils, but more so on black soil.
- There was some correlation between tomato quality and weather conditions. Under hotter and drier conditions, tomato quality was slightly better.
Agro.Bio 's modern biotechnologies are a logical and high-tech development of these fundamental approaches. Adept Agro.Bio, created using high-quality Ukrainian leonardite, effectively mitigates climate stress and maximizes the genetic potential of crops. The introduction of such innovative organomineral complexes ensures Ukrainian farmers consistently increase the yield and quality of vegetable produce in various soil types.