Influence of Microelements Incorporated into Agro.Bio Microfertilizer Products and Their Efficiency in Ukraine
To investigate the potential use of microelements to enhance the efficiency of fertilizers applied in rows, the following studies were conducted:
- Microelements were incorporated into preparations at various doses.
- Microelements were added to a line of monocomplex products, with nitrogen and potassium included in some cases. Field trials were conducted with these fertilizers on spring and winter wheat, taking into account varietal characteristics.
- Microelements were incorporated into liquid potassium humate, with which vegetative trials were conducted on winter wheat.
Observations showed that microelements (boron and manganese) combined with potassium humate produce an effect comparable to that of complete mineral fertilizer (NPK).
Optimization of Microelement Doses
When studying the doses and ratios of microelements in row application of potassium humate, it was established that the most effective dose of boron and manganese for spring and winter wheat is manganese sulfate at 5% of the weight of superphosphate.
Row application of potassium humate enriched with microelements promoted better plant rooting, which is a critical factor in the arid conditions of the Steppe. For example, in hard spring wheat, the total number of primary and secondary roots in 100 plants was 730 in the variant with low-concentration humate, 1907 in the variant with boron-enriched potassium humate, and 906 with manganese (data from a lysimetric trial). Similar results were obtained for soft spring wheat.
Impact on Aboveground Biomass
Determination of the total weight of aboveground biomass, conducted at various growth and development stages of wheat, showed a positive effect of potassium humate enriched with boron and manganese throughout plant development, with the effect intensifying at the ripening stage. For example, in winter wheat during the stem elongation phase, enriching potassium humate with boron increased the total aboveground biomass weight by 21.6% compared to the control (low concentration), and with manganese by 8.1%. At the waxy ripeness stage, the difference was 36.6% for boron and 33.3% for manganese.
Impact on Rudimentary Spike Formation
Microelements (boron and manganese) incorporated into Agro.Bio preparations positively influenced the formation of the rudimentary spike in spring wheat. The results of observations on the growth and differentiation of the rudimentary spike are presented in the table below.
Table 5. Influence of Boron and Manganese on the Size of the Rudimentary Spike in Spring Wheat (Spike Length, mm)
| Trial Scheme | Variety №1 | Variety №2 | ||||||
|---|---|---|---|---|---|---|---|---|
| Number of Leaves at Sampling | Number of Leaves at Sampling | |||||||
| 3 | 4 | 5 | 6 | 3 | 4 | 5 | 6 | |
| Potassium Humate | 0.163 | — | 3.700 | 9.400 | 0.230 | 0.295 | 2.300 | 7.700 |
| Humate + Boron “Agro.Bio” | 0.145 | — | 3.000 | 12.500 | 0.265 | 0.310 | 2.500 | 9.600 |
| Humate + Mn “Agro.Bio” | 0.176 | — | 2.700 | 11.500 | 0.193 | 0.345 | 2.700 | 9.900 |
| NPK + Potassium Humate | 0.236 | — | 4.400 | 20.500 | 0.260 | 0.422 | 2.500 | 9.200 |
| NPK + Humate + Boron “Agro.Bio” | 0.306 | — | 4.400 | 23.000 | 0.230 | 0.468 | 2.800 | 9.900 |
| NPK + Humate + Mn “Agro.Bio” | 0.270 | — | 6.000 | 24.300 | 0.215 | 0.530 | 2.900 | 10.500 |
Note: Potassium humate in all trial variants was applied at a rate of 2 l/ha P₂O₅.
For hard spring wheat variety №1, boron incorporated into the monocomplex fertilizer slightly delayed rudimentary spike growth in the 3–5 leaf stages, but this positively affected the formation of a greater number of spikelets and florets in the spike. In the six-leaf stage, the difference in spike size between the low-concentration potassium humate variant and the boron-enriched variant was noticeable, with the spike being significantly larger in the boron variant.
Manganese promoted faster rudimentary spike growth in the initial phase (start of tillering) compared to low-concentration potassium humate and boron-enriched potassium humate + B. However, in the five-leaf stage, spike growth under manganese influence slowed slightly, lagging behind the boron and low-concentration potassium humate variants. In the six-leaf stage, the spike grew but remained smaller than in the boron variant.
Joint application of microelement-enriched potassium humate with potassium and nitrogen fertilizers positively influenced rudimentary spike growth in all growth stages of hard spring wheat variety №1, with manganese providing better growth compared to boron.
For soft spring wheat variety №2, boron caused rapid rudimentary spike growth in all stages, from the start of tillering to heading. Manganese slightly delayed spike growth in early stages but stimulated it in later stages.
Impact on Crop Structure
Microelements positively influenced the growth and differentiation of the rudimentary spike, promoting greater spikelet and floret formation, which increased spike grain content. For example, in winter wheat, the low-concentration potassium humate variant had 672 spikelets and 1081 grains per 100 spikes, while the Monocomplex Humate + B variant enriched with boron had 882 spikelets and 1245 grains. The weight of 100 grains increased from 31.6 g to 33.93 g, plant height from 94.62 cm to 102.3 cm, and spike length from 4.9 cm to 5.6 cm.
Yield
Grain yield data for spring and winter wheat showed that the influence of microelements on crop structure affected its magnitude. For spring wheat, all five studied varieties responded positively to the application of Monocomplex Humate + B enriched with boron, though to varying degrees: variety №1 — 23.9% increase, variety №2 — 19.7%, variety №3 — 8.6%, variety №4 — 4.7%, variety №5 — 1.8% (laboratory-field trial).
Table 6. Influence of Microelements on Spring Wheat Grain Yield (Based on Trials in Kherson Region, 2-Year Average)
| Trial Variants | Variety №1 | Variety №2 | ||||||
|---|---|---|---|---|---|---|---|---|
| Grain Yield, c/ha | Yield Increase | Grain Yield, c/ha | Yield Increase | |||||
| c/ha | % | per 1 kg P₂O₅, kg | c/ha | % | per 1 kg P₂O₅, kg | |||
| No Fertilizers | 8.3 | — | — | — | 8.0 | — | — | — |
| Low-Concentration Potassium Humate | 9.7 | 1.4 | 16.8 | 14.0 | 8.9 | 0.9 | 11.2 | 9.0 |
| Monocomplex Humate + B | 10.7 | 2.4 | 28.9 | 24.0 | 9.1 | 1.1 | 13.8 | 11.0 |
| Monocomplex Humate + Mn | 10.6 | 2.3 | 27.7 | 23.0 | 8.7 | 0.7 | 8.8 | 7.0 |
Note:
- In 2013: variety №1 — P=2.4%, variety №2 — P=2.9%.
- In 2014: variety №1 — P=1.6%, variety №2 — P=2.5%.
- Potassium humate was applied at a rate of 2 l/ha P₂O₅.
Trials with winter wheat, conducted over 5 years, also confirmed the positive effect of two monocomplexes, boron and manganese, on enhancing fertilizer efficiency and nutrient utilization.
Table 7. Influence of Microelements on Enhancing Potassium Humate Efficiency Applied to Winter Wheat
| Trial Scheme | Control Field №1 (2013–2014 Average) | Control Field №2 (2015–2016 Average) | Control Field №3 (2016) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Grain Yield, c/ha | Yield Increase | Grain Yield, c/ha | Yield Increase | Grain Yield, c/ha | Yield Increase | |||||||
| c/ha | % | per 1 kg P₂O₅, kg | c/ha | % | per 1 kg P₂O₅, kg | c/ha | % | per 1 kg P₂O₅, kg | ||||
| No Fertilizers | 31.7 | — | — | — | 14.6 | — | — | — | 16.0 | — | — | — |
| Low-Concentration Potassium Humate | 34.1 | — | — | 48.0 | 15.5 | — | — | 18.0 | 19.8 | — | — | 76.0 |
| Monocomplex Humate + B | 36.4 | 2.3 | 6.7 | 94.0 | 16.7 | 1.2 | 7.7 | 42.0 | 20.8 | 1.0 | 5.0 | 96.0 |
| Monocomplex Humate + Mn | — | — | — | — | 16.6 | 1.1 | 7.0 | 40.0 | 20.8 | 1.0 | 5.0 | 96.0 |
Note:
- Control Field №1: Winter wheat sown on fallow (2013 — P=1.35%, 2014 — P=1.06%).
- Control Field №2 (2015–2016) and Field №3 (2016): Winter wheat sown after a stubble predecessor.
- Trials were conducted in single replication with a recorded plot area of 1 ha.
Organomineral Preparations with Microelements
Incorporating organic fertilizers into preparations increases their efficiency. In a series of trials, microelements were added to organomineral fertilizers made from humus and humate. Studies from 2013–2015 on three control fields in the Kherson region with spring wheat showed that boron incorporated into organomineral fertilizers from humus and potassium humate (1:1) increased grain yield for variety №1 by 36.4% and for variety №2 by 4.4% compared to low-concentration humate. Boron in a monocomplex from complete mineral fertilizer (NPK) increased yield for variety №1 by 11.3% and for variety №2 by 5.4%.
Table 8. Influence of Microelements on Enhancing Organomineral Fertilizer Efficiency for Winter Wheat
| Trial Variants | Control Field №2 (2015–2016 Average) | Control Field №3 (2016) | ||||||
|---|---|---|---|---|---|---|---|---|
| Grain Yield, c/ha | Yield Increase | Grain Yield, c/ha | Yield Increase | |||||
| c/ha | % | per 1 kg P₂O₅, kg | c/ha | % | per 1 kg P₂O₅, kg | |||
| No Fertilizers | 14.6 | — | — | — | 16.05 | — | — | — |
| Potassium Humate | 16.0 | — | — | 28 | 21.85 | — | — | 116 |
| Monocomplex Humate + B | 17.8 | 1.8 | 11.2 | 64 | 24.93 | 3.08 | 14.0 | 117 |
| Monocomplex Humate + Mn | 17.7 | 1.7 | 10.6 | 62 | 23.90 | 2.05 | 13.8 | 157 |
Note:
- Potassium humate was applied at a 1:1 ratio at a rate of 2 l/ha P₂O₅.
- Trials were conducted in single replication with a recorded plot area of 1 ha after a stubble predecessor.
Influence of Microelements on Humate
To enhance humate efficiency, the influence of microelements on the solubility of humic and fulvic acids was studied, as only soluble humates are physiologically active. Microelements were incorporated into humate at various ratios of leonardite, ammonia water, and superphosphate.
Table 9. Influence of Microelements Incorporated into Agro.Bio Preparations on Humic Acid Content (%)
| Fertilizer Composition | Leonardite to Superphosphate Ratio | Under Different Extraction Conditions | ||
|---|---|---|---|---|
| 30-Minute Boiling with 2% KOH | 10-Day Settling with NaOH in Cold | 10-Day Settling with H₂O in Cold | ||
| Leonardite 75 g, P₂O₅ 25 g, NH₄OH 25 ml | 3:1 | 8.0 | 0.10 | 0.020 |
| Leonardite 75 g, P₂O₅ 25 g, NH₄OH 25 ml + Boron 1.25 g | 3:1 | 10.0 | 0.12 | 0.020 |
| Leonardite 75 g, P₂O₅ 25 g, NH₄OH 25 ml + MnSO₄ 1.25 g | 3:1 | 10.0 | 0.12 | 0.020 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml | 9:1 | 30.0 | 0.10 | 0.015 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + Boron 1 g | 9:1 | 30.0 | 0.12 | 0.025 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + Boron 2 g | 9:1 | 32.5 | 0.12 | 0.040 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + Boron in Solution 2 g | 9:1 | 30.0 | 0.12 | 0.025 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + MnSO₄ 1 g | 9:1 | 32.0 | 0.12 | 0.020 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + MnSO₄ in Solution 1 g | 9:1 | 25.0 | 0.12 | 0.020 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + MnSO₄ 2 g | 9:1 | 22.2 | 0.12 | 0.020 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + MnSO₄ in Solution 2 g | 9:1 | 22.2 | 0.12 | 0.020 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + KMnO₄ in Solution 0.1 g | 9:1 | 22.5 | 0.10 | 0.025 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + KMnO₄ in Solution 0.2 g | 9:1 | 25.0 | 0.10 | 0.025 |
| Leonardite 90 g, P₂O₅ 10 g, NH₄OH 15 ml + KMnO₄ in Solution 0.25 g | 9:1 | 20.0 | 0.10 | 0.030 |
Microelements (boron and manganese) influence the solubility of humic acids. At a 3:1 ratio, boron and manganese sulfate increased the humic acid content. At a 9:1 ratio, boron increased the amount of soluble humic acids, with the amount increasing with higher boron doses. Manganese sulfate performed better in undissolved form, but increasing its dose reduced humic acid yield. Potassium permanganate (KMnO₄) in all variants reduced the percentage of soluble humic acids.
Table 10. Influence of Microelements Incorporated into Humus and Potassium Humate Preparations on Humic Acid Content (%)
| Trial Scheme | Humus to Potassium Humate Ratio | Under Different Extraction Conditions | |
|---|---|---|---|
| 30-Minute Boiling with 2% KOH | 10-Day Settling with H₂O in Cold | ||
| Humus 50 g, Potassium Humate 50 g | 1:1 | 0.3 | 0.030 |
| Humus 50 g, Potassium Humate 50 g + MnSO₄ (5% of Humate Weight) | 1:1 | 0.3 | 0.035 |
| Humus 50 g, Potassium Humate 50 g + KMnO₄ (5% of Humate Weight) | 1:1 | 0.4 | 0.045 |
| Humus 50 g, Potassium Humate 50 g + Boron (5% of Humate Weight) | 1:1 | 0.5 | 0.045 |
Boron and manganese incorporated into Agro.Bio preparations from humus and potassium humate (1:1) positively influenced humic acid solubility. The best effect was achieved with boron. Among manganese preparations, potassium permanganate showed the best result.
Microvegetative Trials with Humate
To assess the feasibility of field trials with microelement-enriched humate, two preliminary vegetative trials were conducted.
Table 11. Influence of Different Microelement Doses in Humate on the Weight of Root and Aboveground Biomass of Winter Wheat in Microvegetative Trials in Soil Culture
| Variant | Air-Dry Biomass Weight of 10 Plants | % Compared to Control | ||||
|---|---|---|---|---|---|---|
| Grams | Including | Roots | Stems | |||
| Total Weight, g | Roots, g | Stems, g | ||||
| Microvegetative Trial №1 | ||||||
| Potassium Humate | 445 | 55 | 390 | 100 | 100 | |
| Humate + Boron “Agro.Bio” (10% Concentration) | 762 | 103 | 659 | 187.2 | 168.9 | |
| Humate + Boron “Agro.Bio” (20% Concentration) | 574 | 66 | 508 | 120.0 | 130.2 | |
| Humate + Manganese “Agro.Bio” (10% Concentration) | 711 | 87 | 624 | 158.1 | 160.0 | |
| Humate + Manganese “Agro.Bio” (20% Concentration) | 502 | 51 | 541 | 92.7 | 115.6 | |
| Humate + Manganese + Potassium “Agro.Bio” (1% Concentration) | 528 | 75 | 453 | 136.3 | 116.1 | |
| Humate + Manganese + Potassium “Agro.Bio” (2% Concentration) | 557 | 67 | 490 | 121.8 | 125.6 | |
| Microvegetative Trial №2 | ||||||
| Potassium Humate | 276 | 35 | 241 | 100 | 100 | |
| Humate + Boron “Agro.Bio” (10% Concentration) | 293 | 34 | 259 | 97.1 | 107.4 | |
| Humate + Manganese “Agro.Bio” (10% Concentration) | 252 | 35 | 217 | 100 | 90.0 | |
Note: All variants were balanced for phosphorus. Seeds were treated with liquid fertilizer.
In microvegetative trial №1, boron incorporated into potassium humate significantly increased root biomass weight. Manganese also promoted root mass increase, with an optimal concentration of 10% boron and manganese sulfate. For potassium permanganate, the best result was achieved at 1%. Aboveground biomass developed more intensively at 10% boron, 10% manganese sulfate, and 2% potassium permanganate.
In microvegetative trial №2, no significant differences were observed, likely due to early harvesting (two-leaf stage), when fertilizers did not have sufficient time to exert an effect.
Conclusions
- Boron and manganese incorporated into Agro.Bio preparations significantly enhance their efficiency (yield increase nearly doubles).
- Humate with microelements and humus enhances fertilizer action.
- The best leonardite-to-superphosphate ratio for humic acid yield is 9:1. Microelements are more effective in undissolved form, and manganese sulfate is preferable for humic acid yield and cost.