Innovative nutrient management practices for soybean production in southern Kazakhstan

Abstract

The southern regions of Kazakhstan, characterized by aridity and a continental climate, are currently facing a complex interplay of emerging challenges in the agricultural sector. Therefore, transitioning to advanced agrotechnologies in soybean production in this region might support broader science-driven solutions. Field trials were conducted between 2021 and 2023 to assess the effects of plant growth stimulator and micronutrients on soybean productivity under the harsh conditions of South Kazakhstan. The treatments were as follows: control without any application; seed priming with Vimpel (0.5 L/ton) and Orakul (1.5 L/ton) was applied in T1. In T2 and T3, these applications were supplemented with foliar treatments of Vimpel (0.5 L/ha) and Orakul (2.0 L/ha) at the 3–5 leaf stage and the bud formation stage. In T4, additional foliar Vimpel (0.5 L/ha), Orakul (2.0 L/ha), and Orakul Kolofermin (2.0 L/ha) were applied at the bud formulation stage. Results showed that soybean yield increased progressively in response to the multi-stage application of plant growth stimulator along with micronutrients. The grain yield reached 2063 and 2,185 kg/ha in T2 and T3, surpassing the control by 30.4 and 38.1%, respectively. The greatest increase (54.6%) was observed in T4, highlighting the potential of the multi-stage applications for greater efficacy with balanced nutrient interventions. In this treatment, the water productivity (WP) value also enhanced by 48.6% and the harvest index (HI) by 17.9%, contributing to more efficient water use strategies. This study presents the advantages of the applied innovative nutrient management practices in enhancing soybean production under adverse agroecosystems in southern Kazakhstan, while simultaneously reducing dependence on widely used chemical fertilizers.

Introduction

Crop production in Central Asia is experiencing significant challenges due to human-induced climate change coupled with dwindling water resources, leading to ecological and economic problems for rural populations. Especially, water deficiency is becoming increasingly critical issue for the lower reaches of major rivers, particularly across diverse landscapes of Southern Kazakhstan (Amangaliev et al., 2023). Furthermore, the volume of precipitation in this region is gradually declining, exacerbating the challenge. This situation is further worsened by land degradation and salinization as well as the growing population which puts pressure on the agrifood sector (Khaitov et al., 2025; Nurbekov et al., 2025).

According to recent estimates, the extent of irrigated land in Kazakhstan may decline sharply in the future, while the preservation of natural ecosystems within river basins may become increasingly difficult (Yakimenko et al., 2016). The area suitable for irrigation is more than 60 million hectares in Kazakhstan, while up to 5 million hectares of land and about 2.4 million hectares of estuaries can be irrigated with locally available water resources (Didorenko, 2014). This underscores the urgent need to prioritize the efficient use of water in agriculture and to invest in sustainable, long-term solutions. In this regard, urgent action is required to mitigate and adapt to the effects of climate change by transitioning toward more sustainable farming, avoiding resource depletion and environmental threats (Nurbekov et al., 2023). Furthermore, strategic planning aimed at stabilizing agroecosystems and the modernization of crop production technologies are of great importance in the face of growing water scarcity and climate uncertainty.

Soybean is the world’s most grown legume, belonging to the Glycine genus within the Fabaceae family. This cultivar is used in a wide range of food products, including oil, margarine, soy cheese, milk, flour, confectionery, canned food. With a protein content of up to 47%, soybean seeds hold significant value as both a food source and animal feed. Expanding industrial processing of soybeans and promoting the use of soy protein products for human consumption represent effective strategies to address the existing protein deficit and enhance the nutritional profile of the population (Makulbekova et al., 2017). Beyond its food and feed uses, soybean with N fixing bacteria in its roots enhances the activity of soil microorganisms and improves soil health.

The existing cultivation practices are unsuitable for achieving long-term sustainability of soybean production. In most cases, traditional intensive agricultural practices accompanied by high doses of chemical fertilizers, have led to the depletion of soil nutrients and a significant decline in crop yields. Moreover, the excessive reliance on chemical inputs has disrupted soil microbial activity, reduced organic matter content, and increased vulnerability to pests and diseases (Yerzhebayeva et al., 2024). As a result, farmers face increasing challenges in maintaining productivity due to declining soil fertility, reduced irrigation efficiency and enhanced vulnerability to climate variability.

Building resilient and sustainable agricultural systems requires targeted strategies to address long-term challenges while restoring ecosystem services (Namozov et al., 2022). In this context, the key obstacles to achieving high and stable soybean yields in southern Kazakhstan are linked to the limited adoption of modern approaches such as digital, precision, and regenerative agriculture (Kipshakbayeva et al., 2024). Recent innovations in plant nutrition involving nano-, micro-, and bio-nutrients have demonstrated substantial improvements in crop yield, environmental safety and energy efficiency (Khaitov, 2018; Israilov et al., 2025). Despite growing recognition of their potential, the use of these precision agriculture techniques in soybean production such as optimized nutrition methods has not been practiced enough, particularly under the marginal conditions of southern Kazakhstan (Beisenbayeva et al., 2021).

This study hypothesized that applying growth stimulants together with microfertilizers, while accounting for complex soil–climate conditions, might alleviate nutrient deficiencies in soybean grown under dryland agriculture and enhance crop productivity. These innovative strategies are of considerable practical importance to agricultural science and contribute to long-term sustainable solutions for soybean production under the adverse climatic conditions of southern Kazakhstan. Furthermore, these innovative nutrient management practices might play a critical role in regional food security and ecosystem restoration by preserving agrobiodiversity, soil health and ecosystem services. Given the complexity of the soil–climatic conditions in the region, this study focused on evaluating the effectiveness of growth stimulants and their combination with microfertilizers in soybean production.

Materials and methods

Soil and climatic conditions

Field experiments were conducted at the stationary site of the Department of Agriculture and Plant Industry, South-West Research Institute of Animal Husbandry and Plant Industry between 2021 and 2023. Soil cover of the research area is represented by ordinary gray soils developed on a thick thickness of loess-like loams and sandy loams. The mechanical composition of the upper horizon is characterized as medium loam, gray in color, dry, and dense. The upper part exhibits a horizontal, layered-platy structure, while deeper layers transition into a blocky, nearly massive formation with a coarse, knobby fracture. The lower horizon contains roots and has a heavy loam texture.

The average depth of the plow layer is approximately 22.5 cm. Its chemical composition, based on research conducted from 2021 to 2023, is as follows: humus content ranged from 1.36 to 2.02%. Available phosphorus varied between 9.5 and 25.0 mg/kg, nitrate nitrogen ranged from 5.2 to 22.4 mg/kg, exchangeable potassium was found in concentrations of 247 to 310 mg/kg, carbon dioxide (CO₂) content ranged from 6.71 to 8.64% (Table 1).

Agrometeorological data were obtained from the weather station “Shymkent-Agro,” located directly at the stationary site of the institute. The Turkestan region is situated in the extreme south of the Republic of Kazakhstan and, from a physical and geographical perspective, encompasses a substantial portion of the high mountain ranges of the Western Tien Shan, their adjacent lowland plains, and the expansive territories of the Turkestan (Turan) lowland. Due to the considerable distance of the Western Tien Shan from oceans and seas, the region experiences a sharply continental climate characterized by dry autumns, wet springs, hot summers, and mild, moist winters. The hottest month is July, with an average temperature of 26.8 °C, while January is the coldest, averaging −0.4 °C. Air temperatures exceeding 10 °C typically begin in the second 10-day period of April and persist until the end of September. The frost-free period averages 222 days, with annual fluctuations ranging from 210 to 234 days.

Evaporation measured averages 1,240 mm annually, while during summer months it reaches 222–283 mm per month. Throughout the soybean growing season, evaporation ranged from 927 to 1,137 mm, exceeding precipitation levels by a factor of 9 to 10. This imbalance highlights the critical need for regular irrigation (Figure 1).

Figure 1

In the southern regions of Kazakhstan, the primary limiting factor for crop productivity including soybean is soil moisture. During the soybean growing season, precipitation is insufficient, and the moisture reserves accumulated from autumn and winter are inadequate to meet the water demands of this valuable leguminous crop. Kazakhstan’s abundance of sunlight and thermal resources creates favorable conditions for soybean cultivation.

Soybean cultivars tested in the experiment

For this study, the late maturing soybean variety “Lastochka” was chosen, as it is widely cultivated across the territory of Kazakhstan. This cultivar is particularly valued for its resilience to heat and drought stress, consistently exhibiting stable yield performance and high protein content. Therefore, “Lastochka” serves as a preferred choice among farmers for its drought-resistance and heat tolerance traits, while provides balanced productivity with environmental constraints. The vegetation period of the late-maturing soybean variety “Lastochka” typically ranges from 122 to 126 days. The soybean growing season typically runs from late April/early May to October, depending on weather conditions. This soybean variety “Lastochka” has shown a yield potential of about 2.5–3.0 tons per hectare under favorable irrigated conditions.

Plant growth stimulators and micronutrient treatments

Plant growth stimulant “Vympel”—complex natural-synthetic preparation, contact-system action for treatment of seeds and vegetative plants. Composition: polyethylene oxides (PEO) - 770 g/L, washed salts of humic acids up to 30 g/L. Properties: growth stimulator, clinging agent, adaptogen, cryoprotector, thermoprotector, anti-stressant, disease inhibitor, soil activator, antioxidant.

“Orakul”—a unique complex liquid microfertilizer for the treatment of seeds of field, vegetable, ornamental crops, potato tubers, soaking cuttings, chubuki, seedlings of grapes and fruit and berry crops in order to root them. Treatment is carried out in tank mixtures with dressing agents. Composition: N-20 g/L, P₂O₅–99 g/L, K₂O-65 g/L, SO₃-57 g/L, Fe-15 g/L, Cu-5.4 g/L, Zn-5.4 g/L, B-1.8 g/L, Mn-15 g/L, Co-0.01 g/L, Mo-0.4 g/L.

“Orakul” multicomplex—used together with pesticides, growth stimulants, mineral fertilizer solutions with a wide pH range. Microfertilizer “Orakul” multicomplex contains a water softener. Composition: N-100 g/L, P₂O₅–66 g/L, K₂O-44 g/L, SO₃-36 g/L, Fe-6 g/L, Cu-8 g/L, B-6 g/L, Mn-6 g/L, Co-0.05 g/L, Mo-0.12 g/L.

“Orakul” molybdenum colofermine—concentrated microfertilizer for seed treatment of leguminous crops and foliar feeding of field, vegetable and perennial crops.

Compatibility: “Orakul” molybdenum colofermine is combined with herbicides, insecticides, fungicides and biopreparations. Before use, it is necessary to check for compatibility with the drugs in the tank mixture. The preparation has a slightly alkaline reaction, so the biological activity of nodule bacteria increases.

It is recommended to use together with plant growth stimulator “Vympel.” Composition: Mo-130 g/L, N-41 g/L, colofermin 255 g/L.

Experiment design

A Randomized Complete Block Design (RCBD) with four replications was used in this experiment, covering a total area of 3,600 m². Each plot measured 180 m² (30 m × 6 m), while the data collection area was 90 m². This was a single-factor experiment using foliar treatments in four combinations (T1–T4) compared to a control (without any treatment). Seeds were treated with the stimulant (Vimpel) and micronutrients (Orakul) prior to planting, and additional micronutrients were applied as foliar treatments during the vegetation period (Table 2). Seeds were planted in the last decade of April at a seeding rate of 120 kg/ha. The distance between rows was 70 cm, with 35 seeds planted per meter of row, totaling 550,000 seeds per hectare.

Data collection

Furrow irrigation was used in this study, as it is a widely accepted agricultural practice in the region. Annual irrigation volumes were recorded as 4,450 m³/ha in 2021, 4,530 m³/ha in 2022, and 4,350 m³/ha in 2023, indicating a modest fluctuation over the 3-year period. Water productivity (WP) was defined as a key indicator in agricultural water management, reflecting how efficiently water is converted into crop yield. The following formula was used in this experiment:

This gives WP in units of kg/m3 which measures how much crop yield is produced per unit of water supplied.

Leaf Area Index (LAI) is a key biophysical parameter that quantifies the extent of leaf surface area relative to the ground area it covers. In soybean, LAI is calculated as follows:

Accurate estimation of LAI is essential for evaluating crop growth, modeling productivity, and optimizing agronomic practices. Leaf area measurements were taken from five representative plants per treatment using a LI-COR 3100 leaf area meter. The leaf area index (LAI) was then calculated by dividing the total leaf area by the corresponding ground area.

Field observations were conducted across several phenological growth stages, including measurements of plant height (in centimeters), number of branches per plant, and chlorophyll content using a handheld SPAD-502 meter (KONICA MINOLTA). To estimate dry matter accumulation, destructive samples were collected from each plot area and dried in a lab oven at 60 °C until a constant weight was achieved.

Dried plant samples were ground and passed through a 2-mm sieve prior to chemical analysis. A mixture of 1 mL concentrated sulfuric acid and 10 mL of 50% perchloric acid was added to 0.5 g of the sample in a digestion tube, followed by heating on a hot plate to facilitate decomposition. Total nitrogen (N), phosphorus (P₂O₅), and potassium (K₂O) concentrations were determined using Kjeldahl distillation, the Vanadate method, and inductively coupled plasma spectrophotometry, respectively (NIAST, 2000).

The cumulative yield from the net plot area was recorded and expressed as kg per hectare (kg ha⁻¹).

Statistical analysis

Field experiments were laid by the method of split plots on irrigated lands according to the scheme of the experiment in four repetitions. Statistical analysis of the obtained data was processed with the ANOVA (CropStat) program. Mean comparisons were performed using the Least Significant Difference (LSD₀.₀₅).

Results and discussion

Soybean yield and water productivity

The results across three consecutive growing seasons (2021–2023) demonstrate a consistent and significant increase in soybean yield in response to the co-application of plant growth stimulators and micronutrient treatments (Table 3). Although chemical fertilizers were not applied in this experiment, the increase of soybean yield was positively associated with the multi-stage application of the tested treatments. The control plots, which received no treatment, yielded an average of 1,582 kg/ha, indicating an average yield can be achieved without additional nutrient inputs.

Compared to the control group, soybean yield increased by 8.5% under the first treatment (T1), which involved seed priming with the growth stimulator Vimpel (0.5 L/ton) and micronutrients Orakul (1.5 L/ton) prior planting. In the second treatment (T2), soybean yield reached 2063 kg/ha, surpassing the control by 30.4%. This improvement was achieved through a two-stage application: seed priming followed by treatment (Vimpel 0.5 L/ha + micronutrients Orakul 2.0 L/ha) at the 3–5 true leaf formation phase of soybean.

A further increase in soybean yield was observed under the third treatment (T3), which involved a three-stage application: seed priming, treatment at the 3–5 true leaf formation stage, and at the bud formation stage. This approach resulted in a yield of 2,185 kg/ha, surpassing the control by 38.1%. The highest soybean yield was recorded under the fourth treatment (T4), where plant growth stimulators were applied in combination with micronutrients across three vegetative stages. The progressive application of these compounds led to steadily increasing yields, with the most substantial improvement observed under the multi-stage treatment. Specifically, the T4 plots yielded 2,446 kg/ha, marking a 54.6% increase compared to the control. These findings indicate a beneficial relationship between the agronomic intervention namely, plant growth stimulators and micronutrient applications contributing to enhanced crop performance. The link between soybean yield and the applied treatments is due to the fact that effective nutrient management contributed to the increased soybean production (Bagale, 2021).

A similar trend was observed in the harvest index (HI) values of soybean. The control plots recorded an HI of 0.39, serving as the baseline for comparison. Treatment T1 led to a modest increase to 0.41, while T2 showed a more pronounced improvement, reaching 0.45. T3 maintained the same level at 0.45, and T4 produced the highest HI value of 0.46. These results demonstrate a clear positive relationship between the multi-stage treatments and HI performance. Compared to the control, T4 improved the harvest index by approximately 17.9%, indicating a notable agronomic advantage.

In addition to yield, water productivity (WP) values (ranging from 0.37 to 0.55) also show a consistent increase across treatments: control (0.37), T1 (0.40), T2 (0.47), T3 (0.48), and T4 (0.55).

Overall, the data suggest that T4 is the most effective in boosting both yield and WP. The consistent improvement across treatments was possibly linked to leveraging nutritional balance and the stimulatory effects of the applied compounds. The statistical analysis confirmed the significance of these differences and validate the robustness of the observed trends. Although the experiment was conducted over 3 consecutive years, statistical analysis revealed no significant differences across years for the majority of the tested parameters. Therefore, data were pooled and analyzed as mean values across years.

The efficacy of these treatments are especially evident in WP and crop output characteristics under the arid continental climate. The applied treatments in soybean cultivation may have enhanced plant physiological processes, thereby harmonizing with the development of climate resilience and contributing to stable yields. Understanding soybean nutrient uptake, accumulation, and partitioning throughout the growth stages is essential for identifying specific nutrient management techniques required for optimal growth and reproductive development (Barbosa et al., 2016). Recent studies have highlighted that the application of modern agrotechnological advancements such as biostimulators and micro fertilizers considerably enhances plant health and crop yield (Dass et al., 2022; Tarar et al., 2022).

Overall, the data obtained underscores the importance of the beneficial combination of nutrient management strategies in optimizing soybean productivity. The consistent yield improvements highlight the robustness of the applied treatments, while the additive effect suggests potential for further refinement in balanced nutrient protocols. These findings support the adoption of innovative nutrient management strategies to enhance soybean production under the harsh environmental conditions of South Kazakhstan.

Effect of the combined treatments on soybean vegetative and chemical parameters

This three-year field study was conducted to evaluate the impact of plant growth stimulators and micronutrient treatments on vegetative and generative parameters of soybean (Table 4). The variables assessed included plant height, height of attached lower beans, weight of 1,000 seeds, and length of the vegetation period. The results consistently demonstrated that the combined treatments positively influenced soybean growth and development, providing the plants with essential nutrients. Plant height increased progressively with each treatment stages, indicating enhanced vegetative vigor. In untreated control plots, average plant was 63.0 cm, whereas height values reached 74.2 cm in T1, 78.7 cm in T2, and 80.7 cm in T3. The highest value was observed in T4, exhibiting 84.7 cm. Each application of micronutrients along with plant growth stimulators contributed to an average increase of 3–5 cm across all treatments, likely due to improved resource allocation.

The height of the lowest attached beans is a critical characteristic for mechanical harvesting. Control plots averaged 8.0 cm, while T4 plot reached up to 8.8 cm. This upward shift suggests improved pod placement and canopy architecture, which may reduce pod loss during harvest.

Seed weight is a direct indicator of yield quality. Control plots averaged 139.8 g, while 142.6 g in T1, 143.9 g in T2 and 145.7 g in T3. The highest value was recorded the T4 plot (147.9 g). The consistent increase in seed weight across treatments reflects improved seed quality, possibly due to enhanced nutrient balance facilitated by the nutrition interventions.

The vegetation period extended slightly with increasing treatment stages. Control plots ranged from 120 to 122 days, while the T4 plot extended up to 127.7 days. The improved nutritional status may have facilitated the prolonged vegetation phase while also enhancing reproductive development. The data clearly indicate that the applied innovative nutrient management strategies significantly enhanced soybean performance. The effect is most pronounced in the multi-stage treatments, where improvements in plant morphology, seed quality, and phenological duration parameters are agronomically meaningful. These findings support the adoption of multi-stage treatment protocols and targeted nutrition balance to optimize soybean productivity under field conditions in southern Kazakhstan (Toishimanov et al., 2024).

Table 5 presents the effects of five treatments (Control, T1–T4) on shoot concentrations of nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). All tested treatments (T1–T4) improved plants’ nutrient contents compared to the control group. The results showed a consistent upward trend in nutrient accumulation with increasing treatment stages. The most pronounced effects were observed in T3 and T4, suggesting that multi-stage applications of plant growth stimulators and micronutrients are particularly effective.

T3 showed the highest N concentration (3.29%), a 45.6% increase over the control. Both (P and K) nutrients showed a plateau effect at T3 and T4, indicating that two or three-stage applications may be sufficient to reach optimal uptake levels. Ca and Mg concentrations also exhibited an increasing trend across the treatment stages, with T4 showing the highest values. This may reflect the increased availability of essential elements after the treatments, which likely enhanced enzymatic and physiological activity in the crop. While soybean seeds were not inoculated with bacterial strains prior to planting, indigenous microorganisms present in the soil may have influenced biological nitrogen fixation and nutrient mobilization. Previous studies have also reported the possibility of infecting legumes with indigenous rhizobial strains in long-term legume-cultivated lands (Khaitov et al., 2020).

Shoot nutrient concentrations of N, P, K, Ca, and Mg increased progressively across the treatment stages. The highest values were observed under T4, demonstrating that multi-stage applications of plant growth stimulators combined with micronutrients substantially improved plant nutrient concentrations. For instance, N concentration increased from 2.26% in the control to 3.29% in T4. Similarly, Ca and Mg reached their peak levels in T4, demonstrating the efficiency of the applied multi-stage treatment in improving plant nutrient balance. The observed improvements of soybean vegetative and generative parameters may result from a well-balanced nutrient supply during critical stages, where N stimulates vegetative growth, P supports root and fruit formation, and K contributes to overall plant vigor. Previous studies have also reported that foliar micronutrient application is an essential technique for fulfilling plant nutrient demands, thereby enhancing resistance to both abiotic and biotic stresses (Gheshlaghi et al., 2019; Stewart et al., 2020; Selvakumar et al., 2025).

Statistical analysis using LSD at p < 0.05 confirmed that T3 and T4 consistently outperformed the control across all measured parameters. The multi-stage treatments not only enhanced vegetative growth but also significantly improved the nutrient profile of soybean plants. This dual benefit supports higher yield potential and more sustainable nutrient management especially under the challenging agro-climatic conditions of southern Kazakhstan. The results of this study also confirmed that foliar micronutrient treatments in combination with growth stimulants may provide sustainable alternatives to conventional chemical fertilizers. By contrast, persistent dependence on chemical fertilizers has disrupted nutrient cycling, depleted soil organic matter, and intensified nitrogen and phosphorus losses to the environment (Setubal et al., 2023; Thapa et al., 2021; Wijerathna-Yapa and Pathirana, 2022).

The evaluated agronomic strategy effectively increased crop productivity, while mitigates adverse anthropogenic impacts on the environment. Therefore, rational use of plant growth stimulators along with micronutrients is recommended in soybean production programs that can positively affect nutrient balance and crop production.

Effect of the tested treatments on soybean leaf area index and biomass accumulation

Table 6 presents the effect of the combined treatments (T1–T4 and control) on leaf area index (LAI) at three key soybean growth stages: budding (1 June), flowering (1 July), and pod development (1 August). At this early stage, leaf area per plant ranged from 482 cm² in the control to 514 cm² in T3. However, LAI differences at this period were not statistically significant (NS), ranging narrowly from 0.30 to 0.34.

At the flowering stage, leaf area per plant increased progressively across all treatments, with T4 again showing the highest value (2,151 cm²), followed closely by T3 and T2. LAI values ranged from 2.48 in the control to 2.77 in T3. Treatments T3 and T4 significantly outperformed the control, indicating enhanced canopy expansion during the reproductive period.

By the pod development stage, leaf area per plant peaked in T4 (3,758 cm²), with T3 closely following (3,752 cm²). In terms of per hectare, LAI values were highest in T4 (3.64), followed by T3 (3.58), both significantly greater than the control (2.98). These results suggest that treatments T3 and T4 promoted leaf growth, which is critical for stimulating photosynthetic processes, followed by grain filling and yield formation.

Mean separation using LSD at p < 0.05 confirmed significant differences among treatments for leaf area and LAI at flowering and pod development stages. The use of lowercase letters (a–d) in the table indicates statistically significant groupings, with T4 consistently ranking highest.

Table 7 presents the biomass accumulation rate of soybean (g/m²/day) under five treatment conditions (T1–T4 and control) at two critical growth stages: budding and flowering. The results reveal clear treatment-induced improvements in biomass assimilation rates, with notable differences in both absolute values and percentage increases relative to the control.

Biomass accumulation rate at the budding stage was lowest in the control (7.91 g/m²/day). All treatments showed statistically significant improvements, with T4 recording the highest value (8.77 g/m²/day), representing a 10.87% increase over the control. T3 and T2 also demonstrated strong performance (8.54 and 8.42 g/m²/day, respectively), with gains of 7.96 and 6.45%, respectively. T1 showed a modest increase (8.07 g/m²/day), corresponding to a 2.02% improvement over the control.

At flowering, biomass accumulation increased progressively with successive treatment stages. The control reached 10.8 g/m²/day, while T4 again achieved the highest value (12.6 g/m²/day), marking a 16.67% improvement. Treatments T3 and T2 followed closely (11.4 and 11.3 g/m²/day), with gains of 5.56 and 4.63%, respectively. T1 showed a smaller increase (11.2 g/m²/day), equivalent to 3.7% over the control group. Mean separation using LSD at p < 0.05 confirmed that T4 significantly outperformed all other treatments at both growth stages. Treatments T2 and T3 also showed consistent superiority over the control, while T1 exhibited moderate improvements.

The applied growth stimulator and micronutrients effectively increased LAI and biomass accumulation rates, while significantly influencing the growth, yield components, and overall productivity of soybean under harsh environmental conditions. This indicates that the tested treatments might have stimulated photosynthetic processes in soybean, leading to significant increases in vegetative and generative parameters. This finding aligns with previous studies suggesting that this technique may serve as a viable alternative for reducing reliance on conventional chemical fertilizers (Trujillo-Tapia and Ramírez-Fuentes, 2016). These agrotechnologies were driven by the enhanced demand for soybean products in the face of climate variability and limited water resources (Heidarzade et al., 2016; Rawal et al., 2022). The layout of these advanced agricultural practices follows not only to food production but to reverse land degradation and foster resilient ecosystems.

Conclusion

This study showed that the combined application of plant growth stimulators and micronutrients had a consistent effect in enhancing soybean productivity, while also exhibiting the potential of reducing reliance on conventional chemical fertilizers. At T4, soybean yield increased by 54.6% when plant growth stimulators in combination with micronutrients were applied at the three stages: seed priming, treatment at the 3–5 true leaf formation stage, and at the bud formation stage. This treatment also enhanced WP value by 48.6% and HI by 17.9%, contributing to more efficient water use strategies.

This integrated approach represents a strategic potential for maintaining food security and promoting environmental sustainability under the challenging conditions of southern Kazakhstan. In addition to enhancing agricultural resilience, these cost-effective agronomic innovations ensure stable crop yields and support ecological balance in arid regions in the face of climate change and water scarcity.

References

• 1

  AmangalievB. M.ZhusupbekovE. K.MalimbaevaA. Z.BatyrbekM.RustemovaK. U.TabynbayevaL. K. (2023). Dynamics of fertility indicators of light-chestnut soil and oil flax productivity under bogarian conditions of Southeast Kazakhstan. SABRAO J. Breed. Genet.55, 2195–2206.

  • Google Scholar

• 2

  BagaleS. (2021). Nutrient management for soybean crops. Int. J. Agron.1:3304634.

  • Google Scholar

• 3

  BarbosaJ. M.RezendeC. F. A.LeandroW. M.RatkeR. F.FloresR. A.da SilvaÁ. R. (2016). Effects of micronutrients application on soybean yield. Aust. J. Crop. Sci.10, 1092–1097. doi: 10.21475/ajcs.2016.10.08.p7367

  • CrossRef
  • Google Scholar

• 4

  BeisenbayevaM.SeilkhanA.SydykD.ZhapparovaA.KaldybayevS.AzatS.et al. (2021). Soybean productivity as influenced by irrigation regime and fertilizer rates in the South Kazakhstan conditions. Res. Crops22, 34–45.

  • Google Scholar

• 5

  DassA.RajannaG. A.BabuS.LalS. K.ChoudharyA. K.SinghR.et al. (2022). Foliar application of macro-and micronutrients improves the productivity, economic returns, and resource-use efficiency of soybean in a semiarid climate. Sustainability14, 5825–5836. doi: 10.3390/su14105825

  • CrossRef
  • Google Scholar

• 6

  DidorenkoS. V. (2014). Achievements of irrigation works on soybeans in Kazakhstan. Bull. Agric. Sci. Kazakhstan1, 22–27.

  • Google Scholar

• 7

  GheshlaghiM. Z.PasariB.ShamsK.RokhzadiA.MohammadiK. (2019). The effect of micronutrient foliar application on yield, seed quality and some biochemical traits of soybean cultivars under drought stress. J. Plant Nutr.42, 2715–2730. doi: 10.1080/01904167.2019.1655034

  • CrossRef
  • Google Scholar

• 8

  HeidarzadeA.EsmaeiliM.BahmanyarM.AbbasiR. (2016). Response of soybean (Glycine max) to molybdenum and iron spray under well-watered and water deficit conditions. J. Exp. Biol. Agric. Sci.4, 37–46. doi: 10.18006/2015.4(1).37.46

  • CrossRef
  • Google Scholar

• 9

  IsrailovI.SindarovO.SalomovS.KhayitovK.BobokulovS.BegmatovI.et al. (2025). Agronomic efficiency of nano-integrated nutrient management on cotton yield traits under arid farming conditions. Front. Sustain. Food Syst.9:1695604.

  • Google Scholar

• 10

  KhaitovB. (2018). Effects of Rhizobium inoculation and magnesium application on growth and nodulation of soybean (Glycine max L.). J. Plant Nutr.41, 2057–2068. doi: 10.1080/01904167.2018.1485164

  • CrossRef
  • Google Scholar

• 11

  KhaitovB.RajabovN.MurtazayevaG.DurdievN.NorqulovU.AbdalovaG.et al. (2025). The effectiveness of bio-treatment on licorice (Glycyrrhiza glabra) productivity and soil restoration in saline ecosystems. Eur. J. Soil Sci.14, 198–207.

  • Google Scholar

• 12

  KhaitovB.VollmannJ.YeongP. J.ParkK. W. (2020). Improvement of salt tolerance and growth in common bean (Phaseolus vulgaris L.) by co-inoculation with native Rhizobial Strains. J. Agr. Sci. Tech.22, 209–220.

  • Google Scholar

• 13

  KipshakbayevaG.ZargarM.RysbekovaА.AshirbekovaI.TleulinaZ.AmantayevB.et al. (2024). Assessment of the genetic parameters of soybean genotypes for precocity and productivity in the various cultivation conditions. Heliyon10, 89–97. doi: 10.1016/j.heliyon.2024.e36135,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 14

  MakulbekovaA.IskakovA.KulkarniK. P.SongJ. T.LeeJ. D. (2017). Current status and future prospects of soybean production in Kazakhstan. Plant Breed. Biotechnol.5, 55–66. doi: 10.9787/pbb.2017.5.2.55

  • CrossRef
  • Google Scholar

• 15

  NamozovF.IslamovS.AtabaevM.AllanovK.KarimovA.KhaitovB.et al. (2022). Agronomic performance of soybean with bradyrhizobium inoculation in double-cropped farming. Agriculture12, 855–895. doi: 10.3390/agriculture12060855

  • CrossRef
  • Google Scholar

• 16

  NIAST (2000). Method of soil and plant analysis. Suwon: National Institute of Agricultural Science and Technology (NIAST).

  • Google Scholar

• 17

  NurbekovA.KhudaykulovJ.RakhimovM. (2023). Effect of planting date on productivity no-till maize in South Kazakhstan province of Kazakhstan. Sci. Inn.2, 141–145.

  • Google Scholar

• 18

  NurbekovA.UmarovS.AzizovS.UmarovM.KhaitovB.KhalilovaL.et al. (2025). Arid irrigated winter wheat and soybean cropping under conservation tillage systems. Front. Sustain. Food Syst.9:1512277. doi: 10.3389/fsufs.2025.1512277

  • CrossRef
  • Google Scholar

• 19

  RawalN.PandeK. R.ShresthaR.VistaS. P. (2022). Nutrient use efficiency (NUE) of wheat (Triticum aestivum L.) as affected by NPK fertilization. PLoS One17:e0262771. doi: 10.1371/journal.pone.0262771,

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 20

  SelvakumarS.RagavanT.GurusamyA.PrabhaharanJ.GunasekaranM.SivakumarT.et al. (2025). Impact of different nutrient management strategies on growth, yield components and yield of coloured cotton (Gossypium hirsutum L.) cv. Vaidehi 1. Front. Sustain. Food Syst.9:1544696. doi: 10.3389/fsufs.2025.1544696

  • CrossRef
  • Google Scholar

• 21

  SetubalI. S.Andrade JúniorA. S. D.SilvaS. P. D.RodriguesA. C.BonifácioA.SilvaE. H.et al. (2023). Macro and micro-nutrient accumulation and partitioning in soybean affected by water and nitrogen supply. Plants12, 1898–1907.

  • Google Scholar

• 22

  StewartZ. P.PaparozziE. T.WortmannC.JhaP. K.ShapiroC.A. (2020). Foliar micronutrient application for high-yield maize. Agronomy10:1946. doi: 10.3390/agronomy10121946

  • CrossRef
  • Google Scholar

• 23

  TararZ. H.AshrafW.AsgharS.HabibF.ShahS. A. H.KhaliqA.et al. (2022). A review on soil fertility and soybean yield improvement by managing micronutrients. J. Glob. Innov. Agric. Sci.10, 255–266.

  • Google Scholar

• 24

  ThapaS.BhandariA.GhimireR.XueQ.KidwaroF.GhatrehsamaniS.et al. (2021). Managing micronutrients for improving soil fertility, health, and soybean yield. Sustainability13:11766. doi: 10.3390/su132111766

  • CrossRef
  • Google Scholar

• 25

  ToishimanovM.SuleimenovaZ.MyrzabayevaN.DossimovaZ.ShokanA.KenenbayevS.et al. (2024). Effects of organic fertilizers on the quality, yield, and fatty acids of maize and soybean in Southeast Kazakhstan. Sustainability16:162.

  • Google Scholar

• 26

  Trujillo-TapiaM. N.Ramírez-FuentesE. (2016). Bio-fertilizer: an alternative to reduce chemical fertilizer in agriculture. J. Global Agric. Ecol.4, 99–103.

  • Google Scholar

• 27

  Wijerathna-YapaA.PathiranaR. (2022). Sustainable agro-food systems for addressing climate change and food security. Agriculture12, 1554–1564. doi: 10.3390/agriculture12101554

  • CrossRef
  • Google Scholar

• 28

  YakimenkoM. V.BegounS. A.SorokinaA. I. (2016). Compatibility of collection strains of soybean rhizobia with fungicides and growth-promoting drugs. Far East. Agrar. Bull.2, 38–41.

  • Google Scholar

• 29

  YerzhebayevaR.DidorenkoS.BastaubayevaS.AmangeldiyevaA.MaikotovB.KassenovR.et al. (2024). Soybean drought tolerance and escape: field trial assessment of yield, maturity groups and smooth-wrinkled seed coats in Kazakhstan. Agriculture14:1884. doi: 10.3390/agriculture14111884

  • CrossRef
  • Google Scholar