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Syromiatnykov

soybean (Glycine max) plants, particularly under abiotic inoculants supports multiple sustainability goals
stresses, such as drought, salinity, or degraded soils. simultaneously, making this biotechnology approach
For example, humic-acid-enriched inoculants have highly valuable in climate-smart and regenerative
improved shoot nitrogen levels and chlorophyll content agriculture systems.
in soybeans grown under water stress, outperforming Table 4 outlines the key environmental and agronomic
conventional inputs. 80-82 benefits of combining humic substances with nitrogen-
Furthermore, nutrient use efficiency—particularly fixing bacteria in soybean systems.
for nitrogen and iron—is improved due to the chelating This integration improves soil health, increasing soil
properties of humic substances and their influence on organic carbon by 15–20% through better humification
root architecture. These traits expand the absorptive and aggregation processes. 31,77 Nutrient use efficiency,
surface area and enhance mineral uptake. 83 particularly for nitrogen and iron, rises by 25–35% and
From a policy and certification standpoint, 20%, respectively, due to enhanced chelation and root
these biotechnologies align with organic farming development. 65,83
standards and are increasingly recognized under Regarding nitrogen loss reduction, the use of
eco-labeling frameworks, facilitating their adoption microbial inoculants with humics cuts nitrate leaching
in environmentally sensitive areas. As such, their and ammonia volatilization by up to 40%, helping
relevance extends beyond conventional agriculture and protect water and air quality. 78,79 Under abiotic stress
into regenerative and organic markets, where synthetic conditions, such as drought or salinity, co-application
inputs are minimized. 84 boosts yield by 25–30% and increases chlorophyll
Finally, by converting agro-industrial and municipal content, improving photosynthesis and resilience. 69,80,82
organic waste into humic biofertilizers, this approach This approach also enhances soil microbiota, increasing
contributes to circular economy goals—transforming rhizosphere biodiversity and sustaining beneficial
waste liabilities into agronomic assets. 85 bacterial populations across seasons. 32,42
As presented in Figure 4, the integrated application of From a climate and sustainability perspective,
nitrogen-fixing bacteria and humic substances provides it supports carbon sequestration and reduces
a spectrum of environmental and agronomic benefits in greenhouse gas emissions by lowering synthetic input
soybean cultivation. The most prominent contribution dependence. 25,31,85 Moreover, these practices comply
is to soil organic matter and structure, representing with organic farming standards and are eligible for
16.3% of the total assessed benefits. This is followed by eco-label certifications, making them valuable in
yield and protein increase (15.9%) and enhanced stress regenerative and circular agriculture models. 84,85
tolerance under conditions such as drought and salinity 6. Limitations, challenges, and future prospects
(15.4%). Reduction in nitrate leaching and nitrogen-
related emissions accounts for 14.5%, while nutrient use Mechanistic understanding of the interactions between
efficiency, particularly for nitrogen and iron, contributes humic substances and symbiotic microbes—particularly
13.6%. Contributions to the circular economy, such as nitrogen-fixing bacteria such as Bj —is improving,
waste valorization and policy alignment with organic yet considerable gaps remain. Recent studies suggest
certification standards, are notable as well, with 12.7% that humic compounds can modulate gene expression
and 11.8%, respectively. Figure 4 illustrates that the associated with nitrogen fixation and nodule formation.
combined use of humic substances and microbial However, these effects are strongly dependent on the

dosage and molecular form of the humic substances,
which necessitates precise formulation and extensive
field validation to ensure consistent agronomic
performance across environments. 77
Although humic substances may temporarily
suppress plant immune responses to enable microbial
colonization, this immunosuppression could also
reduce resistance to pathogens. Therefore, the trade-offs
Figure 4. Relative importance of environmental between enhanced symbiosis and disease vulnerability
and agronomic benefits from integrated bio-based must be carefully assessed in field conditions with
technologies in soybean cultivation varying biotic pressures. 77

Volume 22 Issue 6 (2025) 10 doi: 10.36922/AJWEP025230190