South American scientific contribution to the biological products market

Given the growing challenges in agriculture, particularly concerning food security and environmental sustainability, the development and application of biological products have emerged as a promising soil management strategy. This biologically based approach aims to provide effective solutions to current agricultural challenges while minimizing the adverse environmental impacts associated with conventional practices. However, to fully capitalize on the potential of biological products and address emerging challenges, it is essential to overcome farmers’ resistance to adopting these products, strengthen relevant regulations, and optimize application practices.

An analysis of the most influential papers in the field reveals a significant contribution from South American authors (two from Argentina and one from Brazil), highlighting not only the region’s prominence in biological products research and regulation but also the importance of considering specific regional contexts, such as the continent’s vast agricultural landscapes, longstanding interest in sustainable practices, and supportive policy frameworks – when evaluating the efficacy and applicability of these products. Among the three most cited articles, the first is a comprehensive review that explores the benefits of bioinoculation in relation to key attributes such as initial growth, root development, and increased crop yields (Cassán and Diaz-Zorita, Reference Cassán and Diaz-Zorita2016). One of the highlighted results in this review is the commercial use of inoculants based on Azospirillum sp., which are applied to approximately 3.5 million hectares, primarily in cereal crops in South America (Cassán and Diaz-Zorita, Reference Cassán and Diaz-Zorita2016).

In the second most cited article (Domenech et al., Reference Domenech, Reddy and Kloepper2006), evidence was presented of a synergistic effect in promoting plant growth and enhancing resistance to pathogens (biocontrol) when using a combination of two biological products based on Bacillus subtilis and B. amyloliquefaciens. This combination enhanced resistance by up to 70%. Lastly, the third most cited article demonstrated the positive effect of bioinoculation with Bacillus subtilis on the emergence rate, growth, and nutrition of plants (Araujo, Reference Araujo2008). These Bacillus strains increase plant resistance through multiple mechanisms, including the production of antifungal antibiotics and the solubilization of nutrients such as phosphorus. In addition, certain strains, such as B. amyloliquefaciens and B. subtilis, have been shown to induce systemic resistance, helping plants to respond more effectively to soil-borne pathogens such as Fusarium and Rhizoctonia spp. The high scientific output from Brazil on this topic suggests that the country may be emerging as a leader not only in the consumption of biological products but also in the generation of knowledge and technology, something that is not common across many sectors of the economy. The development of the bio-input market could be strategically important in the recent context of rising prices for chemical fertilizers and petroleum-derived products.

The most frequent terms in the surveyed publications highlight the most commonly used and researched biological products: biological control products, with emphasis on wilts caused by the fungus Fusarium and insects (Hexapoda), as well as inoculants for legumes (especially soybeans), aimed at biological nitrogen fixation. Nonetheless, despite the considerable growth of the market, it is possible to identify a scarcity of publications that integrate biological products and their relationship with aspects beyond plant productivity and morphology.

The keyword co-occurrence map (Figure 4) reveals a fragmented landscape in biological products research, structured into distinct thematic clusters. The red cluster encompasses terms related to biocontrol and biopesticides (e.g., Trichoderma, Fusarium, biocontrol agent, and Hexapoda), reflecting a strong focus on pest and pathogen management. The green cluster includes terms such as rhizobiales, inoculation, and legume, associated with microbial inoculants used to promote plant growth, particularly via nitrogen fixation. The blue cluster, built around biological products, bacteria, chemistry, and microbiology, suggests a broader focus on microbial processes and their chemical interactions in soil systems.

These groupings are not arbitrary; they likely reflect how research projects, funding, and regulatory frameworks have historically approached biological products as tools with distinct and compartmentalized functions: either for plant protection, nutrient supply, or productivity enhancement. The limited overlap among clusters points to a lack of integrative studies that simultaneously address the biological, chemical, and physical dimensions of soil health. While biological products act as a central connector in the network, the surrounding clusters remain only loosely integrated.

This pattern raises important hypotheses. One possibility is that researchers and institutions tend to operate within disciplinary silos, plant pathology, microbiology, and agronomy, limiting cross-domain synthesis. Another is that methodological challenges or the absence of standardized indicators for soil health have discouraged more comprehensive assessments. Regardless of the cause, the result is a fragmented body of literature, where the multifunctionality of biological products is underexplored.

While the significant increase in the number of publications over the last 10 years is undeniable, this thematic fragmentation also reveals a critical limitation: the decline in studies that explicitly contribute to understanding soil health. Despite the central role of soil in sustainable agriculture, most publications remain concentrated on isolated effects, such as pest control or nutrient availability, rather than on integrated soil system functioning. Within the categories considered in the review, biocontrol products were the most frequently addressed biological products (51%), followed by biofertilizers (34%), further reinforcing the prevalence of targeted approaches over holistic evaluations.

Soil health and biological products: scientific basis

Most of these studies focus on evaluating the effectiveness of control over target species and on grain and fruit production, respectively. Only 2 of the 85 studies available after screening, or less than 3%, effectively assessed physical, chemical, and biological soil indicators, thereby limiting the results to the plant’s response to the biological product entering the system. Without holistic data, it’s challenging to confirm the long-term soil health benefits of these biological products. This gap hinders our ability to evaluate potential trade-offs, cumulative effects, or sustainability outcomes associated with repeated or large-scale applications. Despite the growing adoption and visibility of these inputs, there remains a lack of solid scientific foundation regarding the effects – whether beneficial or otherwise – of these products on overall soil health, both in the short and long term. It is worth noting, however, that there is a noticeable effort to evaluate the impact of biocontrol products on non-target organisms. These often include soil organisms, particularly arthropods, which can be considered an indicator of soil health (González-Núñez et al., Reference González-Núñez, Sandín-España, Mateos-Miranda, Cobos, De Cal, Sánchez-Ramos, Alonso-Prados and Larena2022; Temreshev et al., Reference Temreshev, Kopzhasarov, Beknazarova, Koigeldina and Dzhanbatyrov2023).

Some authors have observed a positive effect on plants and soil when using biocontrol products, resulting in reduced pest and disease pressure, increased productivity, and improved biological quality of the soil (Bourbos and Barbopoulou, Reference Bourbos and Barbopoulou2005; Frederic et al., Reference Frederic, Costa and Rocha2020; Hnoosh and Aljuaifari, Reference Hnoosh and Aljuaifari2020; Vörös and Ledóné, Reference Vörös and Ledóné2023). These biological products can improve soil biological quality by enhancing microbe–microbe interactions, stimulating induced systemic resistance in plants, and promoting nutrient cycling through microbial activity. Leles et al. (Reference Leles, Genta, Marques, Tessmann and Roberto2022) conducted a study that demonstrated the effectiveness of using biofungicides alone for controlling fungi responsible for grape rot, achieving a control rate of up to 51.5%. Additionally, by combining these biofungicides with chemical control, it was possible to achieve a control efficiency of 100%. These results were also observed in crops of significant economic importance, such as corn (Vörös and Ledóné, Reference Vörös and Ledóné2023), as well as in soybean and wheat, where integrated approaches enhanced disease suppression and yield (Borah et al., Reference Borah, Routhu, Saikia, Saikia, Bhamra, Nath, Singh, Rajpal and Navi2023; Kashyap et al., Reference Kashyap, Kumar, Khanna, Jasrotia and Singh2025).

Furthermore, there are studies highlighting the versatility of a single biological product as a biological control agent for various pests, diseases, and crops. This is evidenced by Grishechkina (Reference Grishechkina2015), whose research evaluated the action spectrum of a biological product and demonstrated its effectiveness both as an insecticide and as an antifungal against various pests and pathogens. The efficiency percentage ranged from 42% to 100%, demonstrating the broad range of action of this product with minimal environmental impact. Conversely, some studies observed effects on non-target organisms (Temreshev et al., 2022), indicating that some biocontrol products may not be entirely selective. Rigorous field trials and multi-season evaluations are essential to identify potential unintended impacts of these products on soil biodiversity. With the advancement of research, biological products, which have a lower environmental impact compared to synthetic ones, should become even more selective with reduced disturbance to ecological balance. To achieve this, it is important to evaluate additional indicators beyond plant response and the effects on the target pest population.

There is a wide diversity of biofertilizers evaluated, with most being growth-promoting bacteria, followed by organic fertilizers, accelerators of residue decomposition (Ivenin et al., Reference Ivenin, Bogomolova, Sakov, Popkova and Sergi2022; Sviridova et al., Reference Sviridova, Vorobyov, Andronov, Kurchak, Chizhevskaya, Pukhalskiy, Pishchik, Loskutov and Sitnov2022), and only one study involving probiotics (Bazar et al., Reference Bazar, Pemmineti and Mohammad2022). Biofertilizers can be used for production purposes (e.g., Jadhav et al., Reference Jadhav, Bhale and Paslawar2023; Płaza et al., Reference Płaza, Rzążewska and Gąsiorowska2021) and bioremediation (e.g., Chetverikov and Sharipov, Reference Chetverikov and Sharipov2022; Ryazanova and Fedorova, Reference Ryazanova and Fedorova2020). In this review, inoculants are considered biofertilizers that are applied to seeds. In this context, most studies refer to nitrogen-fixing bacteria, but also to bacteria that solubilize other nutrients, such as phosphorus and micronutrients (Adoko et al., Reference Adoko, Noumavo, Agbodjato, Amogou, Salami, Aguégué, Ahoyo, Adjanohoun and Baba-Moussa2022; Horodyska et al., Reference Horodyska, Pigat and Wonik2021).

The only two articles that evaluated all three dimensions of soil health (chemical, physical, and biological) focus on biofertilizers. Scharenbroch and Watson (Reference Scharenbroch and Watson2014) assessed four biofertilizers for urban forestry, including three organic fertilizers and one commercial product with growth-promoting microorganisms. They analysed, in addition to plant growth, eight soil indicators: density and moisture (physical indicators); pH, total nitrogen, available phosphorus, and exchangeable potassium (chemical indicators); and soil organic matter and microbial respiration (biological indicators). The authors concluded that, overall, the organic compost and the wood chip-based fertilizer had the best effects on soil health.

Jadhav et al. (Reference Jadhav, Bhale and Paslawar2023) evaluated seven types of biofertilizers (organic fertilizers) for organic cotton production and analysed, in addition to plant responses, 10 soil indicators. They found that, over the two years of evaluation, there was no significant difference in the physical properties, but the chemical and biological indicators generally improved. These findings suggest that biofertilizers can improve soil health by enhancing chemical and biological properties. Therefore, incorporating such products into soil management practices, particularly in organic or low-input systems, may be an effective strategy for promoting more sustainable and resilient agroecosystems.

It is evident that, in general, studies with biofertilizers analyse a greater number of soil indicators compared to studies with biocontrol products. The latter focuses solely on assessing off-target effects in the soil, which, as mentioned earlier, while it can be considered an evaluation of soil biological quality, is insufficient to be regarded as a comprehensive assessment of soil health. In studies on biofertilizers, it is more common to evaluate at least two dimensions, typically chemical and biological, because these products directly interact with soil microbial communities and nutrient availability, affecting both the biotic and abiotic components of the soil system (e.g., Ivenin et al., Reference Ivenin, Bogomolova, Sakov, Popkova and Sergi2022; Mustafayev et al., Reference Mustafayev, Tukenova, Alimzhanova, Ashimuly and Mustafayev2022).

However, studies related to bioinoculants follow the same approach found in biocontrol studies, focusing on the assessment of a specific group of indicators, usually chemical, with an emphasis on increasing productivity. Chernikova et al. (Reference Chernikova, Mazhaysky, Buryak, Seregina and Ampleeva2021) investigated the effects of using bio-stimulants in seed treatment, demonstrating that liquid bioinoculants contribute to improved performance in different soil types. Similar results were observed by Araujo (Reference Araujo2008), who found improvements in plant emergence and development, as well as higher levels of phosphorus and nitrogen concentration in the leaves, when bioinoculants were used across various crops.

Studies addressing the use of bioinoculants often reveal a correlation between the chemical and biological aspects of soil, even if the authors do not discuss this relationship. Physical indicators are often undervalued in the context of biological products, which reduces the opportunities for a comprehensive assessment of soil health through an index. This review shows that none of the biological product categories analysed have been the subject of studies assessing soil health considering all three pillars of indicators (i.e., physical, chemical, and biological), as most research has predominantly focused on yield. This lack of correlation between attributes and yield represents an opportunity for future studies with biological products.

Although not explicitly mentioned in the studies, as very few actually assessed soil health in the strict sense, it is important to highlight that the results obtained may be directly related to soil health and the potential improvements caused by the incorporation of the respective inputs into the system. The positive responses observed in biological products (primarily biocontrol) can be attributed to the stimulation of soil microbiota, which plays a crucial role in plant defence against diseases and other stresses.

By appropriately stimulating this population, biological products have the potential to enhance productivity. A balanced soil biological community plays a key role in supporting plant development by regulating enzymatic activity, enhancing nutrient cycling, and influencing soil physical and chemical properties. Microbial groups such as bacteria, fungi, and archaea contribute to essential soil functions, including organic matter decomposition, nitrogen fixation, and disease suppression (Bünemann et al., Reference Bünemann, Bongiorno, Bai, Creamer, De Deyn, de Goede and Brussaard2018). In recent years, the growing number of publications focusing on plant–microbiome interactions and biological products reflects increased scientific and commercial interest. This trend highlights the growing potential of biological products in leveraging plant–microbiome interactions for improved soil health. In particular, combinations of microorganisms have shown synergistic effects, improving nutrient availability, enhancing stress tolerance, and suppressing pathogens, thereby contributing to a more resilient and productive soil environment.