What biofertilizers are and how they work

Soil fertility has become one of the major challenges of modern agriculture. The need to produce more, with fewer resources and lower environmental impact, has revealed a reality that many growers already recognise: chemical fertilisation alone no longer guarantees balanced soils or resilient crops. The loss of organic matter, compaction and low microbial activity limit the real availability of nutrients and reduce productive potential, even in well‑managed farms. It is precisely in this context that biofertilisers become essential: they not only correct symptoms but act at the root of the problem — soil biology.

Producers feel, day by day, that the soil no longer responds as it used to. If you observe persistent chlorosis, irregular growth or increasingly compacted soils, you are facing clear signs that the soil needs a different approach. The solution? Biofertilisers have been developed specifically to address these challenges, restoring life to the soil and stability to crops.

In this article, we explain how they work, what types exist, what results they show in the field and how to integrate them into a more efficient and sustainable fertilisation programme. It is a guide designed for those seeking to improve productivity without compromising soil balance.

Impact of biofertilisers on soil

Before understanding how they work, it is essential to recognise the impact they have on the soil. Biofertilisers act on processes that are invisible to the naked eye but decisive for productivity:

• Increase microbial activity — beneficial microorganisms colonise the rhizosphere, compete with pathogens and stimulate natural regeneration processes
• Improve soil structure — greater aggregation, better infiltration and water retention, reducing compaction
• Increase nutrient availability — they solubilise phosphorus, fix nitrogen and mobilise essential micronutrients
• Strengthen root growth — deeper and denser roots, increasing tolerance to water and heat stress

Under favourable conditions, beneficial microbial populations can double in just 48 hours, accelerating the biological regeneration of the soil. This is why continuous application has cumulative effects: the more active the microbiology, the more efficient the fertilisation.

Understanding these impacts helps explain why biofertilisers are so effective. Next, we analyse the mechanisms that make these results possible.

How biofertilisers work

As with elicitors or biological pest control, biofertilisers do not rely on a single mechanism. They are an integrated system of processes that together improve soil fertility and plant resilience. Among these processes, four mechanisms are directly felt by growers in the field:

• Biological nitrogen fixation — Microorganisms such as Azospirillum, Rhizobium and Azotobacter convert atmospheric nitrogen into forms assimilable by plants. Trials show increases of 15–30% in nitrogen availability, reducing the need for chemical fertilisation and improving early crop vigour
• Phosphorus solubilisation — Solubilising bacteria release phosphorus bound in the soil, increasing its availability by 20–40%, especially in soils with high fixation. This process is crucial in crops with high phosphorus demand, such as fruiting vegetables, vineyards and orchards
• Stimulation of root growth — Biofertilisers produce natural auxins, cytokinins and gibberellins that promote deeper and denser roots. Treated crops show roots up to 25% longer, greater soil exploration and improved tolerance to water stress
• Improvement of soil structure — Microorganisms increase organic matter, aggregation and water retention. Treated soils show reduced compaction, better infiltration and greater structural stability, especially in horticultural and irrigated crops

These mechanisms explain why different types of biofertilisers have complementary functions — a topic explored in the next section.

Types of biofertilisers

With so many mechanisms involved, it becomes essential to choose the right type of biofertiliser for each crop and stage of the cycle. Each type has its own characteristics, distinct origins and specific modes of action, allowing growers to select the most suitable solution according to crop needs and soil conditions. The diversity of available formulations enables more precise, efficient and sustainable strategies, integrating microbiology, natural compounds, algae extracts and enzymes that work together to enhance plant performance.

The table below summarises the main types of biofertilisers used in modern agriculture, making it easier to choose the most suitable solutions for each fertilisation programme.

Next, we show how these different types translate into real results in the field.

Practical examples in the field

The application of different types of biofertilisers results in concrete outcomes in the field, adjusted to the needs of each crop. The combined action of these products improves nutrient availability, strengthens soil structure and increases plant tolerance to stress, enabling consistent and measurable responses throughout the production cycle. The following examples illustrate how they work in practice and some of the observable results in different agricultural systems.

These results show that biofertilizers are not just a trend but a structural shift in how crops are nourished.

Recommended integrated program

To ensure that field results remain consistent season after season, it is essential to integrate biofertilizers into a structured program. An effective program combines biofertilizers, good cultural practices, and continuous monitoring::

• Assess the soil — identify phosphorus limitations, organic matter levels, and microbial activity
• Apply biofertilizers preventively — before root growth peaks
• Reinforce applications during critical stages — transplanting, flowering, and fruit set
• Integrate organic compounds — improve structure and water retention
• Maintain active microbiology — avoid incompatible chemicals
• Monitor vigor and root development — adjust doses according to crop response

As with biological pest control, prevention is key: when intervention starts early, results are more consistent and sustainable.

Advantages of biofertilizers

The adoption of biofertilizers provides direct and measurable benefits for the soil and for crops, as they:

• Reduce dependence on chemical fertilization
• Improve soil structure and soil health
• Increase nutrient uptake efficiency
• Enhance plant resilience
• Are suitable for organic farming
• Present no toxicological risks
• Contribute to higher final production quality

Considering these advantages, choosing biofertilizers is not only an environmental decision — it is a strategy with direct impact on productivity and the sustainability of your business.

Biofertilizers are now one of the most effective and sustainable tools to improve soil productivity and health. The combination of beneficial microorganisms, natural compounds, and good cultural practices enables consistent results, season after season.

At BIOSANI, you will find microbial biofertilizers, organic formulations, and elicitor‑type biostimulants tailored to the needs of each of your crops. Consult our catalogue or contact us for personalized technical guidance.