Almond cultivation has become a strategic and profitable crop in the semi-arid regions of southeastern Spain. Its resilience in harsh soil and climate conditions has allowed its expansion even into marginal lands. However, this growth comes with challenges: farming on sloped terrains with degraded soils and low organic matter leads to problems like erosion, nutrient deficiency, and increased vulnerability of root systems to stress and imbalances.
Traditionally, almond production in these areas has relied heavily on mineral fertilization, mainly nitrogen and phosphorus. While this approach has delivered acceptable yields, it also presents major limitations: low nutrient uptake efficiency, salt accumulation, soil structure degradation, and growing dependence on costly chemical inputs.
To validate a more efficient and sustainable alternative, Probelte carried out a technical trial on a commercial almond farm (Lauranne variety) located in Hellín (Albacete), aiming to compare the effect of the biofertilizer Bulhnova with conventional fertilization. The goal was to demonstrate that Bulhnova could reduce the need for chemical fertilizers without compromising yield, while also enhancing soil biodiversity and crop profitability.
Bulhnova, developed by Probelte, is a microbial biofertilizer formulated with exclusive strains of Azospirillum brasilense (M3) and Pantoea dispersa (C3). These bacteria act directly in the rhizosphere, forming beneficial associations with the plant. They fix atmospheric nitrogen, solubilize phosphorus and other essential nutrients, and stimulate beneficial soil microbiota, increasing biodiversity and improving nutrient efficiency. This biological activity also contributes to long-term improvements in soil structure and helps crops cope with abiotic stress conditions.
Trial design and methodology
Objective: Reduction in conventional fertilizer input while maintaining yield.
| Parameter | Details |
|---|---|
| Location | Hellín, Albacete (Spain) |
| Crop & variety | Almond, cv. Lauranne |
| Farming system | Intensive, drip irrigation |
| Soil type | Sandy clay |
| Trial period | April – October |
| Evaluations | Yield, soil and foliar analysis |
Fertilization strategies compared
a. Conventional control treatment
- 100% mineral fertilization via fertigation
- Product used: Complex NPK 9-3-8, applied at 530 kg/ha
b. Bulhnova treatment
- Partial replacement of mineral fertilization (-40.0% approximately).
- Complex NPK reduced to 318 kg/ha, maintaining a lower contribution of NPK.
- Applied Bulhnova at 2 L/ha on three occasions (total: 6 L/ha per season)
Note: Both treatments received a common base fertilization of 15N–0P–0K + 40 SO₃ at 62 kg/ha
Key results
1. Reduction in mineral fertilizer us
Bulhnova enabled a 40% reduction in mineral NPK inputs without yield loss:
| Nutrient | UF in the Control plot | UF in the Bulhnova treated plot | Reduction (%) |
|---|---|---|---|
| N | 47.7 kg/ha | 28.6 kg/ha | -40.0% |
| P₂O₅ | 15.9 kg/ha | 9.5 kg/ha | -40.3% |
| K₂O | 42.4 kg/ha | 25.4 kg/ha | -40.1% |
2. Yield and vigor: +16.6% increase with Bulhnova
- Conventional (mineral): 2,520 kg/ha
- Bulhnova treatment: 2,940 kg/ha
Bulhnova-treated trees showed more balanced, vigorous, and uniform vegetative growth, reflecting improved root activity and nutrient use efficiency.
3. Soil fertility improvement
Soil analyses revealed a clear increase in total nitrogen, available phosphorus, calcium, and magnesium in Bulhnova-treated plots compared to the control.
These gains are directly linked to the activity of the microbial strains in Bulhnova, which improve nutrient availability and movement in the soil while also enhancing biological activity and water/nutrient retention—critical for long-term soil resilience.
4. Enhanced foliar nutrition
| Nutrient | Control (%) | Bulhnova (%) | Increase (%) | Technical insight |
|---|---|---|---|---|
| N | 1.84 | 2.15 | +17% | Supports strong vegetative growth |
| P | 0.19 | 0.24 | +26% | Key for flowering and fruit set |
| K | 1.05 | 1.12 | +7% | Enhances fruit filling and water balance |
| Ca | 1.20 | 1.42 | +18% | Improves fruit firmness and cell structure |
| Mg | 0.28 | 0.34 | +21% | Vital for photosynthesis and energy transfer |
Bulhnova clearly enhanced the uptake of critical nutrients during the most sensitive phases of crop development.
Economic performance and ROI
The application of Bulhnova proved to be an economically advantageous strategy compared to the exclusive use of mineral fertilizers.
- Reduction in the use of chemical inputs while achieving an increase in production.
- Improves soil fertility, leading to less degradation and a more sustainable structure in the medium and long term.
This translated into higher profitability per hectare and greater resilience in the production system, with the added benefit of reducing environmental impact.
Conclusions
The use of Bulhnova significantly reduces dependence on mineral fertilizers while improving productivity, soil health, and the profitability of almond cultivation.
In today’s agriculture—where sustainability, input costs, and regulatory pressure on chemicals are intensifying—Bulhnova offers a powerful, science-backed alternative for advisors, cooperatives, and forward-thinking growers.
