Water availability is one of the main limiting factors in modern agriculture. As drought events become more frequent, solutions that enhance plant resilience are increasingly necessary. Bio-stimulants are emerging as strategic tools to support crop performance under adverse conditions.

To investigate this challenge, Neoalgae commissioned a controlled-environment study at the CSIC research chamber, conducted by Marta Laguna from the company Agroot, to evaluate the effect of several Spiragro products on Lactuca sativa var. Maravilla under defined water stress.

This article presents the key findings and their agronomic interpretation.

Experimental design

Water regimes:

  • Non-stressed control: 100 % field capacity (FC)
  • Water-stressed treatment: 70 % FC

Duration:

  • 35 days after transplanting

Treatments tested:

  • Control 100 % FC
  • Control 70 % FC
  • Two commercial comparators
  • Spiragro Engorde
  • Spiragro Premium
  • Spiragro Chlorella (new development)
  • Spiragro Protect B

Parameters measured:

  • Shoot and root biomass
  • Photosynthetic pigments
  • MDA (oxidative stress)
  • SPAD index

Main results

1. Biomass

Water stress reduced growth, but Spiragro products mitigated the effect:

Engorde

  • +5.9 % shoot biomass
  • +27.6 % root biomass

Protect B

  • +2.5 % shoot biomass
  • +25.1 % root biomass

Premium

  • +4.9 % shoot biomass

Chlorella

  • +2.7 % shoot biomass

Partial conclusion: Engorde and Protect B substantially improved root development.

2. Photosynthetic pigments

Chlorophyll a was highly sensitive to stress.

  • Protect B: highest chlorophyll a levels, surpassing the non-stressed control
  • Premium: strong recovery
  • Engorde and Chlorella: moderate but consistent improvements

Carotenoids increased in all Spiragro treatments.

3. Oxidative stress (MDA)

One of the strongest outcomes:

  • Protect B recorded the lowest MDA values
  • Engorde also showed notable reductions

Lower MDA = less cellular stress.

4. SPAD index

Across all measurements:

  • Chlorella and Protect B maintained the highest SPAD levels
  • Premium showed intermediate-high values
  • Engorde displayed moderate improvements

Higher SPAD = greater photosynthetic stability.

General interpretation

Spiragro products delivered:

  • Improved physiological stability
  • Reduced oxidative stress
  • Stronger root systems

Engorde and Protect B offered the most solid overall impact.

Agronomic and economic projection

Estimated benefits:

  • +164 to +379 kg/ha shoot biomass
  • +130 to +300 €/ha added value
  • Application cost: 12 L/ha
  • ROI: 20 % – 177 %

Field validation is still required.

Impress Project

Theses studies have been done thanks to Impress Project.

Conclusions

The study conducted by Marta Laguna (Agroot) demonstrates that Spiragro bio-stimulants, particularly Engorde and Protect B, significantly enhance lettuce resilience under water stress by improving:

  • root growth
  • photosynthetic pigmentation
  • physiological stability
  • protection against oxidative damage

These conclusions reinforce the role of Spiragro as a tool for more water-efficient, resilient and sustainable agriculture, supported by independent external research under controlled conditions.