«Did you know?» n°5

It’s no longer a secret, our agriculture system has to change, has to be more sustainable 🌾. As we are facing population growth, renewable options are a necessity in order to improve crop quality & yield and minimize environmental and human health impacts 🌍

  ♻️ Biostimulants and biofertilizers both promote plant growth and development, they are becoming a viable complement to mineral fertilizers and chemical products and represent an attractive business opportunity in agronomy and agro-industries.

➡️ What are biostimulants and biofertilizers exactly?

  👉 Biostimulants are defined as substances, algae or plant extracts, metabolites etc, enhancing the physiological processes of plants resulting in better absorption of nutrients, better stress tolerance.

  👉 Biofertilizers contain microorganisms (bacteria, fungi, microalgae) colonizing the rhizosphere of plants which increases absorption of nitrogen, phosphorus, potassium and minerals by plants.

➡️ Let’s now focus on algae:

Algae already proved to be very good candidates as both biofertilizers and biostimulants for a wide variety of edible plants 🌱 (onion, maize, papaya seedlings, cucumber, tomato plants, beet, pepper plants, lettuce, aubergine, etc), with effects similar or even better than common fertilizers according to several studies.

  ✅ Microalgae and macroalgae, whether in fresh or dried biomass form, as well as through their extracellular exudates, exhibit significant biostimulant properties when applied on leaves or introduced at the root level. This is due to their abundant nutrient content, including amino acids, phytohormones, protein hydrolysates, humic substances, polysaccharides, antioxidants, vitamins, and other beneficial compounds.

  ✅ The algae biomass can also be mixed with other naturel fertilizers to improve the nutrient supply. In addition, positive results were obtained for a mixed biomass of algae and bacteria 🦠 (co-culture of Nostoc + Azotobacter on lupine seeds 🪴, Chlorella + Bacillus on lettuce leaves 🥬, etc). 

Some positive demonstrated effects are:

  👉 Increase in: dry and fresh weight, root length, height and leaf number, global crop yield 

  👉 Improvement of: germination, leaf area, pigment content, accumulation of sodium and potassium in roots and shoots

  👉 Reduction of the negative effect of salt stress


For more details :

✏️ Kapoore R.V. et al., Algae biostimulants: A critical look at microalgal biostimulants for sustainable agricultural practices, Bio. Adv., 2021, doi:10.1016/j.biotechadv.2021.107754

✏️ Tantawy S.T.A., Atef N.M., Growth responses of Lupinus termis to some plant growth promoting cyanobacteria and bacteria as biofertilizers, J. of Food, Agr. and Env., 2010

✏️ Kholssi R. et al., Biofertilizing Effect of Chlorella sorokiniana Suspensions on Wheat Growth, J. of Plant Growth Reg., 2018, doi:10.1007/s00344-018-9879-7