Bio-stimulants are substances of any form or microorganism that is applied to plants with the aim of improving nutrition effectiveness, abiotic tolerance to stress, and or crop quality irrespective of the amount of nutrients available. Biological fertilizers such as kelp extract and liquid fish fertilizers enhances nutrient supplies to plants. The mycorrhizal fungi and non mycorrhizal fungi, Rhizobium and Plant Growth-Promoting Rhizobacteria (PGPR) are microbial biostimulants. Therefore, microorganisms that are applied to plants may have dual physiological function as biological agents and as well as bio-stimulants.
Groups of Bio-stimulants In Agriculture
Bio-stimulants have been summarized by Kauffman et al. (2007), introducing its taxonomy and classification. They are available in different formulations and ingredients but are generally grouped into three categories according to their source and material composition. These groups include:
- Humic substances (HS)
- Hormone Containing Products (HCP)
- Amino Acids Containing Products (AACP)
Hormone containing products such as seaweed kelp extract contain a quantifiable amount of plant growth promoting hormones such as auxins, cytokinins, and gibberellins. In fact, "Bio stimulant" is described as any substance useful for plant growth and development other than pesticides, fertilizers or organic soil amendments. There are different categories of Bio-stimulants, which we discuss in detail. These include:
- Humic and fulvic acids
Humic substances are natural components in soil that are derived from the disintegration of animal, plant and microbial wastes but also from the metabolic activity of soil microorganisms using these substrates. Humic substances are heterogeneous compounds, originally classified according to their molecular weight and solubility into humins, humic and fulvic acid. These compounds also exhibit complex dynamics of associating or dissociating into supra-molecular colloids, and that is under the influence of plant roots through the release of protons and exudates. Humic substances and its complexes in the field come from interaction between organic matter, microbes and plant roots. The use of humic substances to promote plant growth and crop yields should optimize these interactions to achieve expected results.
- Protein hydrolysates and other compounds containing Nitrogen
Amino acids and peptide mixtures are obtained with chemicals and enzymatic hydrolysis of the protein from by-products of agro-industrial processes, from both plant origin (crop residues) and animal waste origin (e.g. epithelial tissue and collagen). Chemical synthesis can also be used alone or mixed with other compounds. Other nitrogen molecules include betaines, polyamine and "non-protein amino acids". Glycine-betaine is a good example of amino acid derivatives with anti-stress properties. These compounds play roles like acting as Bio-stimulants in plant development. Direct effects on plants include assimilation of Nitrogen, regulation of Enzymes involved in the assimilation of Nitrogen and its structural genes and signaling the acquisition of Nitrogen at the root. Amino acids play important roles as chelators. Proline, an amino acid, protects plants against heavy metals and contributes to the mobility and acquisition of micro nutrients.
- Botanical and Seaweed Extracts
The use of fresh algae as a source of organic matter and fertilizer with its Bio-stimulant effect have been recently registered. This leads to commercial use of algae extracts and purified compounds, which include polysaccharides, laminarin, alginates and carrageenans. Other ingredients that contribute to the plant growth improvement includes micro and macroorganisms, sterols, Nitrogen- containing mixes such as betaine and hormones. The majority of the algal (algae) species belongs to the brown algae phylum – Ascophyllum Nodosum, Fucus, Laminaria as the main genera but carrageenans takes its origin from red algae, which relates to a different phylogenetic line. Beneficial outcomes by the direct use of seaweed extracts by means of the soil micro-flora are likewise depicted, with the advancement of plant development advancing microbes and pathogen fighters in suppressive soils. Nevertheless cytokines, auxins, abscisic acid, gibberellic and other Hormone-like compounds, such as sterols and polyamines, have been identified in algae extracts to stimulate growth in plants.
- Chitosan and other biopolymers
Chitosan is a deacetylated type of the biopolymer known as chitin, manufactured organically or synthetically. Poly-and oligomers of measurable sizes are utilized in agricultural, medicinal, food and cosmetology. The physiological impacts of chitosan oligomersin plants are the after effects of the limit of this polycationic compound to bind an extensive variety of cell segments, including DNA, plasma membrane and cell wall components, yet additionally to bind particular receptors associated with initiating a defense gene, comparably as plant safeguard elicitors. Chitin and chitosan obviously utilize unique receptors and signaling channels.
- Beneficial microbes (fungi and bacteria)
Interaction occurs between the plant roots and the fungi in different ways, ranging from symbiosis (a mutually benefitting relationship between two or more organisms) to parasitism. The mycorrhizal fungi are a heterogeneous group of taxa that establish symbiosis with more than 90% of all plant species. Among the different forms physical interactions and taxa involved, arbuscular-forming mycorrhiza (AMF) are widespread species of endomycorrhiza associated with crops and horticultural plants where hyphae fungus from species of Glomeromycota penetrate into cortical roots and form branched structures called arbuscules. There is an increasing interest in using mycorrhiza to promote sustainable agriculture, the widely accepted advantages of symbiosis for nutritional efficiency (for macronutrients, especially for Phosphorus and micronutrients), protection of plants from abiotic and biotic stress, and water balance and retention.
Bacteria interact with plants in all possible ways: With reference to fungi, there is a continuum between mutualism and parasitism; Bacterial niches stretch from soil to within the cell in the root zone called the rhizosphere or rhizoplane. Both mycorrhiza and beneficial bacteria function in affecting plant life biogeochemical cycles, supplying nutrients, increased use of nutrients, induction of resistance to disease, improvement of abiotic compounds tolerant to stress, and modulation of morphogenesis by growth of plants regulators.
With all the evidence of the benefits that bio-stimulants provide, it’s easy to easy why they are superior to regular organic products, soil amendments, and fertilizers. That’s why at Alpha Nutrient, we created and formulated our products to be bio-stimulants. The products you can find to have bio-stimulating effects on your plants in our line up include:
- Omega Grow and Omega Bloom – a fish protein hydrolysate base that contains readily available N-P-K nutrients- that also contains natural hormones, enzymes, vitamins, fish oils, humic substances, and kelp. The NPK values are readily available, which means they will not require as much microbial digestion to make it available for plant uptake. This undoubtedly helps in growth and cuts down the amount of time required for growth.
- MycoRhize – our 12 species mycorrhizae inoculum blended with 35% kelp and 35% humic acids- both extremely powerful bio-stimulants, even more so when combined together.
- BioRhize – our bacillus strain soil microorganism inoculant that will protects roots against pathogens, increase nutrient availability, fix atmospheric nitrogen into plant available ammoniacal nitrogen, increase root growth, and decompose phosphite compounds into plant available phosphorus.
- FulBase – our revolutionary carbohydrate derived fulvic acid product made from renewable plant sources, with concentrated L-amino acids and fulvic content.
Try any of these products in your garden to see for yourself the power of harnessing bio-stimulants!
“About Biostimulants and the Benefits of Using Them.” European Biostimulants Industry Council, www.biostimulants.eu/about/what-are-biostimulants-benefits/.
Agricen. “Agricultural Biostimulants | Plant Health | Crop Production.” Plant Health Tech, www.agricen.com/agricultural-biostimulants.
“Athlete-Style Nutrition for a Plant: The Science of Biostimulants.” Alltech, ag.alltech.com/en/blog/athlete-style-nutrition-plant-science-biostimulants.
Brown, Patrick, and Sebastian Saa. “Biostimulants in Agriculture.” Frontiers in Plant Science, 2015.
“Plant Biostimulants: Definition, Concept, Main Categories and Regulation.” Egyptian Journal of Medical Human Genetics, Elsevier, 29 Oct. 2015, www.sciencedirect.com/science/article/pii/S0304423815301850.