What is Biostimulants?
Biostimulants are substances or microorganisms that improve plant nutrition, nutrient efficiency, stress resistance and quality characteristics by stimulating natural processes within the plant, rather than directly providing nutrients or acting as pesticides. Common examples include protein hydrolysates, seaweed extracts and beneficial microorganisms, which are applied to seeds, foliage or soil to promote growth and yield, especially under abiotic stress conditions such as drought or extreme temperatures.
What are abiotic stresses?
Abiotic stresses are negative impacts on plants caused by non-living factors, such as extreme temperatures, drought, salinity, heavy metals, and high radiation. Abiotic stresses are detrimental to plant growth and development and contribute to global crop yield declines. While we cannot fully predict and protect plants from abiotic stresses, we can enhance their tolerance to these stresses through products such as biostimulants. To mitigate these adverse effects, biostimulants are increasingly being incorporated into agricultural systems to modify plant physiological processes and maximize productivity. As we work to address global hunger and achieve the United Nations Sustainable Development Goal of Zero Hunger, agricultural efficiency and sustainability are crucial. This means adapting agriculture to global warming, extreme weather events, reduced water resources during droughts, and the reclamation of marginal lands. Biostimulants play an important role in optimizing land use and increasing crop resilience.
Types of Biostimulants：
1. Protein Hydrolysates:
Amino acid biostimulants are produced through chemical and enzymatic methods, typically from the hydrolysis of proteins found in crop residues and animal manure. These essential amino acids and peptides are often referred to as the building blocks of proteins.
These amino acids play a crucial role in enhancing plant growth and resilience. When added to biostimulant formulations, they help improve nutrient uptake, stimulate root development, and enhance plant stress tolerance. This is particularly beneficial in agricultural environments, where plants are often exposed to abiotic stresses such as drought or salinity.
2. Humic and Fulvic Acids:
Humic and fulvic acid biostimulants are naturally formed in soil as organic matter decomposes. This is likely due to the decay of plant, animal, and microbial residues, as well as biochemical reactions by soil microorganisms such as bacteria and fungi.
These organic acids are crucial for plant biostimulants because they enhance nutrient availability and improve soil structure. By chelating essential nutrients, they promote better nutrient uptake by plants and stimulate the activity of beneficial microorganisms, thereby promoting a healthier soil ecosystem. This not only enhances crop resilience to disease and stress but also reduces the need for synthetic fertilizers, making agriculture more sustainable.
3. Seaweed Extracts and Botanicals:
Seaweed extracts and plant biostimulants have been used in agriculture for centuries, but their biostimulant properties have only recently been thoroughly studied. When applied to soil, seaweed can enhance water retention and promote overall soil health.
4. Chitosan and Other Biopolymers:
Chitosan is a plant biostimulant derived from the biopolymer chitin, a fibrous substance found in fungal cell walls. In agriculture, chitosan has been used to improve plant resilience to abiotic stresses, such as hot and cold weather.
5. Inorganic Compounds:
Inorganic elemental biostimulants, including silica, selenium, cobalt, sodium, and aluminum, can strengthen plant cell walls and promote growth when applied in appropriate amounts.
How biostimulants work？
ⅠDirect Effects on Plant Physiology
1. Regulating Endogenous Hormone Balance in Plants
Principle: Many biostimulants (such as seaweed extracts and certain amino acids) contain trace amounts of natural plant hormones (such as auxins, cytokinins, and gibberellins) or can stimulate the plant’s own synthesis of these hormones.
Effect: By regulating hormone balance, they precisely control plant growth and development. For example:
▷Promoting root development (auxin action): Forming more and longer root hairs and lateral roots, expanding the absorption area.
▷Promoting cell division and elongation (cytokinin and auxin action): Promoting plant growth.
▷Delaying aging (cytokinin action): Maintaining leaf greenness and prolonging photosynthesis.
2. Stimulating the plant’s defense system (inducing systemic resistance)
Principle: Certain biostimulants (such as chitosan, some seaweed extracts, and microbial secretions) are recognized by receptors on the plant surface and act as “warning signals” (elicitors).
Effect: Plants mistakenly believe an “enemy” is approaching and activate a complex defense mechanism, prematurely entering a state of “warfare.” This phenomenon is called systemic acquired resistance (SAR) or induced systemic resistance (ISR). Specifically, it manifests as:
▷Synthesis of antioxidant enzymes: Such as superoxide dismutase (SOD) and peroxidase (POD), which rapidly eliminate excess free radicals produced by stress (drought, high temperature, salt damage, etc.), reducing oxidative damage.
▷Synthesis of disease-resistant substances: Production of phytoalexins, phenolic compounds, and lignin, which strengthen cell walls and prevent pathogen invasion.
▷Synthesis of osmoregulatory substances: Accumulation of proline and betaine, which maintain cellular hydration and resist drought and salt stress.
3. Enhanced photosynthesis efficiency
Mechanism: By providing trace elements, regulating stomatal opening and closing, and increasing chlorophyll content.
Effect: Improves light energy utilization efficiency, generates more carbohydrates (sugars), and provides more “energy fuel” for plant growth, development, and stress resistance.
4. Improved Nutrient Assimilation and Transport
Principle: Amino acid biostimulants can serve as a readily available source of organic nitrogen and carbon skeletons.
Effect: Plants no longer need to expend significant energy converting inorganic nitrogen (such as nitrate) into amino acids, significantly saving energy. This saved energy can be used for other life activities, improving nutrient utilization efficiency. Furthermore, some biostimulants can promote long-distance nutrient transport within the plant.
II. Effects on the Soil and Rhizosphere Environment
1. Improved Soil Structure and Chemical Properties
Principle: Humic acid, fulvic acid, and other substances are excellent natural chelating agents and soil conditioners.
Effect:
▷Chelation: Encapsulates trace elements (such as iron, zinc, and manganese) that are immobilized in the soil and inaccessible to plants, forming a form that is easily absorbed by roots, thereby activating soil nutrients.
▷Improved Structure: Promotes the formation of soil aggregates, making the soil more loose, breathable, and able to retain water and nutrients.
2. Stimulate and enrich beneficial microorganisms
Principle: Biostimulants (especially humus) provide high-quality food (carbon source) for beneficial microorganisms in the soil.
Effects:
▷Promote microbial growth: Stimulates the proliferation of beneficial microorganisms such as phosphate-solubilizing bacteria, potassium-solubilizing bacteria, and nitrogen-fixing bacteria.
▷Enhancement: These microorganisms convert unavailable phosphorus and potassium in the soil into effective forms and fix nitrogen from the air, acting as an “external digestive organ” for plants, greatly improving fertilizer utilization.
3. Enhance rhizosphere metabolic activity
Principle: Biostimulants create a healthier rhizosphere microecological environment.
Effects: Roots and microorganisms experience more robust metabolic activity, secreting more organic acids, enzymes, and other substances, further activating soil nutrients around the rhizosphere.
The Difference Between Biostimulants and Traditional Fertilizers：
While both plant biostimulants and traditional fertilizers are designed to promote plant growth, they work in very different ways. Understanding the differences can help you decide when and how to use them for optimal crop health.
1. Function: Fertilizers primarily provide essential nutrients such as nitrogen, phosphorus, and potassium that plants need for growth. Their primary function is to directly nourish plants by replenishing nutrient levels in the soil. Biostimulants, on the other hand, do not directly provide nutrients. Instead, they enhance the plant’s ability to absorb and use them more efficiently, stimulating natural processes that promote growth, resilience, and productivity.
1. Focus on Plant Health: Fertilizers are nutrient-based, focusing on nourishing plants and ensuring they receive the nutrients they need for basic growth. Biostimulants take a broader approach, focusing on overall plant health, improving plant resilience, and enhancing plant responses to environmental conditions such as drought or extreme temperatures.
1. Impact on Soil Health: Fertilizers, especially synthetic fertilizers, can sometimes lead to soil degradation if not managed properly. Excessive use can lead to nutrient imbalances and damage soil microorganisms. Biostimulants can improve the microbial environment and promote beneficial biological activity, thereby maintaining long-term soil fertility and thus positively impacting soil health.
1. Regulation: Fertilizers are strictly regulated for their nutrient content and environmental impact. Biostimulants are generally less regulated and fall into a separate category. They are defined based on their role in enhancing internal plant growth processes rather than as a direct nutrient source.
1. Environmental Impact: Excessive fertilizer application can lead to runoff and pollution, exacerbating problems such as eutrophication. Biostimulants are an environmentally friendly solution that can reduce the need for excessive fertilization and minimize harmful environmental impacts.
In agriculture, by combining traditional fertilizers with biostimulants, growers can provide plants with the essential nutrients and biological support they need for growth, resulting in healthier crops and more sustainable agricultural practices.
Dora Solutions
At Dora, we leverage the latest technologies, including innovative plant biostimulants, to revolutionize agriculture and improve crop health. Our solutions are applied to a wide range of crops to maximize yield, improve crop quality, enhance nutrient utilization, and more. Learn more now!