Agricultural biological
- Also known as
- biologicals, ag biologicals, biological crop input
An agricultural biological is a crop input derived from living organisms or natural materials, such as beneficial microorganisms, plant extracts or fermentation products, used to improve plant nutrition, growth, stress tolerance or protection from pests and disease.
What is an agricultural biological?
Agricultural biologicals, often shortened to biologicals, are crop inputs whose active ingredients come from living organisms or natural materials rather than from chemical synthesis. They include beneficial bacteria and fungi, products of microbial fermentation, plant and seaweed extracts, and other naturally derived substances.
The term is an umbrella rather than a legal category. It groups products that do very different jobs, from supplying nitrogen to a crop to protecting it from disease, and that are regulated differently depending on what they claim to do.
The main categories
| Category | What it does | Examples |
|---|---|---|
| Biostimulants | Stimulate the plant’s own processes to improve nutrient uptake, nutrient efficiency, stress tolerance, quality or yield | Seaweed extracts, humic substances, some microbial products |
| Biofertilizers and inoculants | Contain living microorganisms that increase the availability of nutrients | Rhizobia for legumes, phosphate-solubilizing microbes |
| Biopesticides | Control pests, diseases or weeds | Microbial fungicides, insect pathogens, some plant extracts |
Many products sit across categories. A single microbial strain might improve nutrient availability and also suppress a soilborne disease, but how it is sold and regulated depends on the claims made for it. In the United States, a product that claims to control a pest is regulated as a pesticide by the Environmental Protection Agency.
How biologicals work
Biologicals act through the plant, the soil, or both:
- Nutrient supply and availability. Some microorganisms fix nitrogen from the air through biological nitrogen fixation; others release phosphorus from soil minerals through phosphorus solubilization.
- Root growth. Some microbes and biostimulants promote root development, helping the plant explore more soil.
- Stress tolerance. Some products help crops maintain growth under abiotic stress such as heat or drought.
- Plant protection. Beneficial organisms can compete with pathogens, produce antimicrobial compounds, or trigger the plant’s own defenses.
- Colonizing the plant. Some beneficial microbes live on or in roots, including endophytes that live inside plant tissue.
How biologicals are applied
Biologicals are applied as a biological seed treatment, in furrow at planting, as a foliar application during the season, through irrigation by fertigation, or as a soil treatment. Products containing live organisms have practical requirements that chemical inputs do not: organisms must survive storage, handling and application, and some are sensitive to other products in the tank or on the seed.
Why growers use biologicals
Growers use biologicals to improve nutrient use efficiency, support yield under variable conditions, reduce reliance on some synthetic inputs, and build soil health. Results can vary with soil, weather and management more than those of many chemical inputs, which is why independent, replicated field trials matter when evaluating them.
Biologicals at Locus
Locus Agriculture develops biological crop inputs, including microbial seed and in-furrow treatments, soybean inoculants, a foliar biological and a biosurfactant soil conditioner, and describes selecting defined microbial strains as the basis of consistent field performance.
Frequently asked questions
Biological is the umbrella term for crop inputs from living organisms or natural materials. A biostimulant is one category within it: a product that stimulates the plant’s own processes to improve nutrition, stress tolerance or yield.
No. Many biologicals can be used in organic production, but organic certification depends on how a product is made and what it contains. A biological is not automatically approved for organic use, and some organic inputs are not biologicals.
Generally not entirely. Most biologicals are used alongside fertilizer to improve how efficiently nutrients are used. Legume inoculants are the clearest case of a biological substituting for nitrogen fertilizer, because the nitrogen-fixing bacteria they supply can meet much of a legume’s nitrogen need.
Sources
- Plant biostimulant definition, Agriculture Improvement Act of 2018, U.S. Congress
- Biopesticides, U.S. Environmental Protection Agency
- Plant biostimulants: definition, concept, main categories and regulation, P. du Jardin, Scientia Horticulturae, 2015