What is an agricultural biostimulant?
Biostimulants are micro-organisms or substances that articulate physiological and biochemical processes in plants. They act through different mechanisms than fertilisers and plant protection products. Biostimulants are complementary to crop nutrition and protection.
Biostimulants are applied to maximise the genetic potential of the plant, causing changes in hormonal status, activating metabolic processes, improving nutritional efficiency, stimulating development and improving the response to abiotic stress.
When to apply biostimulants?
They can be applied via foliar or in the irrigation system. Applications should be made early in the day or in the evening, to facilitate foliar absorption, and the doses to be applied vary according to the product, crop, damage or environment.
How are biostimulants classified?
Biostimulants are classified as follows:
- Humic and fulvic acids. Humic substances are natural constituents of soil organic matter, resulting from the decomposition of plants, animals and micro-organisms, but also from the metabolic activity of soil micro-organisms that use these compounds as a substrate.
- Amino acids and peptide mixtures. These are obtained by chemical or enzymatic hydrolysis of proteins from agro-industrial plant and animal products.
- Algae and plant extracts. The use of algae as a source of organic matter and fertiliser is very old in agriculture, but the biostimulant effect has only recently been detected.
- Chitosans and other biopolymers. Chitosan is the deacetylated form of the naturally or industrially produced biopolymer chitin. Polymers/oligomers of various sizes are commonly used in cosmetics, medicine, food and agriculture.
- Inorganic compounds. Chemical elements that promote plant growth and may be essential for some but not all species are often referred to as “beneficial elements”.
- Beneficial fungi. Fungi interact with plants in many ways, from mutualistic symbiosis to parasitism. There is growing interest in the use of mycorrhizal fungi to promote sustainable agriculture.