The answer to this question lies in the meaning of the word ‘stimulate’. The Cambridge English dictionary defines the term as “to encourage something to grow, develop or become active”. By contrast, nutrients are the various chemical building blocks necessary for a plant or animal to manifest the physical evidence of growth, development and the many activities associated with life. When you add to the soil, it provides nutrients. Materials that increase the uptake or efficiency of those nutrients are considered fertilizers to be plant biostimulants.
Unlike the essential botanical macronutrients, nitrogen, phosphorus and potassium, contained in commercial fertilizers, only comparatively small quantities of these materials are required. Although some may have nutrient properties, these are secondary to their intended role. In practice, their primary purpose is to enhance or expedite a plant’s nutritional processes rather than acting as an additional source of nutrients. However, like animals, plants are frequently exposed to various forms of stress. It is termed ‘abiotic stress’ when its origin is physical rather than biological. Applying suitable plant biostimulants can also help them cope when exposed to stressful conditions.
Abiotic stress can take various forms. For example, drought is becoming increasingly frequent in South Africa. Also, in coastal regions, soil salinity is often high. Other physical factors that can impede a crop’s development include extreme temperatures, excessive dampness, insect pest and a long list of crippling crop diseases.
So, what sort of materials can alleviate these problems and enhance crop growth? In practice, many materials display these valuable properties. However, agriculturists generally divide these into two main categories when classifying plant biostimulants. They are either organic substances or microorganisms.
Regardless of the type, their actions closely parallel those of the vitamins and dietary supplements favoured by many health-conscious humans. As a matter of fact, ascorbic acid or vitamin C extracted from citrus fruits is a common ingredient used in these products. Other sources of suitable organic compounds include algae, animal tissues and fruit and vegetable waste. The raw materials undergo enzymatic hydrolysis during the manufacturing process to form protein hydrolysates. These contain amino acids, peptides and other compounds, the active ingredients of commercial plant biostimulants.
The second group of materials comprises various bacteria, non-pathogenic fungi and nematodes. The latter are tiny multicellular insects with non-segmented bodies that act as natural pesticides, avoiding the need to apply toxic chemicals. As biological entities, it is the by-products of their metabolism that benefit plant growth and health.
Kynoch, an acknowledged leader in plant nutrition and welfare, has developed two products to combat abiotic stress and boost plant physiology. You are welcome to download more information about our world-class KynoHumate-Black™ and KynoFulvate-Yellow™.