To improve plant growth, people have been adding ash or other forms of minerals to soils for more than 2000 years. However, current definitions of ‘essential‘ or ’beneficial‘ elements for plant growth rely on old and narrowly defined criteria that do not fully represent sustainable plant nutrition. These outdated definitions also compromise fertilizer regulation and practice.
In this paper, the authors review the origins and evolution of the currently used definitions. They then discuss some of the specific shortcomings, illustrating how modern scientific understanding has not been captured properly in scientific definitions as well as fertilizer regulations. For example, certain mineral elements, such as Na, Si, Se, Al, Co or I, are known to beneficially impact plant growth, while they are relegated to a legal and practical ‘no man’s land’ that by and large does not support their use as fertilizers.
The authors propose a new definition for ‘plant nutrients’: “A mineral plant nutrient is an element which is needed for plant growth and development or for the quality attributes of the harvested product of a given plant species, grown in its natural or cultivated environment.” This reframed definition explicitly includes both the essential and the demonstrated beneficial mineral elements to provide greater clarity.
It is further meant to enable regulators to consider the beneficial elements as legitimate fertilizer components while encouraging more scientific and commercial inquiry for optimizing yield and quality-oriented plant production strategies in different crops and environments. An open scientific debate to refine and implement this updated definition of plant nutrients is proposed, including an independent scientific body to regularly review the list of essential and beneficial elements. The debate could also attempt to refine the definition of plant nutrients to better align with nutrients deemed essential for animal and human nutrition, thus following a more holistic ’one nutrition‘ concept.
2 Responses
What about the elements which improve the soil conducive to plant growth or produce quality?
Mineral elements that have no proven physiological role in growth or quality of the plant would not be considered plant nutrients according to the proposed definition. If certain elements improve soil conditions and that results in increased availability of plant nutrients, the benefit for the plant may be there, but through these plant nutrients, not other elements.