In this subject area, we discuss:
- How to secure nutrient supply, i.e.,
ensure that the plant's nutrient demand is met during
growth, and
- How to correct an (existing) undesirable
nutritional status, i.e., overcome deficiency or excess
situations.
In all measures, it must be considered that an abnormal nutritional state in a plant
fundamentally
signifies the absence or excess of a nutrient within the plant itself. This, however, does not mean
that this nutrient is absent in the plant's environment. It rather means that:
- The nutrient is either not present
or not chemically available (not in solution),
- It is present but has not reached
the plant, or
- It has reached the plant but has
not become functional within it.
Therefore, it seems logical to distinguish between indirect measures and direct measures
for
improving/securing nutrient availability.
Indirect measures do not directly add nutrients to the medium that "feeds"
the root but do improves
the conditions of nutrient uptake by changing the conditions in the root zone. Therefore, these
measures are aiming at reducing yield losses rather than directly increasing yield.
Direct measures are associated with addition the addition of fertilizers. The aim
is to improve
nutrient availability directly and initiate a yield increase by optimizing the physiological functions
that depend upon nutrients. However, the physiological functions depend on the growth factors anf
the genetics of the plant as these influence plant yield and quality. Even the best plant nutrition
cannot surpass these limits.
