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EXPERT BLOG
Of the micronutrients, Zn is, arguably, the most critical
for the society and environment. Zn deficiency in soil is
increasingly linked to human Zn deficiency...
for enhancing yield, but also to potentially minimize pesticides
and nitrogen fertilizer footprints in the environment.
The extent to which each micronutrient influences agronomic
outcomes is dependent on its concentration in soil, but in
general, the more lacking they are in soil, the greater the
response their addition evokes in the plant. As a quick fix,
individual micronutrients can be applied to crops to promptly
address specific deficiency symptoms. However, the strategic
use of micronutrients in fertilizers can be viewed in the
context of balanced fertilization, where macronutrients (N, P,
and K) form the basis of fertilization with the supplementation
of one or more micronutrients, to generate a comprehensive
fertilizer regime that addresses systems-level crop responses.
Such balanced fertilizer regimes should, of course, be based
on the results of soil and/or plant tissue testing to determine
nutrient levels and associated soil and crop needs.
This dual possibility is convenient because many of the root
biological processes requiring micronutrients to function, as
well as the transport mechanisms of micronutrients into the
plant cell, also happen in leaves.
Of the micronutrients, Zn is, arguably, the most critical for the
society and environment. Zn deficiency in soil is increasingly
linked to human Zn deficiency, which is a serious health
concern in many parts of the globe, especially in areas where
staple food crops grown in nutrient-poor soils form the major
diets. Little Zn is used in fertilizers in today’s agriculture,
compared to its use in other industries. Therefore, expanding
the Zn market beyond non-agro uses would promote its use in
agriculture more, allowing its full socio-environmental benefits
to be realized.
The relative effectiveness of each micronutrient is determined
by how it is packaged and delivered to plants. The most
common packaging methods are as oxides (particles) or
sulfates (salts). Oxide forms are typically cheaper than sulfates,
but are not as readily available to the plant. More recently,
packaging as nanomaterials using oxide particles that are
far smaller in size than regular oxides is being studied,
with positive effects observed in crops. Differences in crop
responses to packaged forms depend mainly on the rates of
dissolution and availability of the active nutrients.
However, regardless of how they are packaged, micronutrients
can be delivered to crops either via soil or foliar treatments.
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