Agriculture Reference
In-Depth Information
One major weakness in the current literature relating to nanotechnology in
fertilizers is the dearth of overall standardization in the field. For example, many
studies examining the effects of a particular nanofertilizer lack even the most basic
physical characterization of the formulation. Differences in size, monodispersity,
and surface chemistry can lead to dramatic physical and chemical changes in a
nanomaterial; this could lead to seemingly contradictory effects from the same type
of nanomaterial. At a minimum, basic physical characterization by microscopy
(SEM, TEM, or AFM) to confirm size and monodispersity should be required in all
nanofertilizer research. Furthermore, a standardization is required around the def-
inition of “nano.” Many formulations claiming to be “nano” are in fact more truly
on the submicron or micron scale. In order to move forward with credibility, it is
recommended that the universal definition of nanoscale (1-100 nm) be employed in
fertilizer applications. Our review also indicates gaps in information associated
with the patented products. For example, little information is available to indicate
whether the nanomaterials were added to leaves or soil, whether the data used for
registration was obtained from greenhouse or field studies, or from soil or soil-less
media. Rigorous science-based processes for product development and perfor-
mance evaluation are required to avoid misconstruing the real impact that nano-
technology may have in agriculture.
A major challenge for nanotechnology in fertilizer inputs and nanoscale coatings
or host materials is to help synchronize the release of the essential fertilizer
nutrients with the temporal and spatial demands by crops at the farm level. A
“smart” nanofertilizer should prevent the nutrients from prematurely interacting
with soil, water, and microorganisms and release nutrients only when they can be
directly internalized by the plant. Agrium
s Environmentally Smart Nitrogen (ESN)
product is a polymer-coated (non-nanotechnology-based) product that releases
nitrogen at changing rates depending on soil water and temperature (
www.
smartnitrogen.com
, accessed January 4, 2014). More sophisticated release systems
may require the incorporation of nanodevices, such as nanosensors, of chemical or
biological origin within the fertilizer. Polymer capsules built from nanoscale
polyelectrolyte layers have already been reported (Li et al.
2010
) that can be used
in triggered release systems for drug delivery (De Geest et al.
2007
) suggesting that
similar systems for fertilizer release may not be far behind. The incorporation of
molecular recognition agents such as antibodies (Jongeijk and Verheesen
2011
), or
aptamers (Mastronardi et al.
2014
; Sultan and DeRosa
2011
; Zhang et al.
2013
)to
aid in the specificity of the fertilizer nutrients, could be transformative in this
regard.
'
2.5 Conclusions
The goal of this chapter was to provide some insight into what impact nanotech-
nology might have on fertilizer inputs over the short- and long-term. The findings
presented here indicate that nanotechnology is already beginning to have an impact.
