Agriculture Reference
In-Depth Information
Table 2.1 (continued)
Nano-
content
Claims
a
Patent title
Ref.
Novel sustained-release
nanosized fertilizer and pro-
duction method thereof
Cross-listed with Category
1 ammonium salts
Lin (
2008
)
Zn
Zinc oxide suspension as
agricultural trace element
fertilizer
A zinc oxide powder mixed
with polymeric wetting
agents and cellulose-based
thickening agents is ground
down to the size of 100-
1,000 nm. When used as a
trace element fertilizer,
improved zinc supplementa-
tion is claimed. Could poten-
tially be cross-listed in
Category 2 as an additive to a
bulk fertilizer
He et al. (
2009
)
a
Description provided from patent information, however, there may not be evidence provided in
the patent to corroborate the claims
Silicon dioxide (silica) is one nanomaterial that has been generating attention in
both patents and research papers. Papers from Lin et al. have examined the effect of
nanostructured silica treatments on growth in spruce and larch tree seedlings (Lin
et al.
2004a
,
b
). They found that nanostructured silica forms a protective film at the
cell wall after absorption, which is thought to improve plant stress resistance. In
their studies, seedling roots were soaked in solutions of nanostructured silica,
although the size and morphology of the material were not described. At 500
L
of silica/L treatment, a statistically significant increase in height, main root length,
root diameter, and number of lateral roots was found. This treatment also led to
higher chlorophyll content than what was found in controls. Similar studies have
looked at the effect of silica nanoparticles on maize (Suriyaprabha et al.
2012
) and
tomato (Siddiqui and Al-Whaibi
2014
). Amorphous silica nanoparticles (20-40 nm
by TEM) were compared to bulk silica treatments on the growth of maize, and the
nano-treatment led to improved growth and greater silica accumulation. In the
study on tomato, average 12 nm silica nanoparticles were utilized; however, large
micron-sized particles are visible in the SEM images provided. Nevertheless, the
authors noted greater seed germination, seed vigor index, and weight. Silica
nanoparticles have also found their way into patented fertilizer formulations. For
example, a Korean patent by Kim incorporated colloidal silica in the size range of
5-60 nm in a bulk NPK fertilizer as an additive for promoting plant propagation and
increasing resistance to pathogenic bacteria (Kim
2007
). Nanosilica has also been
included in fertilizer treatments as a water and mineral adsorbent (Wei and Ji
2003
;
Zhang et al.
2005c
; Chen
2002
).
Nano-TiO
2
has been generating a considerable amount of research interest into its
use as a fertilizer additive due to its photoactivity. Several papers have investigated
the effect of nano-TiO
2
on spinach (Zheng et al.
2005
;Yangetal.
2007
). Spinach
μ
