Agriculture Reference
In-Depth Information
Table 1. Essential plant nutrients
Number
Nutrient
Form absorbed by
plants
Average concentration in
plant shoot dry matter
Structural nutrients
1
Carbon (C)
CO
2
44.0%
2
Oxygen (O)
O
2
44.0%
3
Hydrogen (H)
H
2
O
6.0%
Primary major nutrients
4
Nitrogen (N)
NO
3
-
, NH
4
+
1.5%
5
Potassium (K)
K
+
1.0%
H
2
PO
4
-
, HPO
4
-2
6
Phosphorus (P)
0.2%
Secondary major nutrients
7
Calcium (Ca)
Ca
+2
0.5%
Mg
+2
8
Magnesium (Mg)
0.2%
9
Sulfur (s)
SO
4
-2
0.1%
Micronutrients or trace minerals
Fe
+2
, Fe
+3
100 ppm (mg kg
-1
)
10
Iron (Fe)
11
Manganese (Mn)
Mn
+2
50 ppm
12
Boron (B)
H
2
BO
3
-
20 ppm
Zn
+2
13
Zinc (Zn)
20 ppm
14
Copper (Cu)
Cu
+2
6 ppm
15
Molybdenum (Mo)
MoO
4
-2
0.1 ppm
Cl
-
16
Chlorine (Cl)
0.2%
Beneficial element
Ni
+2
17
Nickel (Ni)
0.5 ppm
18
Selenium (Se)
SeO
4
-2
, SeO
3
-2
Trace
19
Vanadium (V)
VO
3
-
, VO
+2
Trace
Na
+
20
Sodium (Na)
Trace
21
Silicon (Si)
Si(OH)
4
0.1%
22
Cobalt (Co)
Co
+2
Trace
Al
+3
23
Aluminum (Al)
20 ppm
The nature of plants makes them vulnerable to a wide range of natural environmental
insults
,
both biotic and abiotic, in addition to an increasing number of anthropogenic factors,
including pesticides and pollutants. However, with the continuous improvement of agriculture
technology, especially the application of chemical fertilizers, crop yields have greatly
increased in the past sixty years (Fan et al., 2012). Recent research on nanoparticles in a
number of crops has found enhanced germination and seedling growth, photosynthetic
activity, nitrogen metabolism, mRNA expression, and protein levels, as well as positive
changes in gene expression; these observations clearly indicate the potential use of
nanoparticles for crop improvement (Kole et al., 2013). Nanoparticles are defined as particles
with at least two dimensions below 100 nm (i.e., 0.1 µm). They are generated during
combustion processes and diverse, naturally occurring abiotic and biotic chemical processes.
Their commercial production has increased steadily because they are used in many novel
applications such as catalysts, semiconductors, drug carriers, and cosmetics; the development
of additional novel materials is likely (Dietz and Herth, 2011). Food and agricultural
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