Agriculture Reference
In-Depth Information
Considering the above facts about the role of nutrients in plant system, it
becomes quite evident that concentration of different nutrients in soil varies from
one location to the other, thus highlighting the need of fertilizers in agriculture.
4.4 Conventional Fertilizers Versus Nano-fertilizers
Conventional Fertilizers are generally applied on the crops by either spraying or
broadcasting. However, one of the major factors that decide the mode of application
is the final concentration of the fertilizers reaching to the plant. In practical
scenario, very less concentration (much below to minimum desired concentration)
reaches to the targeted site due to leaching of chemicals, drift, runoff, evaporation,
hydrolysis by soil moisture, and photolytic and microbial degradation. It has been
estimated that around 40-70 % of nitrogen, 80-90 % of phosphorus, and 50-90 %
of potassium content of applied fertilizers are lost in the environment and could not
reach the plant which causes sustainable and economic losses (Trenkel
1997
;
Omb
odi and Saigusa
2000
). These problems have initiated repeated use of fertilizer
and pesticide which adversely affects the inherent nutrient balance of the soil.
According to an estimate by International Fertilizer Industry Association, world
fertilizer consumption sharply rebounded in 2009-2010 and 2010-2011 with
growth rates of 5-6 % in both campaigns. World demand is projected to reach
192.8 Mt by 2016-2017 (Heffer and Prud
homme
2012
). But the large-scale use of
chemicals as fertilizers and pesticides has resulted in environmental pollution
affecting normal flora and fauna. Tilman et al. (
2002
) reported that excess use of
fertilizers and pesticide increases pathogen and pest resistance, reduces soil micro-
flora, diminishes nitrogen fixation, contributes to bioaccumulation of pesticides,
and destroys habitat for birds. Hence, it is very important to optimize the use of
chemical fertilization to fulfill the crop nutrient requirements and to minimize the
risk of environmental pollution. Accordingly, it can be favorable that other methods
of fertilization be also tested and used to provide necessary nutrients for plant
growth and yield production, while keeping the soil structure in good shape and the
environment clean (Miransari
2011
).
Nanotechnology has provided the feasibility of exploring nanoscale or nano-
structured materials as fertilizer carrier or controlled-release vectors for building of
the so-called smart fertilizers as new facilities to enhance the nutrient use efficiency
and reduce the cost of environmental pollution (Chinnamuthu and Boopati
2009
). A
nano-fertilizer refers to a product in nanometer regime that delivers nutrients to
crops. For example, encapsulation inside nanomaterials coated with a thin protec-
tive polymer film or in the form of particles or emulsions of nanoscale dimensions
(DeRosa et al.
2010
). Surface coatings of nanomaterials on fertilizer particles hold
the material more strongly due to higher surface tension than the conventional
surfaces and thus help in controlled release (Brady and Weil
1999
). Delivery of
agrochemical substance such as fertilizer supplying macro- and micronutrients to
the plants is an important aspect of application of nanotechnology in agriculture. As
mentioned in Table
4.2
, nano-fertilizers show controlled release of agrochemicals,
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