Smart Nanofertilizers
Mineral nutrients such as
nitrogen, phosphorous potassium, calcium, magnesium, sulphur, and other
micronutrients are essential for plant growth and crop production. Presently, we face a glaring contrast of
insufficient use of nutrients on one hand and excessive use on another.
Nutrients Use efficiency (NUE) represents a key indicator to assess progress
towards better nutrient management. Fertilizers are chemical compounds applied
to promote plant growth. It is applied either through the soil or by foliar
feeding. Artificial fertilizers are inorganic fertilizers formulated in
approximate concentration to supply the nutrients. Nitrogen is an important
source which is essential for the growth of plant. Urea is the most wildly used
water soluble plant nitrogen source. Due to leaching the nitrogen content in
the soil get decreased leading to low nitrogen utilization efficiency.
Nitrogen-use efficiency for most
crops ranges from 30 to 50 percent, so researchers are developing intelligent
nano-fertilizers to reduce the amount of nitrogen lost during the crop
production. The plant needs different
amount of nitrogen depending on its growth stage. A new generation of
fertilizers will increase this efficiency from 30 percent to upwards of 80
percent. The idea is to develop a product that will release nitrogen only when
the plant needs it and in the amount the plant needs. The plants communicate
their surroundings environment by producing all kinds of chemical signals. A
plant synthesizes specific compounds to communicate with specific microbes. The
microbes then go to work and free nitrogen that the plant uses to grow. Thus,
roots send out signal that ask microbes to transform nitrogen in the soil into
a chemical form the plant can use. Many chemical compounds that are
associated with nitrogen uptake have
been identified. These compounds can be used to synchronize the release of
fertilizer with nitrogen uptake by the crop.
A biosensor is a device that
combines a biological recognition element with a physical or chemical
transducer to detect a biological product. In other words, it is a probe that
integrates a biological one with an electronic component to yield a measurable
signal. Several biosensors are being developed for different applications.
Typically a biosensor consists of three components: the biological recognition
element, the transducer and the signal processing electronics. Nano-biosensors
that will bind to these compounds can be developed so as to control of the
release of fertilizers. The polymers coatings that protects the fertilizers
from the elements contains nano-sized biosensors which are made up of very
specific chemical compounds that allow the fertilizers to be released into the
soil when the plant needs it. These biosensors know when to release nitrogen
because they are able to detect chemical signals released from the roots of the
plant to the soil. Biosensors can detect when a plant requires more nitrogen
and allow microbes access to the fertilizer-nitrogen inside the polymer protected
particles.
Each
plant species sends out its own variety of chemical signals. Keeping this
concept in mind, a smart nano-fertilizer product could be tailored to
respond differently to the needs of different crops. For instance, the nitrogen
particles could be designated to become available to wheat, but not to the
canola growing in the same field because of different compounds emitted by
different crops. We can prepare different biosensors using different compounds
and tailor the fertilizers to each different crop for different climatic zones
and soils. Dr. Carlos Montreal of Agriculture and Agri-Food Canada in Ottawa is
one of the several research scientists developing a fertilizer that responds to
organic compounds emitted by a plant’s roots. The research team is trying to
make intelligent fertilizers with the
biodegradable three-dimensional polymer coating less than 100 nm thick. Hence,
in coming years farmers could have access to an intelligent
nano-fertilizers that synchronizes the
release of nitrogen with crop uptake.
