DEEPIKA SAHU*, ANJALI PATEL#
*Department of Soil Science and Agricultural Chemistry, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh 492001
#Department of Agronomy, Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh 492001

    "There’s Plenty of Room at the Bottom" Richard Feynman Cal Tech, 1959
Why cannot we write the entire 24 volumes of the Encyclopedia Brittanica on the head of a pin?
This goal requires patterning at the 10 nanometer scale.

What is Nanotechnology?
Nanotechnology is the understanding and control of matter of sizes roughly in the range of 1 to 100 nanometers. If one of the dimensions is in this range, it is considered a nanoparticle.
  • Nanotechnology deals with the matter at nanoscale (1-100 nm) dimensions. These materials when reduced to the nanoscale show some properties which are different from what they exhibit on a macro scale, enabling unique applications.
  • Nanotechnology has great potential, as it can enhance the quality of life through its applications in various fields like agriculture and the food system. This technology can boost agricultural production.
  • Bulk materials when reduced to the nanoscale show some properties (melting point, physical strength, surface area, penetration power, electric conductance, optical effect, magnetism etc.) which are different from what they exhibit on a macro scale enabling unique applications.
  • These materials can be either natural or engineered.
  • At nanoscale, gravity would become less important, whereas surface tension and van der Waal forces would become more important.
Figure: Scope of nanotechnology
 
Unique characteristics of Nanoparticles
  • Large surface to volume ratio.
  • High percentage of atoms/molecules on the surface.
  • Surface forces are very important, while bulk forces are not as important.
  • Metal nanoparticles have unique light scattering properties and exhibit plasmon resonance.
  • Semiconductor nanoparticles may exhibit confined energy states in their electronic band structure (e.g. quantum dots).
  • Can have unique chemical and physical properties.
  • Same size scale as many biological structures.

The properties that change at nano level
  • Optical properties
  • Thermal properties
  • Conductivity
  • Resistivity
  • Physical properties (stress, strain)
  • Chemical properties (catalytic behavior)
  • Magnetic properties

Properties of nano-particle
  • Large proportion of surface atoms - Smaller particles allow better coverage of surface area.
  • Nano sized particles can even pass through the cell wall in plants and animals.
  • Nanotechnologists use this process to deliver at cellular level which is more effective than the conventional method.
  • High surface energy.

Concept and Basics of Nanoscience and Nanotechnology
Nanoscience is the investigation of matter at a scale which is intermediate between bulk matter', described by Newtonian Physics and 'atomic matter' (atoms, electrons etc.) described by Quantum Physics. The exceptional properties of matter at the nanoscale have prompted scientists to re-invent the way materials are engineered and produced.
  • When particles assume nanoscale dimension, the principles of classical Physics are no longer capable of describing their behavior (movement, energy, etc).
  • At these dimensions, quantum mechanics principles apply.
  • The same material (e.g., gold) at the nanoscale can have properties (e.g., optical, mechanical, electrical, etc.) which are very different from the properties the material has at the macro scale (bulk).

What’s Different About a Nanoparticle?
  • There are various reasons why nanoscience and nanotechnologies are so promising.
  • First, at the nanometer scale, the properties of matter, such as energy, change.
  • This is a direct consequence of the small size of nanomaterials, physically explained as quantum effects. The consequence is that a material (e.g., a metal) when in a nano-sized form can assume properties which are very different from those when the same material is in a bulk form.
  • For instance, gold, although inert in the bulk form, when broken into particles in the 10 100 nm range, becomes a highly effective catalyst. Carbon atoms can be arranged into nanotube structures that are stronger than steel.
  • Properties like electrical conductivity, color, strength and weight change when the nanoscale level is reached.
Figure: Quantum effect on gold ring and gold nanoparticle showing change in colour at course fine and ultrafine particle size


Synthesis of Nanoparticles
Atoms and molecules are the basic building block of construction of every object. It is the way in which it is constructed which determines its properties. Nanoparticles can be constructed by a variety of methods. Two approaches are generally involved in the generation of nanoparticles which are as shown below.

Figure: Approaches of nanoparticle synthesis


Nanomaterials can occur naturally as well it can be produced by human activity either as a product of another activity on purpose (engineered).

Applications of Nanotechnology
  1. Nano formulations of agrochemicals for applying pesticides and fertilizers for crop improvement.
  2. The application of Nano sensors/Nano biosensors in crop protection for the identification of diseases and residues of agrochemicals.
  3. Nano devices for the genetic manipulation of plants; plant disease diagnostics.


Nanosensors in Agriculture
  • Nanosensors development can help in determining the required amount of farm inputs such as fertilizers and pesticides.
  • Nanosensors for pesticide residue detection offer high sensitivity, low detection limits, super selectivity, fast responses, and small sizes.
  • They can also detect level of soil moisture and soil nutrients.

Nano fertilizers
  • Nanoparticles have high surface area, sorption capacity, and controlled-release kinetics to targeted sites making them “smart delivery system”
  • Nanostructured fertilizers can increase the nutrient use efficiency through mechanisms such as targeted delivery, slow or controlled release
  • In recent lab scale investigations, it has been reported that nano-fertilizers can improve crop productivity by enhancing the rate of seed germination, seedling growth, photosynthetic activity, nitrogen metabolism, and carbohydrate and protein synthesis.

Carbon nano tubes
  • This demonstration shows that the exposure of carbon nanotubes to seeds of valuable crops, such as tomatoes, can increase the germination percentage and support and enhance the growth of seedlings.


Zinc nano fertilizers
  • Zinc oxide nanoparticles (ZnO NPs) also have remarkable optical, physical, and antimicrobial properties and therefore have great potential to enhance agriculture
  • Zinc oxide NPs have potential to boost the yield and growth of food crops.
Eg. Peanut seeds were treated with different concentrations of zinc oxide nanoparticles. Zinc oxide nanoscale treatment (25 nm mean particle size) at 1000 ppm concentration was used which promoted seed germination, seedling vigor, and plant growth and these zinc oxide nanoparticles also proved to be effective in increasing stem and root growth in peanuts.

IFFCO NANOFERTILIZERS
  • IFFCO introduced India’s first Nanotechnology based products for On-Field trials on 2019.
  • ‘Nano-technology’ based product range by introducing Nano Nitrogen, Nano Zinc, Nano Copper for on-field trials at an event held at its mother unit in Kalol, Gujarat.
  • These Nano products were launched for field trials by Sh. Sadananda Gowda, Union Minister of Chemicals & Fertilizers; Sh. Mansukh Mandaviya, Union Minister of State for Shipping (Independent Charge) and Chemicals & Fertilizers and other dignitaries.

LAUNCHED NANOFERTILIZER PRODUCTS OF IFFCO
  • The first is IFFCO NANO NITROGEN which is developed as an alternative to Urea. If used properly, this product has the potential to cut the requirement of Urea by 50%.
  • The second is IFFCO NANO ZINC which is developed as an alternative to the currently used Zinc fertilizers.
  • Only 10 gm of this product would be sufficient for a hectare of land and would bring the requirement of NPK fertilizer down by 50%.
  • The third product is IFFCO NANO COPPER which provides both nutrition and protection to the plant.
  • It boosts the plants immunity against harmful pathogens and helps increase the activity of plant growth hormone and improves overall plant growth and development.”

BENEFITS OF NANOFERTILIZERS
These nano structured formulations effectively deliver nutrients to the plant. Other benefits of these Nano-products include: –
  • Reduction in the requirement of conventional chemical fertilizer by 50%.
  • Upto 15-30% increase in crop production
  • Improvement in soil health
  • Reduction in the emission of greenhouse gasess
  • Environment friendly

Conclusion
Nanotechnology will play a vital role in the development of the agricultural sector, as it is capable of being used in agricultural products that protect plants and monitor plant growth and detect diseases. Scientists have been working towards exploring new applications of nanotechnology in agriculture and the food industry - if these discoveries are applied sensibly, the environment, the agricultural sector and the food industry will indeed see tremendous changes for the better in the coming years.