The agricultural sector is dealing with enormous challenges such as rapid climatic changes, a decrease in soil fertility, macro and micronutrient deficiency, overuse of chemical fertilizers and pesticides, and heavy metal presence in the soil. However, the global population increase has subsequently escalated food demand. Nanotechnology has immensely contributed to sustainable agriculture by enhancing crop production and restoring and improving soil quality.

Nanotechnology is applied in various aspects of agriculture, for example:

1. Nano-pesticide delivery
   

2. Slow and controlled release of nanoparticles containing biofertilizers

3. Transport of genetic materials for crop development

4. Application of nano biosensors for rapid detection of phytopathogen and other biotic and abiotic stresses.

   
   

This article focuses on the recent applications of nanotechnology for sustainable farming and how it influences the future of agricultural developments.

The poor awareness of the farmers in general and the excessive use of chemicals has severely affected the agricultural land as the toxic agrochemicals pollute the surface and groundwater. The increased use of chemical pesticides also eliminates beneficial microbes, insects, and other wildlife from the soil. The cumulative effect of all of the above results in major degradation of the ecosystem.

Nanoparticles Commonly Used in the Agricultural Sector

Several nanoparticles are commercially used in agriculture. Some of the commonly used nanoparticles are mentioned below:

Polymeric nanoparticles

In the agricultural sector, polymeric nanoparticles are used in the delivery of agrochemicals in a slow and controlled manner. Some of the advantages of polymeric nanoparticles are their superior biocompatibility and minimal impact on non-targeted organisms.

Some of the polymeric nanomaterials used in agriculture are polyethylene glycol, poly(epsilon-caprolactone), poly(lactide-co-glycolides), and poly (γ-glutamic acid).

Silver nanoparticles

Silver nanoparticles are extensively used for their antimicrobial property against a wide range of phytopathogens. Scientists have also reported that silver nanoparticles enhance plant growth. 

Nano alumino-silicates

Many chemical companies use nano alumino-silicate formulations as an efficient pesticide.

Titanium dioxide nanoparticles

These nanoparticles are biocompatible and are used as a disinfecting agent for water. 

Carbon nanomaterials

Carbon nanoparticles such as graphene, graphene oxide, carbon dots, and fullerenes, are used for improved seed germination.

Some of the other nanoparticles that are used in agriculture are zinc oxide, copper oxide nanoparticles, and magnetic nanoparticles.

Agricultural Nanotechnology for the Enhancement of Crop Productivity 

Nanopesticides and nanoherbicides

The application of nanoherbicides and nanopesticides for the management of weed and pests have significantly increased crop productivity. Different types of nanoparticles such as polymeric nanoparticles and inorganic nanoparticles are utilized for the nanoherbicide formulations.

Scientists have developed various routes for the efficient delivery of herbicides. For example, poly (epsiloncaprolactone) nanoparticles encapsulate atrazine, a herbicide. This nanocapsule showed strong control of the targeted species, reduced genotoxicity level, and could also significantly decrease the atrazine mobility in the soil.

Nanomaterials for disease management

Huge agricultural losses are incurred annually owing to microbial (virus, fungus, and bacteria) infections.

Nanomaterials with specific antimicrobial properties help prevent microbial infestations. Some of the common pathogenic fungi that cause diseases are Colletotrichum gloeosporioides, Fusarium oxysporum, Fusarium solani, and Dematophora necatrix.

Several nanoparticles such as nickel ferrite nanoparticles and copper nanoparticles, have a strong antifungal property and are effectively used in disease management. In the case of viral infection treatment, chitosan nanoparticles, zinc oxide nanoparticles, and silica nanoparticles are effective against viral diseases such as mosaic virus for tobacco, potato, and alfalfa.

Nanofertilizers

Scientists have used nanotechnology to design a smart delivery system that would release nutrients in a slow and controlled manner to the targeted site to tackle nutrient deficiency in plants.

Nanofertilizers increase crop productivity by enhancing the availability of essential nutrients to the plant.

A significant increase in the yields of millet and cluster beans was found after the application of nanophosphorus fertilizers in arid conditions. Chitosan nanoparticles suspensions containing nitrogen, phosphorus, and sodium have also increased crop production. 

Nanotechnology in seed development 

Seed quality is an important factor which crop productivity depends on.

It has been observed that carbon nanotubes can enter the hard seed coat of tomatoes and significantly improve the germination index and plant growth.

Similarly, the germination percentage increased when soybean and corn seeds were sprayed with a multiwall carbon nanotube. Various nano treatments are available to enhance the germination index of plants.

Nanobiosensors 

Nanobiosensors are highly sensitive and specific when compared to conventional biosensors. These devices convert biological responses to electrical responses via a microprocessor.

Nanobiosensors offer a real-time signal monitoring and are involved in direct or indirect detection of pathogenic microorganisms, antibiotic resistance, pesticides, toxin, and heavy metal contaminants. This technology is also used to monitor crop stress, soil health, plant growth, nutrient content, and food quality.

Futuristic Strategies and Policy Options for Sustainable Farming Using Agricultural Nanotechnology

The following are some of the strategies devised for sustainable farming using agricultural nanotechnology:

1. Controlled green synthesis of nanoparticles
   

2. Understanding of nanoparticles produced by root endophytes and mycorrhizal fungi, which play an important role in plant productivity and disease management 

3. Interaction of nanoparticles with plant system such as transport mechanism of nanoparticles inside plant body

4. Critical evaluation of the negative side effects of nanoparticles on different environmental conditions

5. Development of portable and user-friendly nanobiosensors for rapid analysis of soil, plants, water, and pesticides                                      

Some of the policy options for the application of nanotechnology for sustainable development of agriculture are listed below:

1. Development of special institutions with expertise for the proper evaluation for biosafety of nanoparticles
   

2. Formation of clear guidelines following Food Safety and Standards Authority (WHO standards) for monitoring and evaluation of nanoparticle-based systems

3. Proper documentation of nanomaterials-based toxicity to the aquatic organisms

4. More collaborative research and sharing of resources for the development of a better research system

5. For effective use of nano-based products, farmers should be educated by skilled professionals to minimize field problems.                            

   From AZoNetwork