Nano Coated Fertilisers | 12 Nov 2024

Source: PIB 

Why in News?

Recently, Indian scientists have developed nano coated muriate of potash (nano fertilisers) which can enhance the nutrient use efficiency (NUE) of fertilisers. 

• The coating made of nanoclay-reinforced binary carbohydrates can reduce the recommended fertiliser dose and maintain enhanced crop production. 
• It is mechanically stable, biodegradable and hydrophobic which can enhance NUE by their slow release in soil. 
• NUE is the efficiency of a plant in using applied or fixed nitrogen for biomass production. 

What are Key Facts About Nano Fertilisers? 

• About Nanofertilisers: Fertilisers coated with nanomaterials (particles in the nanoscale range of 1-100 nanometer) are called Nanofertilisers. 
  • These nanomaterials enable controlled release of nutrients into the soil, optimising nutrient availability to plants over a longer period. 
• Nanomaterial Components:  
  • Inorganic Materials: Common inorganic nanomaterials used for nanofertilizers include: 
    • Metal Oxides: Zinc oxide (ZnO), titanium dioxide (TiO2), magnesium oxide (MgO), and silver oxide (AgO). 
    • Silica Nanoparticles: These provide high surface area, biocompatibility, and non-toxicity, enhancing crop quality and supporting sustainable agriculture, especially under stress like salinity. 
    • Hydroxyapatite Nanohybrids: They help in delivering calcium and phosphorus to plants. 
  • Organic Materials: Common organic nanomaterials used for nanofertilizers include: 
    • Chitosan: It is a biodegradable, natural material which helps in delivering nutrients efficiently. 
    • Carbon-based Nanomaterials: Organic nanomaterials such as carbon nanotubes (CNTs), fullerenes, and fullerols increase the rate of germination, the chlorophyll content, and the protein content. 
• Types of Nanofertilizers: Nanofertilisers can be classified based on the method of preparation. 
  • Nanoscale Coating Fertilisers: These fertilisers have nutrients coated in nanoparticles for slow and controlled release. 
  • Nanoscale Additive Fertilisers: Nutrients are added to nano-sized adsorbents, keeping them stable and gradually available to plants. 
  • Nanoporous Materials: Fertilisers in nanoporous materials release nutrients slowly, ensuring plants absorb them fully. 
• Applications in Agriculture:  
  • Precision Agriculture: Nanotechnology is used in precision agriculture to optimise water and fertiliser use, reducing waste and energy consumption. 
    • In Precision agriculture, inputs are utilised in precise amounts to get increased average yields, compared to traditional cultivation techniques.  
  • Soil and Plant Health: Nanofertilisers boost seed germination, nitrogen metabolism, photosynthesis, protein and carbohydrate production, and stress tolerance, leading to healthier crops. 
  • Long-Term Soil Fertility: Nanofertilisers release slowly, helping maintain or improve soil fertility for sustainable crop production. 

What are the Advantages of Nanofertilisers? 

• Enhanced Nutrient Efficiency: Nanofertilisers can minimise nutrient loss due to leaching and runoff, and reduce their fast degradation and volatility. This improves soil fertility and ensures that plants receive nutrients more efficiently. 
• Improved Crop Productivity: The slow and controlled release of nutrients can lead to increased crop yield over time, as plants can access nutrients when needed, resulting in better growth and development. 
• High Surface Area and Penetration Ability: Nanofertilizers possess a high surface area-to-volume ratio, allowing for better nutrient uptake by plant roots. This property also facilitates the penetration of nutrients deeper into the soil. 
• Biofortification: Nanofertilisers can be used to enhance the nutritional content of crops by supplying essential micronutrients, such as iron, zinc, and iodine, through nano-based biofortification.  
• Environmental Benefits: Nanofertilisers can reduce environmental hazards caused by traditional fertilisers, such as runoff and soil contamination, promoting eco-friendly farming practices. 
• Cost Efficiency: Nanofertilisers can minimise costs in the long run by reducing the need for frequent applications. E.g., While conventional urea has an efficiency of about 25%, the efficiency of liquid nano urea can be as high as 85-90%. 
  • Recent advances in manufacturing processes have made them affordable for small-scale farmers and plant breeders. 
• Compatibility with Biofertilizers: Nanofertilisers can complement biofertilisers by supporting the activities of beneficial microorganisms in the soil. For example, enhanced nitrogen fixation by Rhizobium and Azotobacter. 
  • Nano-composite fertilisers boost rhizosphere bacteria, encouraging secondary metabolites that enhance plant growth by promoting root surface colonisation. 

What Challenges are Involved in Use of Nanofertilisers? 

• Impact on Environmental: Nanofertilisers may have potential ecotoxicity risks to the soil, water, and non-target organisms. 
  • Ecotoxicity studies how chemicals, physical agents, or biological stressors harm organisms and the environment. 
• Toxicity to Humans: Nanoparticles can penetrate biological systems more easily than larger particles, which raises potential risks to both human health and the environment. 
• Impact on Soil Microorganisms: Metal or metal oxide nanoparticles may disrupt soil ecosystems, potentially harming beneficial microbes essential for nutrient cycling and soil fertility. 
• Lack of Legislation and Regulation: Currently, there is no adequate legislation or risk management system in place to regulate the use of nanofertilizers which raises concerns about the safety and effectiveness of nanofertilizers. 
  • The use of nanomaterials in agriculture raises concerns regarding regulations and safety standards for both human health and environmental protection. 
• Bioaccumulation: The long-term persistence of nanofertilizers in plant systems may lead to build-up of nanoparticles in the food chain. 
• Decline in Yield: A study has found that there was a 21.6% decrease in wheat yield and a 13% decrease in rice yields with the use of nano urea in India. 

Way Forward 

• Supporting Small-Scale Farmers: Processing abundant phosphate rock resources can make phosphates nanofertilisres more affordable and effective for small-scale farmers. 
• Enhance Farmers’ Reach: Enhance reach of the nano fertiliser in both micro and macro nutrients through Krishi Vigyan Kendras (KVKs), farmer education campaigns etc. 
• Standardisation and Regulation: For nanofertilizers to be widely adopted, there must be clear regulations and standards governing their production, application, and safety. 
• Invest in Fundamental Research: Continued research is needed to understand how nanoparticles interact with plants, focusing on nano-toxicity and safety. 
• Optimise Nanomaterials: Biodegradable nanomaterials, such as those derived from plant-based sources or microorganisms, can reduce potential toxicity and environmental hazards.