Sustainable crop development is a hot topic in agriculture right now. Scientists are striving to establish practices that support sustainable crop development to meet the evolving demands of the food supply chain.
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Nanofertilizers and Sustainable Agricultural Practices
Although chemical fertilizers increase crop productivity, they create an imbalance in the soil's mineral content, decrease soil fertility, and cause irreparable damage to the soil structure and soil microbial flora, affecting food chains across ecosystems.
Chemical fertilizer use is also a major source of water pollution in farming practices due to the run-off of phosphate-rich fertilizer into water sources, causing eutrophication. These fertilizers are also toxic to humans and animals, including marine life, and, therefore, they are not suitable for sustainable crop development.
The rapid growth in the world population has increased the demand from the agricultural sector. It is estimated that food production would need to double the amount produced in 2009 to meet the needs of the expected nearly 10 billion inhabitants on Earth.
For this reason, researchers are wary of the overuse of chemical fertilizers by farmers and are pushing for long-term sustainable farming solutions with low environmental impact. The increased use of chemical fertilizers from ramping up agricultural activities would increase the negative impact of these fertilizers on the planet; thus, they do not support sustainable crop development.
Nanofertilizers have emerged as a promising alternative that ensures high crop production and soil restoration. As a result, it has become a promising tool for sustainable crop development. The total global market for nanofertilizers was valued at an estimated $3 billion in 2022 and is predicted to grow at a CAGR of 14.27% from 2023 to 2031. The urge to shift from chemical fertilizers to nano-fertilizers is predicted to be a major driver of the market over the next decade.
Nanofertilizers Vs. Conventional Fertilizers
The unique properties of nanoparticles, such as high sorption capacity, the increased surface-to-volume-ratio, and controlled-release kinetics to targeted sites, make them a potential plant growth enhancer.
Because of these characteristic features, nanofertilizers can be used as a smart delivery system of nutrients to the plant. Nanofertilizers are released very slowly in comparison to conventional fertilizers. This approach improves nutritional management, i.e., increasing nutrient-use efficiency and decreasing nutrient leaching into groundwater.
Nanofertilizers, due to their nanoscale size, can easily be absorbed into the roots of plants. This means that vital nutrients such as iron, calcium, copper, and silver can be effectively absorbed, helping to grow stronger, healthier crops.
Nanofertilizers are specifically designed to release active ingredients in response to biological demands and environmental stress. Scientists have further stated that nanofertilizers increase agricultural productivity by improving photosynthetic activity, seedling growth, rate of seed germination, nitrogen metabolism, and carbohydrate and protein synthesis.
Other benefits of nanofertilizers over traditional chemical fertilizers included reduced soil toxicity, increased plant photosynthesis, reduced environmental pollution and decreased frequency of application. All these factors make them a favorable option for sustainable crop development.
Development of Effective Nanoformulations for Sustainable Crop Development
There are several ways in which nano-fertilizers are being produced for sustainable crop development. Nanoformulations or nanoscale fertilizers are made from ammonium humate, ammonia, urea, peat, plant wastes, and other synthetic fertilizers. An example of nanoformulation is nano-sized nitrogen (N) fertilizer which is prepared as a result of the deposition of urea on calcium cyanamide.
Nanonitrogen fertilizers are instrumental in enhancing the productivity of rice. This is regarded as an excellent alternative to chemical fertilizers because it promotes growth and reduces environmental pollution. Excessive use of conventional fertilizers causes environmental pollution by leaching, denitrification, and volatilization of chemical fertilizers.
Sustainable crop development of rice crops is, therefore, supported by the use of nanofertilizers due to their reduction in environmental contamination compared with traditional fertilizers.
Another effective nanofertilizer for use in sustainable crop development has been formulated by grinding urea and mixing it with different biofertilizers. This nanofertilizer offers a slow and gradual release of nutrients for a more extended period.
Nanofertilizers are developed using mechanical and biochemical processes, i.e., materials are grounded to obtain nano-sized particles through mechanical means and biochemical techniques are employed to obtain effective nanoscale formulations.
Fertilizers are often encapsulated within nanoparticles. Such nanofertilizers offer a greater absorption capacity and nutrient use efficiency to the plant. The process of encapsulation of nutrients with nanomaterials can be performed in three ways:
• Nutrient particles coated with a thin layer of nanomaterials (polymer film)
• Nutrients encapsulated within the nanomaterials of varying nature and chemical composition
• Nutrients delivered in the form of nanoemulsion
How Do Nanofertilizers Enter the Plant System?
The plant root system, which is the gateway for the nutrients, is more porous to nanofertilizers than conventional fertilizers.
Scientists have conducted experiments using the faba bean (Vicia faba), to determine the nanoparticle's efficiency in penetrating the plant system. They found that smaller nanoparticles were more efficient at achieving leaf penetration than larger particles.
Nanofertilizers also deliver nutrients through plasmodesmata– nano-sized channels of approximately 50–60 nm in size used to transport ions between cells. Carbon nanotubes and silica nanoparticles are useful tools for transporting and delivering cargo (nutrients and other important biochemicals) to plants' target sites.
Use of Nanofertilizers in Sustainable Crop Development
Scientists believe that zinc nanofertilizers are responsible for robust plant growth (shoot and root system) and increase the leaves' chlorophyll content.
In a previous study, the amendment of zinc nanofertilizers significantly increased the yield of peanuts. These nanofertilizers also improve the seed production of vegetables. Similarly, carbon nanotubes containing fertilizers were reported to decrease the days to germination. These nano-fertilizers were also found to promote the development of plant root systems in rice seedlings.
Nanofertilizers also reduce the crop cycle period and increase crop yield. For example, the amendment of nanoparticles carrying NPK (nitrogen, phosphorus, and potassium) to wheat showed an increase in grain yield and reduced the crop cycle of wheat by 40 days. Similar results were obtained in the maize cropping system.
Nanofertilizers will also likely be useful in the growing field of hydroponics, where plants are grown indoors without soil as a method of sustainable crop development. Growing plants hydroponically has become increasingly popular due to the rapidly rising demand for food and increased competition for land to grow it on. With hydroponics, plants can be grown indoors anywhere in the world, removing limiting factors such as season, weather conditions, and available fertile land.
Studies have shown that hydroponically grown plants show traces of nano-fertilizers in their roots, stems, and leaves, demonstrating the efficacy of nanofertilizers in a soil-free environment. Other studies have shown that the use of nano-fertilizers in growing plants hydroponically had the effect of stimulating root growth.
Limitations of Nanofertilizers in Sustainable Crop Development
Despite aiding in sustainable crop development, the limitations of nanofertilizers should be carefully considered before marketing. The limitations of using nano-fertilizers mainly arise due to the absence of rigorous monitoring and research gaps.
Some of the drawbacks associated with the use of nanofertilizers for sustainable crop development are enlisted below.
• Lack of a nanofertilizer risk management system
• Lack of production and availability of nano fertilizers in required quantities. This limits the wider-scale adoption of nanofertilizers as a source of plant nutrients.
• The high cost of nanofertilizers
• Lack of standardization in the formulation process. This brings about different results of the same nanomaterial under various pedoclimatic conditions.
While there are several drawbacks of nanofertilizers in their application in sustainable crop development, as their use increases over the coming decade, some of these challenges will likely be overcome, such as issues with product availability and lack of standardization. Also, as production processes become larger, it is possible that production costs will reduce, causing the cost of nanofertilizers to fall, thus allowing for the widespread use of nano-fertilizers in sustainable crop development.
Nanofertilizer Manufacturing Companies
Some nanofertilizers used in sustainable crop development are:
• AG CHEMI GROUP Ltd (Czech Republic)
• EuroChem (AIM Capital S.E., Switzerland)
• Geolife (Geolife Agritech India Pvt. Ltd., India)
• Indian Farmers Fertilizers Cooperative Limited (India)
• JU Agri Sciences Pvt. Ltd. (Jhaver Group, India)
• Nano Calcium (AC International Network Co., Ltd., Germany)
• Nano-Micro Nutrient (Shan Maw Myae Trading Co., Ltd., India)
• Nano Green (Nano Green Sciences, Inc., India)
• Biozar Nano-Fertilizer (Fanavar Nano-PazhooheshMarkazi Company, Iran)
References and Further Reading
Al-Juthery, H.W.A. et al. (2019) Effect of foliar nutrition of nano-fertilizers and amino acids on growth and yield of wheat. Conference Series: Earth and Environmental Science. 388, 012046. https://doi.org/10.1088%2F1755-1315%2F388%2F1%2F012046
Food Production Must Double by 2050 to Meet Demand from World’s Grow(Accessed May 2023)
Muhammad, A.I. (2019) Nano-Fertilizers for Sustainable Crop Production under Changing Climate: A Global Perspective. https://www.intechopen.com/books/sustainable-crop-production/nano-fertilizers-for-sustainable-crop-production-under-changing-climate-a-global-perspective
Nongbet, A. et al. (2022) ‘Nanofertilizers: A smart and sustainable attribute to modern agriculture’, Plants, 11(19), p. 2587. doi:10.3390/plants11192587.
León-Silva, S. et al. (2018) Design and Production of Nanofertilizers. In: López-Valdez F., Fernández-Luqueño F. (eds) Agricultural Nanobiotechnology. Springer, Cham. https://doi.org/10.1007/978-3-319-96719-6_2
Solanki, P. et al. (2015) Nano-fertilizers and Their Smart Delivery System. In: Rai M., Ribeiro C., Mattoso L., Duran N. (eds) Nanotechnologies in Food and Agriculture. Springer, Cham. https://doi.org/10.1007/978-3-319-14024-7_4
Zulfiqar, F. et al. (2019) Nanofertilizer use for sustainable agriculture: Advantages and limitations. Plant Science. 289:110270. https://doi.org/10.1016/j.plantsci.2019.110270
This article was updated June, 2023.