Fertilizer International 521 Jul-Aug 2024
31 July 2024
Nanotechnology – hope or hype?
INNOVATION
Nanotechnology – hope or hype?
Indian producers have begun producing nanofertilizers at scale with the backing of the national government, as part of efforts to improve nutrient use efficiency, limit fertilizer subsidies and reduce fertilizer import dependency. But some scientists have questioned the claimed benefits and the overall efficacy of these novel crop nutrient products.
Across the globe, reducing nitrogen inputs to agricultural systems – and therefore their environmental and climate impacts – while maintaining global food production is becoming a major policy goal. The development of more efficient fertilizers, alongside other strategies for improving nutrient use efficiency (NUE), is seen as a stepping stone to agricultural sustainability and securing crop yields and quality (see article on page 16).
Against this backdrop, nanofertilizers have attracted attention in recent times due to their potential to improve NUE, reduce greenhouse gas (GHG) emissions, help prevent nitrogen losses and align nitrogen release with crop demand.
Two Indian fertilizer manufacturers, the Indian Farmers Fertilizer Cooperative (IFFCO) and Coromandel International, have been at the vanguard and pressed ahead with the mass production of liquid nanofertilizers over the last 2-3 years – with the active encouragement of the government in Delhi. This has made the subcontinent a testbed for this innovative technology.
The hope
IFFCO launched the world’s first commercial liquid nanofertilizer – nano urea – in June 2021 (Fertilizer International 503, p20). The proprietary technology was developed at the company’s Nano Biotechnology Research Centre (NBRC) in Kalol, Gujurat.
IFFCO began mass producing half-litre bottles of this pioneering product from three new production plants – Kalol, Gujurat and Aonla and Phulpur in Uttar Pradesh. Initially, these sites were said to provide enough capacity to produce 140 million bottles annually. IFFCO’s entry into this new market has received strong backing from India’s national government with prime minister Narendra Modi attending the Kalol production plant’s official opening ceremony in 2022
Last year, IFFCO and the Indian government announced plans to massively increase liquid nano urea production by building 10 new factories, with an annual production capacity of 440 million bottles by 2025 – and to expand exports of nano urea to 25 countries, mainly in Asia, Africa and South America1 .
Currently, Indian farmers have a financial incentive to overuse urea as it attracts significantly higher government subsidies relative to other types of fertilizer. IFFCO’s new nano urea liquid, in contrast, is potentially a much more efficient nitrogen product. Each bottle contains 40,000 ppm of nitrogen and, according to IFFCO, delivers enough crop nutrients to replace at least one 45 kilo bag of standard commodity urea – at least that is what the initial marketing claimed.
IFFCO’s liquid nano urea (see Table 1 for specifications) has a typical particle size of less than 100 nanometres, contains four percent nitrogen and has a shelf-life of approximately two years. With a zeta potential of greater than 30mV for stability, it is applied as a foliar spray at a dilution rate of 2-4 ml per litre of water, depending on crop nitrogen requirements and canopy development2 .
IFFCO believes its new nano urea product can avoid many of the environmental problems associated with the excessive use of standard granular urea, such as nitrous oxide and ammonia emissions, soil acidification and water eutrophication.
As well as cutting environmental losses, IFFCO says nano urea is more sustainable in other ways: “It will reduce the input cost to farmer. Due to its small size, the bottle can be kept in the pocket and will significantly bring down the cost of logistics and warehousing also,” the company said.
The introduction of nanofertilizers at scale has been heralded as a potential game changer for the Indian market, although this does very much hinge on their widespread acceptance by farmers and the results achieved in the field.
At the start of this year it was reported that IFFCO had produced 77 million bottles of nano urea and sold 54 million bottles to farmers in 2021-22 and 2022-23. IFFCO’s current annual production target – 440 million bottles by 2025 – has the potential to curtail annual usage of standard urea by 20 million tonnes, based on company calculations. This would effectively result in Indian self-sufficiency in urea production and eliminate the need for urea imports into the subcontinent. But only if these sums add up.
India consumes produces and imports urea on a vast scale. Of the 35 million tonnes of urea applied by the country’s farmers each year, imports typically account for some 8-9 million tonnes.
Due to subsidies, while farmers pay less than INR 300 for a 50 kilo bag of urea, each of these bags reportedly costs INR 3,000 to produce. Consequently, India’s fertilizer ministry has estimated that substituting 25 percent of subsidised standard urea with non-subsidised nano urea (INR 225) could save the Indian exchequer up to INR 200 billion ($2.4 billion) every year.
The Indian government therefore has strong financial, trade and agronomic/environmental imperatives that make the mass production of nanofertilizers attractive – as a way of improving urea self-sufficiency, reducing massive expenditure on fertilizer subsidies and preventing nitrogen overapplication and nutrient imbalances.
Nanofertilizer production expands
India is continuing to ramp up nanofertilizer production – with private sector producer Coromandel International opening a new state-of-the art production unit at its Kakinada complex, Andhra Pradesh, on 10th June. This will have the capacity to produce 10 million bottles of nanofertilizers annually. This is additional to Kakinda’s two million t/a production capacity for conventional NPK grades.
Commenting on the new production plant, Mr S. Sankarasubramanian, the Executive Director of Coromandel’s Nutrient Business, said:
“Coromandel’s Nano Fertiliser Plant at Kakinada is a testament to its commitment and dedication to boost nutrient efficiency, reduce environmental impact, and improve the economic viability of farming in India. The government’s push for Nano DAP marks a new era in Indian agriculture, where technology and sustainability go hand in hand. This innovative solution aligns with our goals of enhancing agricultural productivity and farm sustainability and we believe that Nano fertilizers will play a crucial role in shaping the future of Indian agriculture.”
Coromandel has developed nanofertilizer versions of urea and diammonium phosphate (DAP) at its in-house research and development centre at the Indian Institute of Technology (IIT), part of the Bombay-Monash Research Academy. These are marketed under the brand names Gromor Nano Urea and Gromor Nano DAP, respectively.
“The nano-sized fertiliser particles ensure optimal nutrient delivery and absorption by the plants and have the potential to replace the conventional fertilisers while also increasing the crop yield,” Coromandel said in a statement.
Coromandel first unveiled plans to produce a nanotechnology-based phosphate fertilizer in June last year, having received regulatory clearance and completed around 700 crop trials. The
Chennai-based company – part of Murugappa Group – said the efficacy, biosafety and toxicity of Nano DAP has also been extensively investigated via field studies (Fertilizer International 515, p40).
“Nano DAP will go a long way in driving the sustainability of Indian farms through improving nutrient uptake, lowering water consumption and minimising environmental losses,” said Arun Alagappan, Coromandel’s executive vice-chairman, speaking last year.
The adoption of Nano DAP should also make farm economics more attractive by driving sustainable fertilizer usage and site-specific nutrient applications, Alagappan said. He also praised the Indian government for its help (Fertilizer International 515, p40).
“I would like to thank the government for its continuous guidance, extending policy and regulatory support and providing the requisite impetus for adoption of new technologies in farming,” he said.
IFFCO is also scaling-up its production of nanofertilizers. Indian government minister Amit Shah officially launched IFFCO’s new liquid nano DAP product in April last year (Fertilizer International 515, p40).
Half-litre bottles of nano DAP were made available to farmers from the 2023 kharif season at INR 600, less than half the price of a 50 kg bag of conventional DAP.
IFFCO is setting up production plants for nano DAP at Kalol and Kandla in Gujarat and Paradeep in Odisha. The Kalol plant is already in production with IFFCO planning to manufacture 50 million bottles of nano DAP in 2023, said to be equivalent to 2.5 million tonnes of conventional DAP. The company plans to scale up nano DAP production to 180 million bottles by 2025/26.
“The launch of IFFCO’s liquid DAP nano is an important beginning towards making India self-reliant in the field of fertilizers,” Shah said. India currently imports around 10 million tonnes of DAP annually, with more than half of this volume sourced from West Asia and Jordan.
The scientific counterblast
In August last year, two researchers, Max Frank and Soren Husted of the Department of Plant and Environmental Sciences (PLEN) at the University of Copenhagen, published a detailed critique of the scientific claims being made in India for liquid nano urea in an opinion paper for the journal Plant Soil1 .
Both Frank and Husted are active in nanofertilizer research. Husted, for example, presented on the technology at the International Fertiliser Society’s annual conference in Cambridge last year3 .
Setting the scene, the Plant Soil opinion paper noted:
“IFFCO states that there is scientific evidence for distinct beneficial properties in terms of higher crop yields and reduced negative environmental impacts… According to the company, average yield increases of 8% with 50% less N application are possible, thus reducing the costs farmers spend on fertilizers significantly. The product is promoted as being able to reduce nitrate leaching, eutrophication, greenhouse gas emissions, and toxicity to flora and fauna.”
But Frank and Husted questioned whether such claims on the effects and sustainability of nano urea (NU) had been scientifically proven1 :
“We conclude, that NU is a scarcely characterized product with no or poor scientifically proven effects. The product is promoted with misleading and wrong statements about its efficiency as a fertilizer, plant uptake pathways, and environmental friendliness.”
The authors also highlighted potential downsides of mass production of nanofertilizers based on partly substantiated or unsubstantiated claims1 .
“There are several serious risks associated to these commercial ambitions: Large scale yield and economic losses to farmers, food insecurity, environmental risks, social disruption and conflicts,” Frank and Husted concluded, adding: “Politics and commercial incentives might interfere with the independence of the scientists involved.”
The way ahead
The Frank and Husted opinion paper was not entirely negative with the authors stating1 : “We acknowledge the great benefit that nanofertilizers potentially may have – but seriously doubt the positive impact of NU for farmers, societies and the environment as it stands right now.”
Because of this they proposed that independent bodies following a “consistent framework [is necessary] to verify whether novel fertilizer products have indeed beneficial effects for crop growth and yield prior to marketing and applying them widely”.
In particular, the Plant Soil paper suggested adopting the following four criteria when evaluating the superiority – or not – of nano-based nitrogen fertilizers in the field1 :
1. The field study must be conducted on a nitrogen-responsive soil
2. Choose control treatments that fit the conclusions to be drawn
3. Describe materials and methods properly
4. Make an adequate amount of randomised repetitions and apply statistics.
New crop recommendations and product specifications
More evidence is also emerging on the most suitable crop recommendation for nanofertilizers. Results suggest that foliar applied nano urea is most effective when used to replace 25 percent of basal urea applications – and not as the complete replacement that was apparently claimed initially.
A comprehensive review of nano-urea versus conventional urea, for example, was recently published in International Journal of Plant & Soil Science2 . This reported findings of wheat, maize, chickpea and mustard growing experiments carried out by the Indian Agricultural Research Institute.
For these crops, the researchers compared the basal application of prilled urea at the full farmer’s fertilizer practice (FFP) rate for nitrogen – alongside the full recommended rates for phosphorus and potassium – with foliar nanofertilization for nitrogen and zinc. Comparable yields were achieved with nanofertilizers using a basal N application rate at 75 percent of the FFP, with full P and K rates, supplemented by nano urea and nano-Zn foliar sprays achieved.
“Research has demonstrated that utilizing 75% nitrogen with conventional urea, in combination with either one or two sprays of nano-urea, yields results on par with those achieved through the application of 100% nitrogen supplied via conventional urea,” the paper concluded2 .
“When [it was] claimed that one nano-urea bottle of 500 ml is equivalent to one 45 kg bag of granular urea, many farmers believed that and got contrary results after following that prescriptions,” commented the Indian agricultural scientist A K Singh. “What the scientists [now] prescribe – using three bags and one bottle in place of 4 bags – cutting conventional urea usage by 25 per cent is different.”
IFFCO also launched a new nano urea product – Nano Urea Plus – with a much higher nitrogen content in April. This followed a change in specification for nano urea by government after the expiry of the initial spec (see Table 1) issued in 2021. Under the new specification, which is valid for the next three years, liquid nano urea placed on the Indian market will in future need to have a minimum nitrogen content 16 percent by weight.
The new 2024 specification effectively quadruples the nitrogen concentration in each 500 ml bottle of nano urea – versus the nitrogen requirement of just 1-5 percent under the previous 2021 specification. Other values in the 2024 specification, such as particle size, pH, viscosity and zeta potential (Table 1) have been left unchanged.
IFFCO switched over its nano urea production to the new specification (Nano Urea Plus) from May this year. The selling price of nitrogen-enriched Nano Urea Plus is likely to be same as the original Nano Urea product. This has remained at INR 225 per 500 ml bottle since its launch
U S Awasthi, the managing director & CEO of IFFCO, said: “IFFCO Nano Urea Plus is an advanced formulation … redefined to meet crop nitrogen requirement at critical growth phases. It also enhances the availability and efficiency of micronutrients. It is chlorophyll charger, yield booster and will help in climate smart farming.”
Author’s note
The evidence base on the crop benefits of nanofertilizers is contested and still emerging. A definitive review of the efficacy of nanofertilizers, and the rival claims about their merits, is therefore outside the scope of this article. We’d also like to make it clear that the views expressed or quoted in this article do not represent those of CRU Group, Fertilizer International or the author.
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