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Seeds of Doubt Remain About Nanotechnology Use in Agriculture

By Melanie Kah

A new meta-analysis has attempted to give a scientific grounding to claims about the risks and benefits of nano-agrochemicals, but knowledge gaps remain.

Credit: Singkham/iStockphoto

According to the United Nations, the world’s population will reach 9.7 billion in 2050, so agricultural production will need to increase by 60% over 2005 levels to feed the world. This raises questions about how such an increase can be achieved by sustainable means with minimum impacts on the environment and human health. Research and innovation will be the key to help agriculture meet this challenge.

Nanotechnology aims to take advantage of new properties that materials develop at the nanoscale (1 nm is 10,000 times smaller than the thickness of a sheet of paper). A frequent objective of research into the agricultural applications of nanotechnology is to achieve a more efficient use of the resources applied in agriculture. For instance, a significant proportion of the pesticides and fertilisers currently applied in the field do not reach their target. Losses of these chemicals in the environment can contaminate soils and waterways, leading to undesired effects on ecosystems and human health.

Nanotechnology can be used to improve the performance of existing agrochemicals so that adequate levels of plant protection and nutrition can be provided while using less pesticides and fertilisers. Such targeted delivery of pesticides and fertilisers could greatly improve the sustainability of current agriculture. However, the prospect of reducing the negative impact of agrochemical use is matched by concerns about possible new risks associated with the use of nano-enabled agrochemicals.

There is sometimes the perception that nano is more risky than non-nano, but it is not always clear whether this is supported by existing scientific knowledge. Do we know enough to evaluate the performances and unwanted impacts of nano-enabled agrochemicals? How can we measure whether nano-enabled agrochemicals are superior to conventional agrochemicals?

A team of researchers from Australia, Austria and Switzerland has recently made the first systematic comparison of nano-enabled and conventional agrochemicals based on the results of about 80 peer-reviewed publications. The aim of the meta-analysis, published in Nature Nanotechnology (, was to offer factual comparisons for a number of key characteristics including efficacy, environmental fate and particle size, and to provide the basis for informed discussion with the research community, industry, regulators and the public.

The scientific literature confirmed that nanoformulations can greatly alter the properties of pesticides and fertilisers. Our analysis indicates that pesticides and fertilisers with nano-sized ingredients may be 20–30% more efficient than conventional products. However, the gains vary significantly from one product to another.

The fate of agrochemicals after they are sprayed in the fields is determined by many complex processes, and this may affect their environmental impact. This means that nano-enabled products must be thoroughly evaluated under field conditions. Comprehensive field studies evaluating the efficiency and environmental impact of these nano-enabled agrochemicals are not yet available in the open literature.

The study identified a number of knowledge gaps that currently prevent the assessment of the true gains that nano-enabled products may offer. It also emphasised that nano-­agrochemicals encompass a wide variety of products, so different strategies may be needed to assess the new risks and benefits associated with different types of products.

Agriculture is in urgent need of innovation to meet the increasing demand in food while reducing its impact on the environment. The hope is that future research is strategically carried out so that the benefits associated with nanotechnology can be fully harnessed to develop novel nano-agrochemicals that are not only effective and affordable but also help farming to become more sustainable in future.

Melanie Kah is a distinguished visiting scientist at CSIRO Land & Water.