It's easy to forget where our food comes from when tearing into a mechanically prepared and microwave-heated frozen dinner, but global agriculture is a trillion-dollar business that touches more than just our dinner plates. In order to curb big unintended problems, like extreme water or pesticide usage, scientists say it needs a tiny solution: nanotechnology.
Engineered nanomaterials (ENMs) can be used throughout the cultivation process to deliver targeted nutrients or pesticides to plants. Compared to spraying a generic pesticide or nutrient over a crop, using chemically engineered ENMs instead can ensure that none of the material is wasted. While this solution is more sustainable than traditional agriculture in many ways, the authors of a new study write that not all ENMs are created equal.
Environmental engineers behind a new study explore three important areas of agriculture (soil, seeds, and leaves) to determine how ENMs can best be used to help future-proof essential crops.
Demand for agricultural products is higher than ever, but rising to meet that demand has caused more than a few worrying problems of efficiency and toxicity for agriculture. By 2050, the amount of greenhouse gases, cropland, water, and pesticide usage is expected to go up by 50 to 90 percent of current levels. Worse yet, these increases don't necessarily mean that production will go up by the same percentage. Studies have found that only about 10 percent of pesticides sprayed actually reach their targeted crops and that 50 percent of nitrogen-based fertilizer and 85 percent of pesticides are not absorbed by the crops they're applied to.
Authors of a new study published Monday in the journal Nature Nanotechnology write that this question of agriculture's efficiency and sustainability could affect a lot more than just how many ears of corn grocery stores stock this summer.
"The global agriculture system is complex and integrated, and touches nearly all aspects of our daily lives, both directly and indirectly," write the authors. "Agriculture is the cornerstone of a prosperous global society and, therefore, it is critical to maintain and protect it for future generations... [There is potential] for nano-enabled solutions to increase agrochemical use efficiency and enhance crop production."
In their study, the authors compare ENMs and traditional agriculture methods in three critical areas: soil, seeds, and leaves.
When it comes to soil maintenance, the authors write that the three main objectives are to provide nutrients, prevent insect or microbial disease, and increase the overall nutrient spread of the system. This is typically done using nitrogen-enriched fertilizer but the authors write that metal-oxide based ENMs, such as carbon nanotubes, stand poised to offer an alternative. But, while the porous structure of these ENMs allows them to carry heavy nutrient loads, the researchers found that the energy usage of these nano-particles was in actuality no better than their nitrogen counterparts.
But the story was different when it came to seed and leaf care. The team found that targeted applications of seed coatings and leaf pesticide sprays provided more benefit per unit of material than traditional pesticides and coatings in promoting germination or preventing disease.
While these ENMs offer big potential benefits for curbing wasted agricultural chemicals, the authors stress that human health is also a critical variable in how sustainable these materials might be. This includes everything from potentially ingesting these ENMs on food to drinking water they might contaminate.
"[T]he potential human health and long-term environmental risks that arise from the intentional release of substantial amounts of ENMs into crop systems must be considered alongside the benefits realized through technology development," write the authors.
When comparing the effects of these materials the researchers found that adverse effects were more likely to occur during the creation of these ENMs rather than through their use in agriculture. However, they write that further research still needs to be done into the toxicity of ingested ENMs.
The intersection of nanotechnology and agriculture is still largely in its infancy, but the authors write that being proactive about learning the implications of this new approach to agriculture is paramount for an industry that so closely interacts with our daily lives and well-being.
"For the agriculture sector and nano-enabled applications, these proactive analyses are critically important given the intimate relationship between food production, global health and prosperity," write the authors.
Abstract: The globally recognized need to advance more sustainable agriculture and food systems has motivated the emergence of transdisciplinary solutions, which include methodologies that utilize the properties of materials at the nanoscale to address extensive and inefficient resource use. Despite the promising prospects of these nanoscale materials, the potential for large-scale applications directly to the environment and to crops necessitates precautionary measures to avoid unintended consequences. Further, the effects of using engineered nanomaterials (ENMs) in agricultural practices cascade throughout their life cycle and include effects from upstream-embodied resources and emissions from ENM production as well as their potential downstream environmental implications. Building on decades-long research in ENM synthesis, biological and environmental interactions, fate, transport and transformation, there is the opportunity to inform the sustainable design of nano-enabled agrochemicals. Here we perform a screening-level analysis that considers the system-wide benefits and costs for opportunities in which ENMs can advance the sustainability of crop-based agriculture. These include their on-farm use as (1) soil amendments to offset nitrogen fertilizer inputs, (2) seed coatings to increase germination rates and (3) foliar sprays to enhance yields. In each analysis, the nano-enabled alternatives are compared against the current practice on the basis of performance and embodied energy. In addition to identifying the ENM compositions and application approaches with the greatest potential to sustainably advance crop production, we present a holistic, prospective, systems-based approach that promotes emerging alternatives that have net performance and environmental benefits.