Carbon-based nanomaterials in agriculture

This article was originally published at azonano.com, written by Shaheer Rehan

Pesticide and fertilizer use has increased dramatically during the previous two decades. Overuse of fertilizers and pesticides not only inflates agricultural product prices but also damages soil and pollutes the environment.

During plant growth, both abiotic and biotic stresses are present. As a result, finding solutions to help plants cope with stress is critical for resourceful and sustainable agriculture, as well as for decreasing the heavy reliance on chemical treatments.

Role of Nanotechnology in Agriculture

Nano-enabled agriculture is progressing, and nanomaterials have shown promise in agriculture, notably in enhancing crop nutrition, decreasing pests and diseases, increasing stress durability, and measuring plant physiological state.

The main role of nanotechnology in agriculture includes nano-fertilizer and nano-pesticides to monitor products and nutrient levels to boost production without disinfecting lands and waterways, as well as provide a shield against a variety of insect pests and microbiological illnesses.

Benefits of Carbon-based Nanomaterials in Agriculture

Carbon-based nanomaterials (CNMs) are used as fertilizer which is important for the growth of the agricultural industry. Traditional fertilizers are water-soluble and quickly seep into the soil, leading to environmental contamination and higher expenses. Previous research suggests that nano fertilizers outperform conventional fertilizers in terms of effectiveness by 18 - 29 percent.

Carbon nanomaterials (CNMs) can be used as excellent fertilizer carriers due to their stable molecular arrangement, uniform dispersion, and low toxicity in application media. For example, graphene oxide nanoparticles are effective trace element transporters.

Pesticides, in contrast to fertilizers, are an important part of agricultural chemicals. Nonetheless, traditional pesticides create biosafety and pollution concerns among the general public due to their ease of leaching, volatilization, and loss.

Nano-insecticides, nano-herbicides, and nano-fungicides are part of nano-pesticides which have the potential to reduce pesticide volatilization and degradation, improve use efficiency, reduce pesticide consumption, and alleviate environmental problems.

Graphene oxide, for example, has a high pesticide adsorption capacity which is almost in the range of 1200 mg/g for chlorpyrifos. Moreover, the moderate toxicity and strong antibacterial activity are insensitive to pH value variations, making it even more reliable.

Advantages of Carbon Nanotubes in Agriculture

Among all carbon-based nanomaterials, the most effective nanomaterials for agricultural applications are carbon nanotubes (CNTs).

Recent studies show that carbon nanotubes (CNTs) chemically modified with the aliphatic alcohol 1-octadecanol (C18H38O) demonstrated exceptional antibacterial capabilities because the long carbon chains contributed to greater microwave absorption by carbon nanotubes (CNTs). Furthermore, due to their high fluorescence stability and long life, CNTs are widely used in plants under abiotic and biotic stress to detect signaling molecules such as H2O2, Ca2+, and NO.

It has been well established that within the physical array of 10 to 100 microns in plants, the near-infrared fluorescence generated by carbon nanotubes (CNTs) may be suppressed by H2O2, which can be utilized to distantly report plant stress status without inflicting mechanical leaf damage.

Aside from that, tomato seeds can be grown quicker and developed into bigger, heavier sprouts when exposed to carbon nanotubes (CNTs), as compared with other seeds.

How Carbon-based Nanomaterials are Used in Agricultural Applications

Carbon nanomaterials (CNMs) are utilized as light converters for supplementing plant photosynthesis. Through chloroplast photosynthesis, plants transform solar energy into chemical energy.

The sunlight used by chloroplasts is primarily confined in the blue and red regions of the visible spectrum. Therefore, they can be used as light conversion materials to maximize solar energy for expanding the light spectrum for plant photosynthesis. That said, to use carbon nanomaterials (CNMs) as light converters in plants, some important factors such as light conversion efficiency, biocompatibility, and cytotoxicity of light converting carbon nanomaterials (CNMs) in plants, and heat produced during carbon nanomaterials-enabled light transformation in plants must be taken into account.

Recently, Zhu et al. revealed that carbon-based nanomaterials with antifungal characteristics could be used to generate new fungicides. Among the different carbon nanomaterials (CNMs) tested against two plant pathogenic fungi, including nanotubes, fullerenes, and graphene oxide, the single-walled carbon nanotubes (SWCNTs) had the strongest antifungal action.

The use of carbon nanomaterials (CNMs) in applying biosensors, light convertors, fertilizers, pesticides, and agrochemical delivery is notable. However, their impact may change depending on plant species, carbon nanomaterial (CNM) type, and its dosages.

In agricultural applications, carbon-based nanomaterials can make the following contributions:

• Increased agricultural yield with the use of plant growth boosters and innovative nanomaterial-based fertilizers.

• Plant protection products based on nanomaterials, such as insecticides and herbicides.

• The use of nano-encapsulated plant protection agents and slow-release fertilizers to reduce the number of agrochemicals used.

• Nanotechnologies for agricultural practice optimization via precision farming.
  

Challenges in the Agricultural Sector Solved by Carbon-based Nanomaterials

Durability, adaptability, health, and decent exposure are all challenges that farming, agriculture, and environmental assets experience.

In agriculture, carbon-based nanomaterials attempt to decrease the number of pesticides distributed, minimize nutrient leaching in fertilization, and increase pest and disease control output. Nanotechnology has the potential to help the agricultural and environmental industries by producing novel products for pest reduction and increased nutrient absorption capability, among other applications.  

References and Further Reading

Zhu, L., Chen, L., Gu, J., Ma, H., & Wu, H. (2022). Carbon-Based Nanomaterials for Sustainable Agriculture: Their Application as Light Converters, Nanosensors, and Delivery Tools. Plants, 11(4), 511. Available at: https://doi.org/10.3390/plants11040511

Husen, A. (2020). Carbon-based nanomaterials and their interactions with agricultural crops. In Nanomaterials for agriculture and forestry applications (pp. 199-218). Elsevier. Available at: https://doi.org/10.1016/B978-0-12-817852-2.00008-1

Aacharya, R., & Chhipa, H. (2020). Nanocarbon fertilizers: Implications of carbon nanomaterials in sustainable agriculture production. In Carbon Nanomaterials for Agri-Food and Environmental Applications (pp. 297-321). Elsevier. Available at: https://doi.org/10.1016/B978-0-12-819786-8.00015-3

Cherati, S. R., Shanmugam, S., Pandey, K., & Khodakovskaya, M. V. (2021). Whole-Transcriptome Responses to Environmental Stresses in Agricultural Crops Treated with Carbon-Based Nanomaterials. ACS applied biomaterials, 4(5), 4292-4301. Available at: https://doi.org/10.1021/acsabm.1c00108