Prospects of 2D graphene nanomaterials in plant-based agriculture and their fate in terrestrial soil: a critical review

To achieve a world without hunger, it is imperative to address the inefficiencies within the current agricultural system by adopting innovative and sustainable approaches. One such approach involves the use of graphene-based nanomaterials (GNMs), which have shown potential in alleviating plant stress, improving the performance of agrochemicals, enhancing fertilizer retention in the soil, and positively affecting plant productivity. This review explores the potential of GNMs as amendments in conventional agricultural practices and discusses the interactions with both biotic and abiotic components present in agriculture. Analysis of the literature showed that the biocidal action of GNMs in a complex soil matrix tends to be lower when compared to a short-term (1-3 h) toxicity test in pure culture media. Incorporation of 1 ng kg⁻¹ to 5 g kg⁻¹ GNMs in soil for an exposure time of 3 to 365 days showed a transient effect on the soil microbial community, their activity, and soil function. When plant productivity is considered, addition of 50 mg kg⁻¹ to 150 g kg⁻¹ GNMs into soil showed positive impacts on plant productivity for an exposure time of 3 h to 120 days. However, it is important to note that outcomes of GNM interaction in agriculture will depend significantly on factors such as the type of GNM, application dose, exposure time, and experimental conditions. Additionally, in subsurface soil, GNMs are likely to bio-transform, which will alter their biotic/abiotic interactions. The understanding of how GNMs impact agriculture is still in its infancy, and there are discrepancies in study findings primarily due to the diversity and complexity across agricultural systems. There is a need for mechanistically enriched research on GNM interaction and fate in agricultural systems that will pave the way to efficient design of GNM application in improving yield and to obtain a food secured future.