Unveiling the Effects of Carbon-Based Nanomaterials on Crop Growth: From Benefits to Detriments

Abstract

To systematically assess the impact of typical CNMs on the growth effects of cereal crops, we conducted a metaanalysis of 48 independent studies worldwide. The pooled results showed that shoot weight (13.39%) and antioxidant metabolite content (SOD: 106.32%, POD: 32.29%, CAT: 22.63%) of cereal crops exposed to the presence of CNMs were significantly increased, but phytohormones secretion (17.84%) was inhibited. The results of subgroup analysis showed that there were differences in the results of different CNM types with the same exposure concentration on growth effects. Short-term exposure adversely affected the root and photosynthetic capacity of the crop, but prolonged exposure instead showed a promoting effect. Multiple linear regression analysis showed that the concentration of CNMs and cereal variety variables were significantly associated with changes in multiple growth effect values. This work could offer references and fresh perspectives for investigating how nanoparticles and crops interact.

Sustainable Technological Applications of Green Carbon Materials

“…Traditional agricultural NPK inorganic fertilization markedly contributes to the carbon footprints of products, contributing negatively to the sustainability of agricultural farms. Carbon nanomaterials are being proposed as potentially more sustainable agents to be used in agricultural practices [20,23]. Although there is no common effect on all plants exerted by carbon nanomaterials, an increasing trend in production yields is observed (Figure 3) [20].…”

“…Carbon nanomaterials are being proposed as potentially more sustainable agents to be used in agricultural practices [20,23]. Although there is no common effect on all plants exerted by carbon nanomaterials, an increasing trend in production yields is observed (Figure 3) [20]. However, most of the research work in this area has been done with well-characterized carbon nanomaterials like graphene oxide (GO), carbon nanotubes (CNT), and fullerenes, among others [20,23], which are not synthesized from renewable biomass, and sustainability is compromised.…”

“…Although there is no common effect on all plants exerted by carbon nanomaterials, an increasing trend in production yields is observed (Figure 3) [20]. However, most of the research work in this area has been done with well-characterized carbon nanomaterials like graphene oxide (GO), carbon nanotubes (CNT), and fullerenes, among others [20,23], which are not synthesized from renewable biomass, and sustainability is compromised. Nitrogen-doped carbon dots (N-CD) were synthesized from fresh betle leaves (Piper betle) [24].…”

“…Biochar is added to soil to modify its physical and chemical composition, microbial activity, soil fertility, and pollution load [28][29][30][31][32][33][34][35][36][37]. Carbon nanomaterials have another important role in agricultural practices, namely as nanocarriers for pesticides and fertilizers, allowing the controlled release of active molecules [20]. Nevertheless, carbon nanomaterials must have intrinsic sustainability, i.e., being synthesized from renewable raw materials (GCN), and, in the agriculture business, the incorporation of agricultural residuals into the productive cycle is highly encouraged within the ongoing transition to the circular economy.…”

“…GCM can be produced as a by-product of GCN synthesis or by the direct carbonization or pyrolysis of the biomass. For example, biomass as a raw material for GCN production originated from an insoluble activated carbon material, besides the soluble nanomaterial, with a large specific surface area of about 295 m 2 /g [20]. Biochar is a typical GCM obtained directly from renewable biomass or waste and is produced by heating at high temperatures without oxygen (for example, in the presence of nitrogen and/or carbon dioxide), followed by a final physical-chemical transformation for functionality tuning (Figure 2) [15].…”