g-C₃N₄ promotes agro-ecosystem productivity: a case study for rice

Due to the properties of large surface area, light absorption capability and enzyme mimicry, carbon-based nanomaterials show great promise for agricultural sustainability. However, a systematic survey on agro-ecosystems over an entire crop growth cycle is still lacking to date. To this end, in the present study, the effect of carbon nitride (g-C3N4 and Fe-C3N4) on a rice field was investigated over a rice life cycle (4 months) using a column experiment. The as-synthesized g-C3N4 and Fe-C3N4 nanomaterials exhibited a broad-band light absorption ability. In this respect, the photosynthesis-related enzyme activities increased significantly with the addition of g-C3N4 and Fe-C3N4 to the soil. However, only 5% Fe-C3N4 increased the NADPH activity. The chlorophyll content was increased with the addition of 0.2% Fe-C3N4. Consequently, the main agronomic traits (plant height and rice tillers) and yield of rice did not change significantly during the different growth periods, while there was a significant increase in vegetative cover, five hundred grain weight and organic matter of straw during panicle fertilization. For the below-ground fraction, g-C3N4 (0.2%) increased the content of total nitrogen (TN), the content of organic matter (SOM) during the soil spike fertilization period and the associated enzymatic activity, suggesting that this nanomaterial stimulates potential improvements in soil nutrition. These findings indicate that such C3N4-based materials have the potential to be beneficial to agro-ecosystem productivity regardless of plant physiology and soil fertility sustainability.