Effect of Carbon Nanoparticles in Biochar and Sulphur as a Foliar Spray on Onion Plants: A New Orientation

Abstract

Biochar contains raw carbon nanoparticles. Water-soluble dried carbon powder nanoparticles (wsCNPs) isolated from leftover biomass (waste stems and roots) in agricultural land can enhance the overall growth rate of onion (Allium cepa L.) plants. Field experiments conducted in 2017–2018 and 2018–2019 aimed to evaluate the effect of wsCNPs and sulfur as a foliar spray on vegetative growth, yield, and some nutritional values of onion plants. The biochar used in the study solution, namely, wsCNPs, was applied at 300, 400, and 500 mg/L incorporated with three levels of 2.5, 3.5, and 4.5 g/L of sulfur (Thiovit, 80%) as a foliar spray. Results indicated that treated plants with all levels of wsCNPs and sulfur had significantly higher values of vegetative growth parameters, photosynthetic pigments, yield, bulb quality, and phytochemical compounds compared with untreated plants. Using the highest foliar spray level of wsCNPs and sulfur obtained significant results for all evaluated characteristics among other levels. This increment was more pronounced when wsCNPs and sulfur were combined, indicating that spraying is a useful agriculture and eco-friendly practice for sustainable crop production.