A simple process for generating a greener fertilizer

Nitrogen is a vital nutrient for plants. In large-scale industrialized farming, nitrogen is supplied through fertilizers which are predominantly produced from fossil fuels. Given the need to reduce the use of fossil fuels, researchers look to plasma-activated water (PAW) as a possible alternative fertilizer that is more eco-friendly.

Subramanian et al. developed a dielectric barrier discharge (DBD) plasma reactor that can selectively transfer reactive nitrogen species into PAW. Their tests showed the nitrogen rich PAW to be highly stable at room temperature, with little reduction of nitrogen species in PAW even after four weeks of storage, making it practical for agricultural applications. The device also minimizes the generation of non-desirable reactive oxygen species and consumes 68% less energy than the most efficient of similar technologies.

“Conversion of atmospheric nitrogen to fertilizers is essential to sustain life on the planet, without which the world could not have grown to the current population,” said author Lakshminarayana Rao.

To create the plasma, the authors placed demineralized water in a glass bottle with electrodes attached to its cap. When they applied power to the electrodes, a DBD plasma formed in the air above the water. Then, the power was turned off, and the bottle was shaken to transfer the reactive species into the water, generating the PAW. They also tested this process using tap water because of its accessibility in rural areas where demineralized water may be scarce.

Rao said the process is simple to operate and can be adopted in a practical setup, where the PAW can be implemented as a liquid fertilizer through drip irrigation systems. He noted the wide potential for further optimization.

Source: “Plasma activated water from DBD as a source for nitrogen for agriculture: Specific energy and stability studies,” by P. S. Ganesh Subramanian, Ananthanarasimhan J., Leelesh P., Harsha Rao, Anand M. Shivapuji, Pierre-Luc Girard Lauriault, and Lakshminarayana Rao, Journal of Applied Physics (2021). The article can be accessed at https://doi.org/10.1063/5.0039253 .