Phosphate-rich and potassium-rich water produced by atmospheric pressure plasma jet for plasma agriculture

The applications of plasma-activated water have drawn a lot of attention in plasma agriculture in recent years. Plasma-activated water provides the reactive oxide and nitrogen species in water, and the rest of the nutrients are supplied by the chemical fertilizer or organic fertilizer in previous studies. We report the procedures to produce the phosphate-rich water and potassium-rich water by atmospheric pressure plasma jet to fill in the blanks of major nutrients in plasma agriculture. The production rate of phosphoric acid is found greatly enhanced by using an air plasma jet compared with an N2 and CO2 plasma jet. We show the concentration of potassium-rich water is affected by the oxide layer on the potassium chunk. Potassium-rich water is more effectively produced in air and CO2 plasma jets than in N2 and Ar plasma jets, which is evidenced by the plasma emission spectrum intensity and current profile. Taking the growth of Arabidopsis thaliana as an example, we demonstrate that the plasma fertilized waters, including the nitrate-rich water, phosphate-rich water, and potassium-rich water, can help the growth of plants in plasma agriculture.