Plasma-activated water as a green acidifying agent for ammonia nitrogen fixation and sustainable plant cultivation

Excessive nitrogen fertilizer utilization and improper manure management cause severe NH3 losses. Given high cost and complexity of existing ammonia inhibition technologies, this study utilized the dual properties of plasma activated water (PAW) mixed with ammonia source, which has been demonstrated to effectively inhibit NH3 volatilization and enhance nitrogen content. To evaluate its feasibility as a novel nutrient solution and its effects on plant growth, hydroponic experiments were conducted using PAW-ammonia mixtures (PAW+NH) and PAW at various dilutions, with deionized water as a control. Results showed that 10-fold diluted PAW+NH best promoted wheat, buckwheat, and mung bean heights (34%, 46%, 23% higher), while single PAW inhibited growth. PAW+NH and its dilutions outperformed PAW and its dilutions at the same ratio. Physiologically, protein content and SOD activity increased with growth, while MDA content was negatively correlated. The optimal effect of 10-fold diluted PAW+NH was due to suitable pH and adequate, properly concentrated nitrogen, avoiding adverse nitrogen excess damage.