Plasma Activated Water (PAW) in Organic Cultivation: An Experimental Study on Soil Properties and Plant Responses

Plasma-activated water (PAW), known for containing reactive oxygen and nitrogen species (RONS), is used to improve different agronomic traits in crops. However, its effects on soil microbial dynamics and plant growth under organic management remain underexplored. This study aimed to explore the effect of plasma-activated water (PAW) on soil properties and the growth performance of spinach (Spinacia oleracea L.) in an organic soil environment. The ultrahigh electron density nonequilibrium atmospheric-pressure plasma source (60 Hz-9 kV) was used to generate PAW in this experiment. Soils were treated with PAW at various dilution levels and assessed for microbial biomass, nitrogen mineralization, phosphorus circulation activities and bacterial community compositions using 16S rRNA gene sequencing. Plant growth parameters were also measured following cultivation under the same treatments. The results demonstrated PAW application significantly increased microbial biomass and enhanced nutrient cycling activities. 16S rRNA gene sequencing revealed the application of PAW influenced the indigenous bacterial community compositions. Moreover, PAW treatment also led to a notable improvement in plant growth parameters. Among the treatments, moderately diluted PAW yielded the most pronounced effects. These findings highlight the potential use of PAW to enhance soil fertility and plant growth in organic soil environments.