Non-Thermal Plasma treatment influences shoot biomass, flower production, and nutrition of gerbera plants depending on substrate composition and fertigation level

Non-thermal plasma (NTP) appears a promising strategy for supporting crop protection, in-creasing yield and quality, and promoting environmental safety through a decrease in chemical use. However, very few NTP applications on containerized crops are reported under operational growing conditions and in combination with eco-friendly growing media and fertigation man-agement. In this work, the NTP technology was applied on the nutrient solution used for the production of gerbera plants grown on peat or green compost, as an alternative substrate to peat, and with standard or low fertilization. NTP treatment promoted fresh leaf and flower bi-omass production in plants grown on peat and nutrient adsorption in those grown on both sub-strates, except for Fe, while decreased plant dry matter. However, it caused a decrease in leaf and flower biomasses of plants grown on compost, showing a substrate-dependent effect highlighted under a low fertilization regime. In general, the penalty on compost was probably caused by the high substrate alkalinisation that commonly interferes with gerbera growth. Under low fertili-zation, a reduction in the photosynthetic capacity further penalized plant growth on compost. The lower level of fertilization also decreased gerbera quality anyway highlighting that Ca, Mg, Mn, and Fe could be reduced respect the standard fertilization.