Impacts of Bacillus amyloliquefaciens and Trichoderma spp. on Pac Choi (Brassica rapa var. chinensis) grown in different hydroponic systems

Soilless production systems (i.e hydroponics, aeroponics, aquaponics) have become commonplace in urban settings and controlled environments. They are efficient nutrient recyclers, space savers, and water conservers. However, they lack high levels of biological richness in the root microbiome when compared to soil production systems, which may affect plant health and nutrient uptake. To address this issue and incorporate more sustainable practices, beneficial microorganisms (i.e. <i>Trichoderma</i> spp., <i>Bacillus</i> sp.) can be added in the form of biofertilizers. However, many factors affect impacts of microorganisms and their interactions with plants. In this experiment, Black Summer Pac Choi (<i>Brassica rapa</i> var. Chinensis) was grown for two trials in a Deep-Water system (DWS) or a Nutrient Film Technique system (NFT) with commercial biofertilizers containing <i>Trichoderma</i> spp., <i>Bacillus amyloliquefaciens</i>, a combination of both, and a control. Plant physiology, nutrient composition, and nutrient uptake efficiency (NUE) were generally negatively affected by <i>Trichoderma</i> spp. both growing systems, indicating that <i>Trichoderma</i> may not be recommended for hydroponic production. However, <i>Bacillus amyloliquefaciens</i> showed promise as an effective biofertilizer in the NFT systems and had a positive influence on NUE in DWS.