Evaluation of phosphorus and COD concentrations in bioponics under different acetic acid loading rates

Abstract

Bioponic system is the use of organic substances in combination with hydroponic vegetable cultivation that reuses of nutrients in organic fertilizers to replace inorganic fertilizers used in hydroponic systems. There are microorganisms that can convert organic matter into usable forms of plants. In this study, we used Next-Generation Sequencing to look at bacterial communities and study the relationship between bacterial groups and phosphorus and COD concentrations by growing lettuce (Cos lettuce, 14 plants/system) in the bioponic system and acetic acid was added to the system (0 ml., 350 ml., 700 ml., 1050 ml.). The efficiency of phosphorus utilization (3.3%) was the highest and the heaviest yield was obtained at no acetic added condition (1194 g / 14 plants). Acetic acid addition (350 ml., 700 ml., 1050 ml.) did not make a difference in total phosphorus concentration, phosphate concentration, COD concentration and the transformation of phosphorus occurred in bioponic systems, with inorganic phosphorus contributing to plant growth through the linkage of microbial communities in plant roots and sediments. Although beneficial microbial communities in plant roots differed from those of sediment microbial communities, many microbes have been shown to be involved in the degradation of organic phosphorus and promote plant growth in bioponic systems. Those with acetic acid added and without acetic acid were found to have similar amounts of microorganisms (Phreatobacter, Clostridia). This indicates that the two systems have similar microbial communities. From the results of this study, it is possible to develop the efficiency of the bioponic system used in growing cos lettuce by avoiding high acetic acid developed/input to the bioponic systems.