Growth and quality of lisianthus [Eustoma grandiflorum (Shinn.)] cultivated in rice husk substrates in troughs with leaching recirculation

This study aimed to evaluate the growth and quality of lisianthus cultivated in different rice husk substrates. The evaluated substrates were: carbonized rice husk (CRH; 100%); raw rice husk (RRH; 100%); CRH (70%) + S10 Beifort® commercial organic compost (30%); and RRH (70%) + S10 Beifort® commercial organic compost (30%). Plant dry mass (DM) production and partitioning, plant leaf area and shoot/root DM ratio were analyzed. Quality parameters of the flower stems were also evaluated (length; diameter and number of flowers and buds). The RRH substrate at 100% reduced plant growth and prevented flower development. This modified dry mass partitioning among the plant organs. The substrates RRH + S10 and CRH provided quality flower stems. Thus, both substrates can be used to produce cut lisianthus flowers in recirculating nutrient systems. However, the RRH + S10 substrate stood out because it increased plant growth. This result is ascribed to the improvement of the physical and chemical properties of substrate RRH + S10 as a result of the presence of both the organic compost, which benefited the water holding capacity, and the RRH, which guaranteed high porosity to the substrate.