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

The lisianthus production for cut flowers on substrate arranged in troughs with leaching recirculation can represent a new crop system for reducing the incidence of soil pathogens and improving flowers quality. In this sense, effects of the growing substrate on the crop should be known, especially because information about lisianthus growth is incipient. The study aimed to evaluate the growth and quality of the lisianthus cultivated on 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 (30%). Plant dry mass (DM) production and partitioning, plant leaf area and shoot/root DM ratio were analysed. Quality parameters of flower stems were also evaluated (length; diameter and number of flowers and buds). The RRH substrate at 100% reduced plant growth and refrained flowers development. This modified dry mass partitioning among plant organs. The substrates RRH + S10 and CRH provided high quality flower stems. Thus, both substrates can be used to produce cut flowers of lisianthus in recirculating nutrient system. However, the RRH + S10 substrate stood out because it increased the plant growth. This result is ascribed to the improvement of the physical and chemical properties of the substrate RRH + S10 due to the presence of both, the organic compost, that benefited the water holding capacity, and the RRH which guaranteed a high porosity to the substrate.