Evaluación de un sistema de recirculación automática de drenajes en el cultivo de rosa, en términos de S, Na+ y Cl-

In Colombia, mixtures of substrates such as burned rice husk (BRH) and coconut fiber (CF) are used for the cultivation of cut flowers. Fertigation is applied to ensure 30% drainage, which can contaminate water and soil. In a drainage recycling system, there is a tendency for ions that are poorly absorbed by plants, such as sodium and chloride, to accumulate, which can create an ionic imbalance in the solution or salinize the substrate. An automatic drainage recycling system was built in rose cv. ‘Charlotte’ established in mixtures 100BRH, 65BRH:35CF, and 35BRH:65CF with 0%, 50%, and 100% drainage recycling. The contents of S, Na+, and Cl- were evaluated in drainages, substrates, and plant tissue at 0, 5, and 8 weeks after pruning (WAP). The SO42- and Na+ ions presented a similar behavior over time, with contents significantly higher in the substrates with higher CF contents at 0 WAP and the opposite at 8 WAP. In addition, the higher the BRH content and the recycling percentage, the higher the SO42- in the drains. There was no significant difference in the S contents in substrates and plant tissue. Drainage recycling (50% and 100%) significantly increased Na+ contents in the substrate. The Cl- concentrations were significantly different at 8 WAP, being higher in treatments with recycling (50% and 100%), regardless of the type of substrate mixture.