Behavior of NPK in carnation (Dianthus caryophyllus L.) cv. Delphi growing on a soilless crop system with recycling of drainage

In the soilless system crop of Colombian floriculture, the carnation cut flower is one of the most representative. The aim of this study was to determine the content of N, P, and K in the substrates based on burned rice husk (BRH) and coconut fiber (CF), in leachates, and in the tissue of the whole carnation plant, with three percentages of recycling. The study was carried out under greenhouse conditions, with standard carnation cv. Delphi planted at a density of 24.3 plants/m(2), fertigated through a computerized system and an automatic drainage recycling system. A randomized complete block experimental design in a split-plot with nine treatments and three replications was used. The concentration of nitrate in the leachate was influenced by recycling levels, and that of the ammonium ion by the substrate with the highest BRH content; the percentage of N in the substrate decreased significantly with the increase in the BRH content. Phosphate content in the leachate was significantly higher in the treatment with 100% recycling and with the increase in the percentage of CF in the substrate; in the substrate, the P content also increased as a function of the increase in the percentage of CF. The concentration of the K in the leachate was significantly higher in the treatments without recycling and with a higher percentage of BRH; a significantly higher content of K is highlighted in the substrates with higher CF content.