Hidroponia modificada e espuma fenólica como inovações tecnológicas no enraizamento e crescimento de estacas de Coffea arabica L.

Abstract

Brazilian coffee is an important activity in the agricultural sector of the country and therefore requires innovative technologies for the production of seedlings, which is one of the most important inthe implementation of crops. Thus, the cloning of plants by cutting, mineral nutrition via modified hydroponics and the use of alternative substrates emerge as technological innovations for seedling production. The objective of this work was to evaluate the production of clonal coffee seedlings in a modified hydroponic system compared to the conventional system of air-conditioned greenhouse, using vermicusite and phenolic foam as alternative substrates; in a second assay evaluate the transfer of cuttings from the conventional system to the modified hydroponics system. The experiments were conducted at the Department of Agriculture of UFLA. Both experiments were carried out in a completely randomized design, the first being in a 2x2 factorial system: two seedling production systems (conventional and modified hydroponic), and two substrates (tubes containing vermicusite and phenolic foam); and the other with 5 treatments, these being the transfer times after stake (Testemunha, 0DAE, 25DAE, 50DAE and 75DAE). Evaluations of survival, growth, roots, weight of plant dry matter, total leaf area, growth, physiological and stomata characteristics were performed. The data were processed and analyzed by the SISVAR®. Seedlings produced in phenolic foam do not survive in the modified hydroponics environment. The seedlings produced in a modified hydroponic system present lower survival, however they present greater growth of shoots and root system in relation to the seedlings of the conventional system. The highest growth of seedlings in hydroponic system is able to anticipate the transplanting of these to the field in 52 days. The weight of the dry matter of the roots is similar in the two substrates although in the conventional system they have greater volume and length. Chlorophyll a, b and total contents are lower in seedlings produced in phenolic foam, which presented adaptations to the drying of the phenolic foam surface. The cuttings placed to root directly in modified hydroponic system survived less, but presented higher total height, number of leaves, volume, surface area and root length, dry matter weight. The seedlings of this treatment also had higher total leaf area and better growth rates, as well as higher chlorophyll a, b and total contents and desirable physiological characteristics. It was concluded, therefore, that the innovative modified hydroponics system promotes greater growth of coffee seedlings produced by stofa in tubes with vermicuitis in relation to those produced in conventional system. The substrate "phenolic foam" can be used alternatively in the air-conditioned greenhouse system, but in the modified hydroponics system it is not indicated because it promotes total mortality of the seedlings. Coffee cuttings should be placed to root directly in the hydroponic system.