Influência do magnésio sobre o desenvolvimento, produtividade e índices nitrogenados da batata semente básica, cultivada em substrato orgânico e em hidroponia

• Autor(a) principal: Barroso, Fernanda de Lima
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/4610
• topic: Magnésio; Batata semente básica; Hidroponia; Substrato orgânico; Magnesium; Potato foundation seed; Hydroponics; Organic substrate; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA

The purpose of this study was to evaluate the effect of magnesium dose (Mg) on morphological characteristics of the plant and production of potato tubercles in three cropping systems. Furthermore, this study aimed to select potential indices for the indirect diagnosis of the Mg state of the plant and for the prognosis of yield of basic seed potato tubercles. Each cropping system composed an experiment. At first, the treatments consisted of five doses of MgSO4 (0,0; 1,8; 3,6; 5,4 and 7.2 g dm-3) applied in organic substrate, in which were added the other nutrients, except nitrogen. The second experiment was identical to the previous, except that nitrogen was added to the substrate. In the third experiment, five doses of Mg (0,0; 0,625; 1,25; 2,5 and 5,0 mmol L-1) were tested in circulating and closed hydroponic system, in sand. The experiments were installed in a greenhouse, at the Plant Science Department at Federal University of Viçosa, simultaneously, in the period from 04/03/2012 to 06/25/2012. In experiments 1 and 2, it was used a commercial minitubercle of basic category, Ágata cultivar, as a propagating material. The plants were grown in pots of 3 dm3 containing commercial organic substrate. In experiment 3, it was used the sprout of Ágata cultivar as a propagating material. The plants were grown in pots of 8 dm3 containing washed sand, being the nutrients provided through nutrient solution. At 21 days after emergence (DAE), in the three experiments, the following characteristics were evaluated: plant height (PH), number of stems (NS), number of leaves (NL), fresh stems mass (FSM), fresh leaves mass (FLM), fresh root mass (FRM), dry stem mass (DSM), dry leaves mass (DLM), dry root mass (RDM), fourth leaf thickness (LT), fourth leaf length (LL), fourth leaf width (LW), number of leaflets of the fourth leaf (NLL), leaf area of the fourth leaf (LA), mass of fourth fresh leaf (FLM), mass of fourth dry leaf (DLM), numerical index (NI), nitrogen balance index (NBI), chlorophyll index (CHI), flavonols index (FLI), SPAD index (SPAD), N content in the fourth leaf (NC), Mg content in the fourth leaf (MgC). At 35 DAE, in the experiment in hydroponics, the following characteristics were evaluated: plant height (PH), number of leaves (NL), number of stems (NS), SPAD index (SPAD), nitrogen balance index (NBI) chlorophyll index (CHI) and flavonols index(FLI). The data were submitted to analysis of variance, regression and correlation. At 21 DAE, it was not observed visual symptoms of deficiency or excess Mg in plants, in the three experiments. Except the Mg content in the dry matter of the fourth leaf (MgC), any other characteristic evaluated at 21 DAE showed response to Mg dose in the three experiments. The doses that provided the highest production of tubercles, in units per plant, in the experiments 1, 2 and 3 were, respectively, 0,0; 7,2; g dm-3 of MgSO4 and 0.96 mmol L-1 of Mg2+ . With these doses, the Mg contents in the fourth leaf of dry matter were 2,02; 2,44 and 1,10 dag kg-1, respectively. The indices for indirect diagnosis state of Mg of plant depend on the cropping system utilized. It was not possible to determine any index, common to all three experiments, able to predict the production of tubercles in units per plant.