Épocas de aplicação e doses de nitrato de cálcio em alface americana

Abstract

Lettuce is the most consumed vegetable leafy in the world and its cultivation requires laborintensive, thus demonstrating its social importance. This study aimed to evaluate the productivity of crisphead lettuce subjected to fertilization with calcium nitrate at different doses and two application times. The experiment was conducted on site in the city of Catalão, Goiás state. The experimental design was randomized blocks, in a factorial 2 x 5, two application periods, being the 1st time (50% of the dose at transplanting and 50% at 20 days after transplanting) and the 2nd time (50% at 10 days after transplanting and 50% at 20 days after transplanting) and five calcium nitrate doses (0, 150, 300, 450 and 600 kg ha-1), with 4 replicates. The plots consisted of 1.0 x 1.2 m, with four rows with four plants each arranged in the spacing 0.25 x 0.30 m, totaling 16 plants per plot. The following evaluations were performed: number of internal and external leaves, head height, head diameter, height and head diameter ratio, compactness, stem diameter, chlorophyll content, commercial production, nitrogen content in the leaf and internal and external calcium content of internal and external sheet. Data were subjected to analysis of variance (F test) and the averages compared by Tukey test at 5% probability for application times, for calcium nitrate doses were conducted regression analysis. The application of calcium nitrate in the 2nd season positively influenced the phytotechnical features in the culture of lettuce. As for the calcium nitrate doses there was an increase for the characteristics evaluated in the culture of lettuce.