Efeito do biofertilizante Agrobio no cultivo agroecológico de beterraba (Beta vulgaris L.)

Abstract

The use of biofertilizers in vegetable production is increasingly common among farmers, contributing to productivity and plant health. The biofertilizer Agrobio is produced from microbial activity in an open system on a substrate composed of water, fresh bovine manure, molasses, milk and mineral salts (micronutrients). The objective of the work was to evaluate the influence of Agrobio on the development of beetroot cultivated in the region of the North Coast of Bahia, municipality of Esplanada / BA, under agroecological management of production free of pesticides and soluble fertilizers). The beetroot seedlings were produced on polyethylene trays with 128 cells, supplied with a commercial substrate. Seeds from the cultivar Katrina were used, which were previously immersed in distilled water for 24 hours. Agrobio applications were carried out twice during the seedling development (6 and 13 days after sowing, DAS) and / or two or four applications after transplanting to the bedding area (14, 23, 30 and 85 days after transplanting, DAT). Five milliliters of Agrobio at 5% were applied to the collar region of the seedlings in the trays and plants at the bedding area. Three evaluations were carried out during the seedling phase, at 13, 20 and 30 DAS, and three after transplanting, at 14, 23 and 30 DAT. The following parameters were evaluated: height, number of leaves and leaf area; and, at the end of the cycle, the dry matter of the tuberous roots. The data obtained were submitted to the analyses: normality of residues (Shapiro-Wilk test), homogeneity of variances of residues (Bartlett test), variance (ANAVA at 5%) and comparison of means (Tukey test) at 5%. During the seedling phase, the application of Agrobio resulted in an increase of 50 and 75% at 30 DAS, respectively, in the height and number of leaves in relation to the control. In terms of leaf area during the same period, values were about eight times higher than those of the control. After transplanting, the application of the biofertilizer during the seedling phase promoted an increase in the height of the plants in relation to the control of about 60% whereas, the plants that received the biofertilizer just after transplanting, showed a smaller increase of about 20%. However, when applications were carried out in both phases, the results were superior to those resulting from the application in a single phase. At 92 DAT, the highest yields of tuberous roots were obtained after two applications during seedling development and four applications after transplanting, corresponding to an increase of around 60% in relation to the control. The presence of symptoms of gall-nematode (Meloidogyne spp.) infection was detected in the tuberous roots, but a visual evaluation revealed that the symptoms were more severe in the control plants, where the incidence was observed in all materials. The concomitant application of Agrobio in the seedling and plant from bedding area promoted a visual reduction of nematode incidence symptoms, which may be associated to the increased productivity observed. The biofertilizer Agrobio is capable of contributing to the productivity and quality of tuberous beet roots produced under agroecological management.