Utilização de leguminosa (Gliricidia sepium) em consórcio com coqueiro híbrido

Abstract

Brazil stands out in the production of tropical fruits, among which is the coconut. The northeast region, with emphasis on the states of Ceará and Bahia, appears as one of the main productive centers of the country. The search for a more competitive and sustainable production means that alternatives to the use of mineral fertilizers, such as the use of nitrogen fixing legumes, are increasingly desired. In this work the objective was to evaluate the initial development of Gliricidia sepium and its effects on soil attributes by planting at different spacings in consortium with the coconut. The study was carried out in Fazenda Aguapé, belonging to Ducoco Litoral S.A, in the municipality of Itarema-CE, with an experiment installed in randomized blocks with 4 replicates. For the germination and plant growth rate measures (height and diameter), the evaluated treatment consisted of three planting spacings (1x1m, 1x0,5m, 1x0,25m). For the root attributes (total root volume, total root area, mean root diameter) and soil chemical attributes (total organic carbon and total nitrogen) was considered a 3x4 factorial in which the first treatment factor consisted of the three spacings already mentioned, and the second factor was constituted by four sampling depths (0-10,10-20,20-30,30-40 cm). The germination rate was evaluated at 60 days after sowing, plant growth measurements were performed at 7 months after sowing, while soil and root samples of the plants were collected 9 months after sowing. The roots were analyzed using the SAFIRA program and the statistical analyzes were done using the Sisvar program. There were no statistical differences in relation to germination parameters, total root area, total root volume and mean root diameter between the spacings. However, the most superficial layer (0-10cm) presented the highest values for total area of roots and total volume of roots. The variables carbon and nitrogen had the highest values in the layer 0-10cm, however did not differ between the spacings. The diameter of the plants did not differ between treatments, however at the time higher values were observed for the plants cultivated in the 1x1m spacing. The use of Gliricidia sepium intercropped with the coconut hybrid PB 121 has benefits to the soil contributing C and N in the most superficial layers, being able to be cultivated with spacings ranging from 1x1 to 1x0,25m that bring similar benefits. Further studies are needed to identify the effects of the legume as a green manure, that is, after crushing the shoot biomass and incorporating it into the soil.