Atributos físicos e químicos de solos cultivados com bananeiras no brejo paraibano

Abstract

Reducing the soil quality through inadequate soil management can accelerate its degradation and the depletion of natural resources in the agroecosystem with negative impacts on agricultural yield. Here we studied the socioeconomic diagnosis of the banana crop systems (Musa spp. L.) and, we evaluated its influence on soil physical and chemical attributes under field conditions. So, to achieve these two objectives we used the following approaches: (i) We applied a semi-structured questionnaire for the socioeconomic diagnosis of banana crop systems. Twenty farmers were interviewed in 5 countryside communities from 2 different regions (N = 150) and this database was evaluated through descriptive analysis. (ii) We collected soil samples from 2 layers (0-20 and 20-40 cm) and 3 slope hill positions (summit, backslope and toeslope) in the banana crop systems. For comparison purposes, soil samples were also collected in areas with native vegetation under the Atlantic Forest domain. Data were submitted to two-way ANOVA and the means were compared by the Tukey post-hoc test at 5% probability. Based on the results obtained in our socioeconomic diagnosis, we observed that all studied areas can be classified as family-based production system. Among the agricultural activities practiced within these areas, we found that the banana crop system was the main source of income. The low banana yield of the study areas could be related to: (1) the low level of technology employed; (2) inadequate or non-existent management of weeds, pests and diseases; and (3) inadequate soil management. For the effects of banana crop systems on physical and chemical attributes, bulk density and clay content increased as a function of the layers and slope positions. Among the studied areas, no significant differences were observed in the surface layer for the sand content, soil macro and microporosity, and available water. Regarding slope positions of the relief, it was observed that in the toeslope there was an increase in sand content, total porosity and available water, and a reduction of clay content. In the areas under banana crop systems, we observed an increase of CTCef, CTCpH7 and sum of bases, despite the low values of K+, Ca+2, Na+ and base saturation. There was a tendency of pH increase and reduction of H++ Al3+, Al3+ and aluminium saturation from top to bottom in the areas under forest. In the soil surface layer there was an increase in pH, x Ca and organic carbon. Banana crop systems influenced the physical attributes, which favoured soil water retention.