Avaliação da sustentabilidade agroecológica dos sistemas agroextrativistas do açaí-do-amazonas (Euterpe precatoria Martius) Em Codajás

Abstract

Euterpe precatoria (Amazon açaí) is an abundant species in Codajás, Amazonas. With the increase in the demand for açaí, there is an increase in the production of açaí fruits, either through collection in extractive areas and/or through the expansion of its cultivation, requiring adequate management techniques to ensure the sustainability of production systems. The objective of this study was to evaluate the behavior of different management systems of the açaí-do-amazonas through indicators that can contribute to diagnose the agroecological sustainability of these systems. In this sense, to characterize the management systems of açaí plantations, socioeconomic, technological and environmental aspects were approached, through interviews with the application of a semi-structured questionnaire, with open and closed questions, addressing aspects of the family, property, income, management of açaí groves, marketing and environmental aspects. The evaluation of soil quality was carried out through chemical and physical properties (density and granulometry) and nutritional evaluation of the açaí trees, through foliar analysis. The analysis of variance was performed considering the model between and within treatments, which is similar to the analysis in a completely randomized design (DIC), with 4 management systems (extractive forest, managed forest, monoculture and intercropping) and 4 replications. The granulometry and chemical characterization data were evaluated through descriptive analysis and for foliar macro and micronutrients and physical attributes were subjected to analysis of variance, and the averages were compared by Tukey's test at the level of 5%. Correlation analysis (Pearson) and Principal Component Analysis (PCA) were performed. The sustainability assessment was performed using the Mulamba and Mock index. The results showed that açaí has great socioeconomic, cultural and environmental value for the population of Codajás, being the basis of the economy in the municipality. The management systems practiced by agroextractivists in Codajás have low dependence on external inputs and use traditional practices, with the input of organic material in the systems, as they take advantage of the remains of weeding and cultural remains from the collection of açaí fruits, with no standardization of management. . Forest management that has been practiced by agro-extractivists can be an alternative to increase the production of açaí fruits and reduce deforestation in the municipality, but it needs to be further studied. There is a great variability in the granulometric and chemical characteristics of the soils of the productive systems of the açaí-do-amazonas, mainly in the native açaí groves, however the most recurrent class was the silty loam, with higher proportions of the silt particle. In general, they are soils with high acidity, low levels of Ca, Mn and Zn and high availability of Fe at the two depths studied. Furthermore, at 0-10 cm depth, in some areas, such as extractive forest and managed forest systems, Mg, K and P contents were considered satisfactory for tropical soils. MO levels were considered medium to high. Although there are no suitable foliar concentration ranges for the açaí tree, the foliar nutrient concentrations of E. precatoria were compared with those of Euterpe oleracea, showing lower Ca and Zn concentrations; N, P and Mg were similar and K was similar to some studies and inferior to others. Fe was lower than those found for E. oleracea, but the concentrations found in native systems were higher than in monoculture. Mn concentrations were similar to some studies considered adequate, despite presenting limiting levels in the soil. No significant differences were observed for the physical attributes, organic carbon and carbon stock between the soils of the evaluated açaí systems, but they were considered adequate, presenting good physical quality, demonstrating the importance of organic matter management in these systems. Organic carbon content was positively correlated with total porosity and negatively correlated with soil density and relative density. The high acidity and low levels of Ca and Zn may be limiting fruit production in the studied systems. The results for leaf nutrient concentrations suggest that there are differences in the nutritional requirement for E. precatoria in reaction to E. oleracea. There is a selection pressure in the process of domestication of the species in relation to the natural environment. The extractive forest management system was considered the most sustainable system in relation to the chemical and physical attributes evaluated.