Variabilidade espacial da erodibilidade do solo em áreas de floresta nativa e plantios de bertholletia excelsa bonpl. No munícipio de Itacoatiara/AM

Abstract

Anthropic interventions in natural vegetation significantly modify soil properties, accelerating the degradation process and leading to the loss of fertile soils over large areas. Therefore, measuring the influence of different determining factors on the erosion process in order to estimate this loss is important. Thus, the erodibility that expresses, quantitatively, the susceptibility of the soil to erosion has aroused interest. This study allied to the principles of geostatistics allows a better visualization of the magnitude of soil losses. In an attempt to reduce erosion, forest cultivation presents itself as a viable alternative. In this context, in the Amazon region, the cultivation of the Brazil nut tree (Bertholletia excelsa) stands out. In view of the above, the present work aims to evaluate the dynamics of soil erodibility and its spatial variability in areas of native forest and in plantations of B. excelsa Bonpl. at different stages of development in the municipality of Itacoatiara-AM. The study was developed at Fazenda Aruanã, in three areas, two Brazil nut stands with ages of 3 and 25 years and one area of native forest. Samples were collected at a depth of 0.00-0.20 m, with 64 sampling points in each area, to determine soil texture and organic carbon, and thereby determine soil erodibility by the method of Denardin (1990) and Flanagan and Livingston (1995). When evaluating the area conversion, statistically, no effect on the overall erodibility of the soil was observed, showing that the implementation of this culture did not cause impacts on this attribute. In crops with a longer time of implantation, the same can increase or equal the MO contents of a native forest, thus favoring the quality of the soil. However, the cultivated areas presented a greater predisposition to suffer erosion betweenressulcos, on the other hand, the shear stress of the soil signaled resistance to the beginning of the erosive process. The geostatistics and the kriging maps helped in the understanding of the behavior of the erodibility factors, after the conversion process of native forest/cultivated areas.