Chemical attributes of the soil under different uses and coverages in the context of family agriculture

Abstract

The transition from native vegetation to monoculture agricultural systems and the advance of degraded pasture areas in the Amazon pose challenges, especially with regard to the maintenance of desirable soil conditions. Therefore, there is a need for researches approach understanding of soil conditions under its different uses and coverage, as they are essential to promote environmental sustainability. Thus, this study evaluated soil chemical attributes under different systems (Secondary Forest, Pasture and SAF), at three depths (0-5cm, 5-10cm and 10-20cm), in family farmers' areas in the Abril Vermelho Settlement at Santa Bárbara of Pará, PA. The evaluated chemical attributes were: soil pH, calcium (Ca2+), magnesium (Mg2+), potassium (K+), available phosphorus (P), exchangeable aluminum (Al3+) acidity potential (H + Al) and organic matter (MO), and through these quantified the values of sum of bases (SB), base saturation (V%), aluminum saturation (m%), effective cation exchange capacity and pH 7. The data were found in the analysis of variance (ANOVA) and later as means of the attributes were compared to the Tukey test (SISVAR 5.6). The results were subjected to multivariate analysis by Principal Component Analysis (PCA). As a result, it was obtained that most of the chemical attributes of the soil differed clinical (p <0.05). The evaluated SAF was the land use and cover system that presented the highest averages of pH, Ca2+, Mg2+, SB and V% and the lowest H + Al, Al3+ and m%. The PCA of the variables corroborated the results of comparison of means, showing that there was a distinction between the systems by coverage and depth evaluated, mainly for SAF, which was the best distinguished from the other systems by the attributes pH, Ca2+, Mg2+, SB and V%. Thus, demonstrating that the SAF together with the management applied in the area provided improvements in the chemical quality of the soil.