PHYSICAL SOIL QUALITY UNDER FOREST CONVERSION INTO AGROFORESTRY SYSTEM IN CENTRAL AMAZON

Abstract

Knowledge of soil physical quality in agroforestry systems in the Amazon region is crucial for understanding ecosystem changes and choosing conservation management approaches. This study aimed to assess the spatial variability and physical quality of the soil resulting from forest conversion into agroforestry systems in the Central Amazon. The research was conducted in the municipality of Silves, state of Amazonas, comparing a rural area under agroforestry cultivation (SAF) with an area of native forest (FN). Sampling grids of 70x70 m with one sampling site at every 10 m were established in both areas, totaling 64 sites. Soil samples were taken at depths of 0.00-0.10, 0.10-0.20, and 0.20-0.40 m. The physical properties evaluated included particle size analysis, macroporosity (MaP), microporosity (MiP), total porosity (Pt), soil bulk density (Ds), and soil resistance to penetration (RSP). Descriptive statistics and geostatistics were used for data analysis. The results indicated that the SAF area showed positive changes only for Ds and Pt, while the FN area exhibited the best conditions for MaP and RSP. Spatial dependence was observed for all properties at all depths, with range values greater than the grid spacing, ranging from 24.60 to 111.30 m for FN and 16.38 to 85.11 m for SAF.