Soil Organic Carbon and Total Nitrogen Content in the Brazilian Amazon

Description

This dataset contains chemical and physical soil properties from 12 sites in the Brazilian Amazon (Pará), including 10 cacao-based agroforestry systems (CAFSs) and 2 secondary vegetation (SV) control areas. Soil samples were collected at four depths (0–10, 10–20, 20–30, and 30–40 cm) and analyzed for soil organic carbon (SOC), soil organic matter (SOM), total nitrogen (TN), C:N ratio, pH in water (1:2.5), and particle-size distribution (sand, silt, and clay), all expressed in g·kg⁻¹ where applicable. Each value represents the average of triplicate laboratory analyses from composite samples derived from five subsamples per depth and site. The dataset is provided in .xlsx and .csv formats, with columns identifying site ID, geographic coordinates, land-use type (CAFS or SV), soil depth, and all measured parameters. These data were used to assess the long-term impacts of cacao-based agroforestry on soil fertility and edaphic properties in highly weathered Amazonian soils.

Steps to reproduce

Soil samples were collected from 12 sites in the Brazilian Amazon at four depths (0–10, 10–20, 20–30, and 30–40 cm), using a Dutch auger in 100 m² sampling grids. A total of 240 individual subsamples (5 per depth × 4 depths × 12 sites) were collected and combined into 48 composite samples (one per depth and site). Samples were air-dried, sieved (2 mm), and analyzed in triplicate. Soil organic carbon (SOC) and total nitrogen (TN) were determined using dry combustion (Elemental Analyzer); soil organic matter (SOM) was calculated by multiplying SOC by 1.724. The C:N ratio was derived from SOC and TN values. Soil pH was measured in water (1:2.5 soil-to-water ratio). Particle-size distribution (sand, silt, clay) was assessed using the pipette method after pre-treatment with 1 mol·L⁻¹ NaOH and mechanical dispersion. All laboratory procedures followed the protocols of Teixeira et al. (2017) and Silva (2018), as cited in the main publication.

Institutions

• Universidade Federal do Para

  PA, Belem

Categories

Funders

• Coordenação de Aperfeicoamento de Pessoal de Nível Superior

  Ministry of Education

  Federal District, Brazil

Licence