Spatial variability of soil organic carbon in native forest and agroforestry system in central Brazilian Amazonia

The intensified emission of greenhouse gases due to anthropogenic activities may drastically change the climate and reduce natural resource availability. In this context, conservation systems, such as agroforestry systems, can mitigate GHG emissions and allow the sustainable use of natural resources while maintaining ecological processes and economic and social development. We aimed to evaluate the spatial variability in bulk density, soil organic carbon, and SOC stocks in AFS and native forest sites in the Brazilian Amazon. The study sites are located in the municipality of Silves, state of Amazonas. We sampled one AFS site and one NF site in three layers of depth (0-0.1 m, 0.1-0.2 m, and 0.2-0.4m) in sampling grids with 64 equally interspaced sampling points. We analyzed soil traits using descriptive statistics and geostatistics. The AFS implemented 22 years before data collection in the study site contributed to the conservation of SOC stocks. Bulk density was similar between the AFS and the NF in all layers, indicating the absence of negative impacts of the AFS and possibly the recovery and maintenance of environmental quality in the previously disturbed study site. Both the AFS and the NF sites presented strong spatial dependence. Spatial patterns of SOC in the AFS may allow the definition of distinct management zones. The information provided by the geostatistical tools can be used by family farmers and managers of AFS in the region.