Spatial variability of soil carbon stock in the Urucu river basin, Central Amazon-Brazil

Marcos Bacis Ceddia, André Luis Oliveira Villela, Érika Flávia Machado Pinheiro, Ole Wendroth

Research output: Contribution to journalArticlepeer-review

28 Scopus citations


The Amazon Forest plays a major role in C sequestration and release. However, few regional estimates of soil organic carbon (SOC) stock in this ecoregion exist. One of the barriers to improve SOC estimates is the lack of recent soil data at high spatial resolution, which hampers the application of new methods for mapping SOC stock. The aims of this work were: (i) to quantify SOC stock under undisturbed vegetation for the 0-30 and the 0-100cm under Amazon Forest; (ii) to correlate the SOC stock with soil mapping units and relief attributes and (iii) to evaluate three geostatistical techniques to generate maps of SOC stock (ordinary, isotopic and heterotopic cokriging). The study site is located in the Central region of Amazon State, Brazil. The soil survey covered the study site that has an area of 80km2 and resulted in a 1:10,000 soil map. It consisted of 315 field observations (96 complete soil profiles and 219 boreholes). SOC stock was calculated by summing C stocks by horizon, determined as a product of BD, SOC and the horizon thickness. For each one of the 315 soil observations, relief attributes were derived from a topographic map to understand SOC dynamics. The SOC stocks across 30 and 100cm soil depth were 3.28 and 7.32kg C m-2, respectively, which is, 34 and 16%, lower than other studies. The SOC stock is higher in soils developed in relief forms exhibiting well-drained soils, which are covered by Upland Dense Tropical Rainforest. Only SOC stock in the upper 100cm exhibited spatial dependence allowing the generation of spatial variability maps based on spatial (co)-regionalization. The CTI was inversely correlated with SOC stock and was the only auxiliary variable feasible to be used in cokriging interpolation. The heterotopic cokriging presented the best performance for mapping SOC stock.

Original languageEnglish
Pages (from-to)58-69
Number of pages12
JournalScience of the Total Environment
StatePublished - Sep 1 2015

Bibliographical note

Funding Information:
The authors acknowledge Petrobrás (Petróleo Brasileiro-SA) for the technical and financial support to perform this study (Contract-Petrobras/UFRRJ/FAPUR, N o . 0050.0036944.07.2 ). The authors thank the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico (CNPq: 249594/2013-7) and Coordenação de Aperfeiçoamento de Pessoal de Nivel Superior (CAPES: 1574-14-0) for the Pos Doctoral Scholarship granted to Drs. Ceddia and Pinheiro. Finally, the authors would also like to thank the reviewers for their valuable comments and suggestions.

Publisher Copyright:
© 2015 Elsevier B.V.


  • CTI
  • Heterotopic cokriging
  • Isotopic cokriging
  • Içá Formation

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution


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