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Research article - Peer-reviewed, 2016

Sensor mapping of Amazonian Dark Earths in deforested croplands

Söderström, Mats; Eriksson, Jan; Isendahl, Christian; Schaan, Denise; Stenborg, Per; Rebellato, Lilian; Piikki, Kristin

Abstract

Amazonian Dark Earths (ADEs) are fertile soils for agricultural production as well as important archaeological resources for understanding the pre-Columbian past of the Neotropical lowland rainforest. ADEs are threatened by expanding land exploitation and there is a need to develop efficient approaches to soil mapping and analysis for documenting these soils. In this paper we assess the potential of satellite remote sensing and proximal soil sensing to map, predict and monitor ADEs in land affected by agro-industrial development. We use instruments based on portable x-ray fluorescence (PXRF) and electromagnetic induction (EMI) as well as high-resolution satellite data (Spot 6) for detailed soil surveys at a 10-ha ADE site now mainly used for soybean production on the Belterra Plateau, Pará, Brazil. We predict the regional occurrence of ADE in a c. 250 km 2 test area centred on the known ADE site São Francisco using satellite data. Multivariate adaptive regression splines models were parameterised for predictions of soil organic carbon (SOC), cation exchange capacity (CEC), phosphorus (P) and depth of the A horizon in ADEs from sensor data - both from individual sensors and in sensor combinations. Combining sensors gave the best validation results: the highest modelling efficiencies (E) were 0.70 (SOC), 0.88 (CEC) and 0.74 (for both P and A depth). The most powerful single proximal sensor outputs in the predictions were Sr from the PXRF data and magnetic susceptibility (MSa) as measured by the EMI instrument. In the regional satellite based model we located 17 previously unrecorded ADE sites N2 ha. Ground control checks showed that 10 out of 11 sites were correctly classified. We conclude that these sensors are useful in studies of ADE in deforested cropland and provide new opportunities for detailed studies of the archaeological record.

Keywords

Terra preta; Remote sensing; Portable x-ray fluorescence; Electromagnetic induction; Soil classification; MARSplines

Published in

Geoderma
2016, volume: 281, pages: 58-68

Authors' information

Swedish University of Agricultural Sciences, Department of Soil and Environment
International Center for Tropical Agriculture
Swedish University of Agricultural Sciences, Department of Soil and Environment
Isendahl, Christian
University of Gothenburg
Schaan, Denise
Federal University of Pará
Stenborg, Per
University of Gothenburg
Rebellato, Lilian
Federal University of Western Pará
Piikki, Kristin (Persson, Kristin)
Swedish University of Agricultural Sciences, Department of Soil and Environment
Piikki, Kristin (Persson, Kristin)
International Center for Tropical Agriculture (CIAT)

Sustainable Development Goals

SDG15 Life on land

UKÄ Subject classification

Soil Science
Archaeology
Remote Sensing

Publication Identifiers

DOI: https://doi.org/10.1016/j.geoderma.2016.06.024

URI (permanent link to this page)

https://res.slu.se/id/publ/77636