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Research article - Peer-reviewed, 2016

Performance Evaluation of Proximal Sensors for Soil Assessment in Smallholder Farms in Embu County, Kenya

Piikki, Kristin; Söderström, Mats; Eriksson, Jan; John, Jamleck Muturi; Muthee, Patrick Ireri; Wetterlind, Johanna; Lund, Eric

Abstract

Four proximal soil sensors were tested at four smallholder farms in Embu County, Kenya: a portable X-ray fluorescence sensor (PXRF), a mobile phone application for soil color determination by photography, a dual-depth electromagnetic induction (EMI) sensor, and a LED-based soil optical reflectance sensor. Measurements were made at 32-43 locations at each site. Topsoil samples were analyzed for plant-available nutrients (N, P, K, Mg, Ca, S, B, Mn, Zn, Cu, and Fe), pH, total nitrogen (TN) and total carbon (TC), soil texture, cation exchange capacity (CEC), and exchangeable aluminum (Al). Multivariate prediction models of each of the lab-analyzed soil properties were parameterized for 576 sensor-variable combinations. Prediction models for K, N, Ca and S, B, Zn, Mn, Fe, TC, Al, and CEC met the setup criteria for functional, robust, and accurate models. The PXRF sensor was the sensor most often included in successful models. We concluded that the combination of a PXRF and a portable soil reflectance sensor is a promising combination of handheld soil sensors for the development of in situ soil assessments as a field-based alternative or complement to laboratory measurements.

Keywords

East Africa; proximal sensor; soil assessment; subsistence farming

Published in

Sensors
2016, volume: 16, number: 11, article number: 1950

Authors' information

Piikki, Kristin (Persson, Kristin)
International Center for Tropical Agriculture (CIAT)
Piikki, Kristin (Persson, Kristin)
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
Swedish University of Agricultural Sciences, Department of Soil and Environment
John, Jamleck Muturi
University of Embu (UoEm)
Muthee, Patrick Ireri
Ministry of Agriculture
Swedish University of Agricultural Sciences, Department of Soil and Environment
Lund, Eric
Veris Technologies

UKÄ Subject classification

Soil Science

Publication Identifiers

DOI: https://doi.org/10.3390/s16111950

URI (permanent link to this page)

https://res.slu.se/id/publ/78001