Comparing apparent electrical conductivity measurements on a paddy field under flooded and drained conditions

• Published in: Precision agriculture Vol. 13; no. 3; pp. 384 - 392
• Main Authors: Islam, Mohammad Monirul, Meerschman, Eef, Saey, Timothy, De Smedt, Philippe, Van De Vijver, Ellen, Van Meirvenne, Marc
• Format: Journal Article
• Language: English
• Published: Boston Springer-Verlag 01.06.2012; Springer US; Springer Nature B.V
• Subjects: Agriculture; Atmospheric Sciences; Biomedical and Life Sciences; Chemistry and Earth Sciences; Computer Science; Crop science; drainage; drained conditions; electrical conductivity; floodplains; growing season; Life Sciences; Moisture content; paddies; physicochemical properties; Physics; Remote Sensing/Photogrammetry; Rice; sand; Sensors; soil management; Soil Science & Conservation; Soil testing; soil texture; soil water; Statistics for Engineering; Studies; surface water; surveys; value added; Wetlands; Bangladesh; Electromagnetic induction sensor; Paddy field; EM38; Within-field spatial variation
• ISSN: 1385-2256; 1573-1618
• DOI: 10.1007/s11119-011-9253-2

Every growing season, paddy fields are kept both flooded and drained for a significant period of time. As a consequence, these soils develop distinct physico-chemical characteristics. For practical reasons, these soils are mostly sampled under dry conditions, but the question arises how representative the results are for the wet growing conditions. Therefore, the apparent electrical conductivity (ECa) of a 1.4 ha alluvial paddy field located in the Brahmaputra floodplain of Bangladesh was measured in both dry and wet conditions by a sensing system using the electromagnetic induction sensor EM38, which does not require physical contact with the soil, and compared both surveys. Due to the smooth water surface under wet conditions which ensured increased stability of the sensing platform, the results of the survey showed considerably reduced micro-scale variability of ECa. Furthermore, the wet survey results more reliably furnished soil-related information mainly due to the absence of soil moisture dynamics. The differences between ECa under wet and dry conditions were attributed to differences in soil texture, mainly the sand content variation having considerable effect on soil moisture differences when flooded following drainage. Accordingly, the largest differences between ECa under wet and dry conditions were found in those parts of the field with a large sand content. Hence, the conclusion was that an ECa survey on flooded fields has an added value to precision soil management.