Soil water content is an important parameter in many engineering, agricultural and environmental applications. In practice, there exists a need to measure this parameter rather frequently in both time and space. However, common measurement techniques are typically invasive, time-consuming and labour-intensive, or rely on potentially risky (although highly regulated) nuclear-based methods, making frequent measurements of soil water content impractical. Here we investigate in the laboratory the effectiveness of four new low-cost non-invasive sensors to estimate the soil water content of a range of soil types. While the results of each of the four sensors are promising, one of the sensors, herein called the “AOGAN” sensor, exhibits superior performance, as it was designed based on combining the best geometrical and electronic features of the other three sensors. The performance of the sensors is, however, influenced by the quality of the sensor-soil coupling and the soil surface roughness. Accuracy was found to be within 5% of volumetric water content, considered sufficient to enable higher spatiotemporal resolution contrast for mapping of soil water content.

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As part of a unique tri‐nation study to commemorate the centenary of the iconic First World War ANZAC battlefield, this paper summarises the results of a laboratory experimental investigation of some geotechnical and geophysical characteristics of soil recovered from this field in Gallipoli, Turkey. The geophysical characterisation of these samples comprises the determination of the dielectric properties, namely real, imaginary and dielectric dispersion, over a frequency band between 200 MHz and 6 GHz. This characterisation is performed at the samples’ in situ state as well as in a controlled range of water content from oven‐dried to saturation. Specific frequencies pertaining to certain in situ geophysical applications and satellite surveys have been targeted as reference frequencies to study the dielectric data. Moreover, attenuation coefficients related to ground‐penetrating radar applications are also estimated at 200 MHz for a range of water contents. Microstructure and mineralogy were examined by environmental scanning electron microscopy and X‐ray diffraction techniques, respectively. Given the historical and archaeological significance of the ANZAC battlefield, these results can be used for future feasibility studies, planning, and result interpretation of geophysical investigations, including choosing the most appropriate time of the year and geophysical prospection tools, in this restricted‐access study area.

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