Electrical resistivity tomography to measure and monitor hydrodynamic heterogeneities in a Malawian agricultural alfisol

Swift, R.; Boyd, J.; Chambers, J.; Wilkinson, P.; Sandram, I.; Magwero, N.; Gregory, A.; Whalley, R.; Meldrum, P.; Chimungu, J.; Inauen, C.; Harrison, H.; Nalivata, P.; Nguyen, F.; Lark, M.

Abstract

Conservation Agriculture (CA) is an agricultural method that has been shown to provide crop resilience to drought. In order to better understand the hydrodynamics in soils cultivated using CA, we installed geophysical monitoring equipment and co-located pedophysical point sensors. Cross-borehole Electrical Resistivity Tomography (ERT) monitoring datasets from Chitedze Agricultural Research Station, Lilongwe, Malawi, are discussed alongside sensor derived moisture content data.

We have revealed a complex spatiotemporal pattern of near surface moisture dynamics that would be difficult to characterise using point sensors alone, and observe some differences between soils under CA and those farmed conventionally. Additionally, a varying relationship between moisture content and electrical resistivity is discovered with increasing depth. Ongoing work includes developing ERT derived soil moisture estimates - potentially using multiple relationship models for differing depths - and analysing these thoroughly to better understand how hydrodynamics in CA treated soils differs from soils tilled conventionally.

Citation

Swift, R., Boyd, J., Chambers, J., Wilkinson, P., Sandram, I., Magwero, N., Gregory, A., Whalley, R., Meldrum, P., Chimungu, J., Inauen, C., Harrison, H., Nalivata, P., Nguyen, F., & Lark, M. (2023, September). Electrical resistivity tomography to measure and monitor hydrodynamic heterogeneities in a Malawian agricultural alfisol. Presented at 2nd Conference on Hydrogeophysics 2023, Held at Near Surface Geoscience Conference and Exhibition 2023, NSG 2023, Edinburgh, UK

• Presentation Conference Type: Edited Proceedings
• Conference Name: 2nd Conference on Hydrogeophysics 2023, Held at Near Surface Geoscience Conference and Exhibition 2023, NSG 2023
• Start Date: Sep 3, 2023
• End Date: Sep 7, 2023
• Acceptance Date: Aug 7, 2023
• Online Publication Date: Aug 8, 2023
• Publication Date: 2023-09
• Deposit Date: Sep 30, 2023
• Book Title: NSG2023 2nd Conference on Hydrogeophysics, Volume 2023
• ISBN: 9789462824621
• DOI: https://doi.org/10.3997/2214-4609.202320106
• Public URL: https://nottingham-repository.worktribe.com/output/24138992
• Publisher URL: https://www.earthdoc.org/content/papers/10.3997/2214-4609.202320106