Accounting for heterogeneity in the 𝛉–𝛔 relationship: Application to wheat phenotyping using EMI

A - Papers appearing in refereed journals

Blanchy, G., Watts, C. W., Ashton, R. W., Webster, C. P., Hawkesford, M. J., Whalley, W. R. and Binley, A. 2020. Accounting for heterogeneity in the 𝛉–𝛔 relationship: Application to wheat phenotyping using EMI. Vadose Zone Journal. 19 (1), p. e20037. https://doi.org/10.1002/vzj2.20037

AuthorsBlanchy, G., Watts, C. W., Ashton, R. W., Webster, C. P., Hawkesford, M. J., Whalley, W. R. and Binley, A.
Abstract

Geophysical methods, such as electromagnetic induction (EMI), can be effective for monitoring changes in soil moisture at the field scale, particularly in agricultural applications. The electrical conductivity (σ) inferred from EMI needs to be converted to soil moisture content (θ) using an appropriate relationship. Typically, a single global relationship is applied to an entire agricultural field; however, soil heterogeneity at the field scale may limit the effectiveness of such an approach. One application area that may suffer from such an effect is crop phenotyping. Selecting crop varieties based on their root traits is important for crop breeding and maximizing yield. Hence, high-throughput tools for phenotyping the root system architecture and activity at the field scale are needed. Water uptake is a major root activity and, under appropriate conditions, can be approximated by measuring changes in soil moisture from time-lapse geophysical surveys. We examine here the effect of heterogeneity in the θ–σ relationship using a crop phenotyping study for illustration. In this study, the θ–σ relationship was found to vary substantially across a field site. To account for this, we propose a range of local (plot specific) θ–σ models. We show that the large number of parameters required for these models can be estimated from baseline σ and θ measurements. Finally, we compare the use of global (field scale) and local (plot scale) models with respect to ranking varieties based on the estimated soil moisture content change.

KeywordsTheta; Sigma
Year of Publication2020
JournalVadose Zone Journal
Journal citation19 (1), p. e20037
Digital Object Identifier (DOI)https://doi.org/10.1002/vzj2.20037
Open accessPublished as ‘gold’ (paid) open access
FunderBiotechnology and Biological Sciences Research Council
Funder project or codeDesigning Future Wheat - WP1 - Increased efficiency and sustainability
Publisher's version
Output statusPublished
Publication dates
Print21 May 2020
Publication process dates
Accepted20 Apr 2020
PublisherSoil Science Society of America (SSSA)
ISSN1539-1663

Permalink - https://repository.rothamsted.ac.uk/item/9839z/accounting-for-heterogeneity-in-the-relationship-application-to-wheat-phenotyping-using-emi

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