Crop water status from plant stable carbon isotope values: A test case for monsoonal climates
journal contributionposted on 2023-05-20, 21:21 authored by Penelope JonesPenelope Jones, O'Connell, TC, Jones, MK, Singh, RN, Petrie, CA
Stable carbon isotope analysis is increasingly used in archaeology as an indicator of crop water status and/or water management regime. While the technique shows promise, robust modern baseline studies are required to inform and validate archaeological interpretations. Here, we test stable carbon isotope values as a crop water status proxy in a monsoonal climatic context for the first time. Specifically, we test the relationship between grain stable carbon isotope values (δ13Cgrain), water availability, irrigation and soil type in barley (Hordeum vulgare L. (Zohary and Hopf.)) in north-west India, with the aim of deriving a locally-appropriate model for isotopic interpretation. We test this relationship across a substantial rainfall gradient (200–1000mm/year) and find a negative logarithmic relationship between climatic water availability and δ13C. However, there is significant noise in the relationship, and we report δ13Cgrain variation of over 3‰ amongst samples drawn from similar climatic contexts. Soil type, irrigation type and irrigation frequency have no clear modifying effects. We conclude that: (1) barley stable carbon isotope values can act as an archaeological water status proxy in monsoonal areas, but will be most sensitive in areas receiving <450mm rainfall per year; and (2) it is not possible to precisely infer water management regimes. On the basis of our results, we propose guidelines for archaeological barley stable carbon isotope interpretation in north-west India and analogous monsoonal climates.
Publication titleThe Holocene
Department/SchoolMenzies Institute for Medical Research
Place of publicationHodder Headline Plc, 338 Euston Road, London, England, Nw1 3Bh
Rights statement© The Author(s) 2021. This article is distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 License (https://creativecommons.org/licenses/by-nc/4.0/) which permits non-commercial use, reproduction and distribution of the work without further permission provided the original work is attributed as specified on the SAGE and Open Access page (https://us.sagepub.com/en-us/nam/open-access-at-sage).