Changing growing conditions for crops during the Near Eastern Bronze Age (3000–1200 BC): the stable carbon isotope evidence

An investigation into the archaeological application of carbon stable isotope analysis used to establish crop water availability: solutions and ways forward

“…As a possible solution to these issues, researchers have started contrasting carbon isotope discrimination data for a number of different plant species from the same archaeological site. The aim is to identify differences in Δ between these crops which could then be explained in terms of differences in irrigation and crop management techniques (Araus et al, 1997b;Ferrio et al, 2005;Riehl et al, 2008). In relation to this, Ferrio et al (2005) proposed comparing isotope data from major food crops with the remains of non-cultivated plants such as trees or with cultigens which are relatively well adapted to arid conditions and are therefore unlikely to have received any irrigation (see also Ferrio et al, 2005Ferrio et al, , 2006.…”

“…In relation to this, Ferrio et al (2005) proposed comparing isotope data from major food crops with the remains of non-cultivated plants such as trees or with cultigens which are relatively well adapted to arid conditions and are therefore unlikely to have received any irrigation (see also Ferrio et al, 2005Ferrio et al, , 2006. Following this suggestion, Riehl et al (2008) used Δ values for barley as baseline data for non-irrigated crops. They combined these data with the results of climate modelling to infer that irrigation was practised at some of the investigated sites.…”

“…They combined these data with the results of climate modelling to infer that irrigation was practised at some of the investigated sites. While the strategies employed to detect irrigation through carbon stable isotope signals of plants are therefore relatively sophisticated, all researchers concede that the trends observed in their datasets may well be explained by differences in the growing cycles or water use efficiency of individual species rather than by any water management strategies employed by humans (Ferrio et al, 2005;Riehl et al, 2008).…”

“…Carbon stable isotope analysis of archaeological cereals is a relatively new approach for the investigation of ancient irrigation systems (Araus and Buxo, 1993;Araus et al, 1997b;Ferrio et al, 2005;Araus et al, 2007;Riehl et al, 2008). The approach relies on the basic principle that plants under water stress discriminate less against the 'heavier' carbon-13 ( 13 C) isotope than plants whose water requirements are fully met (Farquhar and Richards, 1984;Farquhar et al, 1989).…”

“…They concluded that the southeast had been consistently drier than the northeast and that, although climate was generally wetter than today, there was a trend towards more arid conditions throughout the periods studied (see also Araus et al, 2003). More recently, Riehl et al (2008Riehl et al ( , 2009) demonstrated that stable carbon isotopes in plants record broad-spectrum environmental changes. The main focus of Riehl et al (2009) was to assess the reliability of pedogenic carbonates from southeastern Turkey as palaeoenvironmental indicators.…”