TY - JOUR
T1 - Impact of charring on cereal grain characteristics: linking prehistoric manuring practice to 15N signatures in archaeobotanical material
AU - Kanstrup, Marie
AU - Thomsen, Ingrid Kaag
AU - Mikkelsen, Peter Hambro
AU - Christensen, Bent Tolstrup
PY - 2012
Y1 - 2012
N2 - Systematic use of animal manure has been demonstrated to be detectable in the plant δ15N value but evidence of manure affecting isotopic composition is mainly based on studies of fresh plant material. These findings can potentially be applied to archaeobotanical assemblages and thus provide information about prehistoric manuring practice. Prehistoric grains are generally found in a charred state of which the exact charring conditions are unknown but most likely often multifarious. In this study we examined the influence of grain weight and a range of charring conditions with regards duration, temperature, oxygen availability, and manuring. The charring was applied to emmer, spelt and naked barley with assessment of weight loss, N concentration and δ15N. There were only small and non-systematic variations in δ15N in relation to grain weight class. We also found that charring did not distort δ15N in either a systematic or substantial way and conclude that manuring most likely will be detectable in archaeobotanical charred grains. As certain within-grain variability in δ15N existed, especially in the intensively manured grains, the resolution of this kind of information should be carefully considered. However, despite attempts to deliberately tamper and distort the grain δ15N signature, the changes observed in this study were too small to be of any consequences for the archaeobotanical applicability of the method. Thus the isotope method offers unique evidence about prehistoric manuring practice.
AB - Systematic use of animal manure has been demonstrated to be detectable in the plant δ15N value but evidence of manure affecting isotopic composition is mainly based on studies of fresh plant material. These findings can potentially be applied to archaeobotanical assemblages and thus provide information about prehistoric manuring practice. Prehistoric grains are generally found in a charred state of which the exact charring conditions are unknown but most likely often multifarious. In this study we examined the influence of grain weight and a range of charring conditions with regards duration, temperature, oxygen availability, and manuring. The charring was applied to emmer, spelt and naked barley with assessment of weight loss, N concentration and δ15N. There were only small and non-systematic variations in δ15N in relation to grain weight class. We also found that charring did not distort δ15N in either a systematic or substantial way and conclude that manuring most likely will be detectable in archaeobotanical charred grains. As certain within-grain variability in δ15N existed, especially in the intensively manured grains, the resolution of this kind of information should be carefully considered. However, despite attempts to deliberately tamper and distort the grain δ15N signature, the changes observed in this study were too small to be of any consequences for the archaeobotanical applicability of the method. Thus the isotope method offers unique evidence about prehistoric manuring practice.
U2 - 10.1016/j.jas.2012.03.007
DO - 10.1016/j.jas.2012.03.007
M3 - Journal article
SN - 0305-4403
VL - 39
SP - 2533
EP - 2540
JO - Journal of Archaeological Science
JF - Journal of Archaeological Science
IS - 7
ER -