Evaluating Water Fertilizer Coupling on the Variations in Millet Chaff Size during the Late Seventh Century in Northwest China: Morphological and Carbon and Nitrogen Isotopic Evidence from the Chashancun Cemetery

Stable isotopic analyses of the remains plants that have been unearthed from archaeological sites are often featured as key indicators crop cultivation and living environment. However, systematic archaeobotanical studies not applied widely in Chinese historical sites, especially those Tang dynasty. This paper aims to use carbon nitrogen reveal potential influence water fertilizer conditions on size millet chaffs were excavated Chashancun cemetery. To achieve this, >3600 uncharred broomcorn foxtail chaff measured. Furthermore, 30 samples selected analyze isotopes, respectively. The widths thicknesses ranged 1.11 2.38 mm 0.95 2.24 mm, respectively, while 1.94 0.69 1.90 δ13C δ15N values −13.0‰ −12.0‰ 15.7‰ 17.8‰, −14.0‰ −12.9‰ 18.8‰, results show correlations between carbon/nitrogen values, suggesting might significantly affected grain yield during late seventh century northwestern China.