The Middle and Lower Yangtze valley is recognized as the earliest centre of rice agriculture. Rice cultivation, alongside the utilization of various starchy plants, has persisted over millennia since the early Neolithic. While previous discussions have extensively explored the use of nuts, tubers, and large-grain grasses, small-grain grasses have received relatively little attention. This study examines plant impressions found in pottery sherds dating to the early Shangshan period (ca. 12,711–8,538 cal bp) to shed light on the significance of barnyard grass (Echinochloa sp.) during this era. Using microCT technology, we obtained clear and detailed visualizations of plant remains from pottery sherds, enhancing the archaeobotanical assemblage in a context where macro plant remains were scarce. Our study provides compelling evidence of diversified cultivation practices in the Lower Yangtze valley during the early Neolithic period. Furthermore, it situates the origins of rice agriculture within the broader framework of wetland plant management.