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The sowing date and density are considered to be the main factors affecting crop yield. The determination of the sowing date and sowing density, however, is fraught with uncertainty due to the influence of climatic conditions, topography, variety and other factors. Therefore, it is necessary to find a comprehensive consideration of these factors to guide the production of winter rapeseed. A reliable crop model could be a crucial tool to investigate the response of rapeseed growth to changes in the sowing date and density. At present, few studies related to rapeseed model simulation have been reported, especially in the comprehensive evaluation of the effects of sowing date and density factors on rapeseed development and production. This study aimed to evaluate the performance of the AquaCrop model for winter rapeseed development and yield simulation under various sowing dates and densities, and to optimize the sowing date and density for agricultural high-efficient production in the Jianghuai Plain. Two years of experiments were carried out in the rapeseed growing season in 2020 and 2021. The model parameters were fully calibrated and the simulation performances in different treatments of sowing dates and densities were evaluated. The results indicated that the capability of the AquaCrop model to interpret crop development for different sowing dates was superior to that of sowing densities. For rapeseed canopy development, the RMSE for three sowing dates and densities scenarios were 7–22% and 16–23%, respectively. The simulated biomass and grain yield for different sowing dates treatments (RMSE: 0.8–2.1 t·ha⁻¹, Pe: 0–35.3%) were generally better than those of different densities treatments (RMSE: 0.7–3.9 t·ha⁻¹, Pe: 8.2–90%). Compared with other sowing densities, higher overestimation errors of the biomass and yield were observed for the low-density treatment. Adequate agreement for crop evapotranspiration simulation was achieved, with an R² of 0.79 and RMSE of 26 mm. Combining the simulation results and field data, the optimal sowing scheme for achieving a steadily high yield in the Jianghuai Plain of east China was determined to be sowing in October and a sowing density of 25.0–37.5 plant·m⁻². The study demonstrates the great potential of the AquaCrop model to optimize rapeseed sowing patterns and provides a technical means guidance for the formulation of local winter rapeseed production. Full article

According to previous studies, the Lixiahe area in the east of the Jianghuai River was an alternate environment of land and sea in the middle Holocene, and it was not until the late Holocene that the eastern Jianghuai completely became a terrestrial environment. However, recent archaeological studies have found that the extensive Neolithic sites in the Lixiahe area have recorded the rich human activities and cultural connotations of the prehistoric civilization in the Middle Holocene. In this paper, the Gangxi section of Jianhu Lake, Jiangsu Province (GX2) was selected and pollen analysis was fulfilled, then the geomorphic evolution process of the study area from sea to land was investigated according to the palynological assemblages and algae fossils of brackish water, semi-saline water, fresh water and terrestrial in the section strata. During the period of 8500–3800 cal. BP, GX2 was affected by multiple factors such as sea surface fluctuation, ocean flow and sediment deposition carried by seagoing rivers. Since 5800 cal. BP, the area east of the Grand Canal between the Yangtze River and the Huaihe River, and the west of the Yangzhai town, Funing–Longgang town, Yancheng–Dagang town and Yancheng–west of the Dongtai–Hai’an line, have become a terrestrial environment. After the eastern Jianghuai became a land, the Liangzhu culture (5300–4300 cal. BP) in the Taihu Lake basin in the south wing of the Yangtze River delta expanded to the eastern Jianghuai area, and the Longshan culture and Yueshi culture in the Haidai area in the north also migrated south to the eastern Jianghuai area. Admittedly, the main reason in the process of Neolithic cultural development is the internal motivation that the ancient ancestors struggled with nature and pushed forward the continuous development of civilizations. However, our study explains the palaeogeographical origin of Neolithic culture in the eastern and coastal areas of Jianghuai in the middle Holocene, and meanwhile, provides an example for the man–land relationship research on Neolithic culture. Full article