an overall trendgold
Our results show an overall trend of cropland expansion from 8 to 2 ka BP, which is consistent with the results of HYDE3.2 ( Figure 5 A). 26 However, our results differ from those of GLUE, 28 which indicated that the area of cropland sharply increased at 7–6 ka BP, while the cropland areas were much lower than those estimated by PLUM and HYDE3.2 in the other periods ( Figure 5 A).