Abstract:In 2020, the farmland soils of tobacco-rice rotation(TRT) and tobacco-maize rotation(TMT) were collected in Huayuan, Yongshun and Longshan of Xiangxi Prefecture for 5 consecutive years of planting, and the tobacco continuous cropping(TT) was used as the control. The stability of aggregates with particle sizes of r<0.25 mm, 0.25 mm≤r<0.50 mm,0.50