Abstract:Freeze-thaw has an important effect on wind erosion by changing soil physical properties in the agricultural field of Chinese Mollisol region in late spring. The research analyzed the effects of previous freeze-thaw on wind erosion in agricultural fields based on simulated freeze-thaw and wind tunnel experiments. The experimental treatments included three initial soil moisture contents (16.5%, 24.8% and 33.0%), three wind speeds (9, 12 and 15 m/s), one freeze-thaw cycle, and non previous freeze-thaw experimental treatment was taken as a control. During the experiment, the soil box filled by tested soil samples with different initial moisture contents was firstly placed in the refrigerator to simulate freezing and thawing effect, and then it was air-dried in room temperature until its soil moisture content was approximately 6.0% to 7.0%. Late on, the soil box was placed into the wind tunnel to simulate soil loss by different wind speeds, respectively. The results showed that previous soil freeze-thaw significantly increased wind erosion rate and sediment delivery rate. At the experimental conditions, wind erosion intensity increased by 23.5%~404.2% (P<0.05), and the average sediment delivery rate increased by 59.1%~305.3% (P<0.05), compared with the control treatment; and both increments were related to initial soil moisture content and wind speed. Meanwhile, the wind erosion and sediment delivery rates increased significantly with an increase of wind speed with/without previous soil freeze-thaw action, and the wind erosion intensity followed the power function with increasing of wind velocity. For the previous soil freeze-thaw treatment, the order of increments of wind erosion and sediment delivery rates under three initial soil moisture contents was 16.5% > 33.0% > 24.8%. Moreover, the sediment delivery rate decreased exponentially with an increase of surface height, the wind erosion material was mainly concentrated in the range of 40 cm above the surface; and the previous soil freeze-thaw action increased the sediment delivery height.