Abstract:

Two different types of sand accretion instruments were installed on the abandoned farmland of different years, and the similarities and differences of the two sand accretion instruments were analyzed through a comparative study on the structural characteristics of the wind sand flow, so as to select the ideal sand accretion instruments for the study of wind sand flow under different wind sand environment conditions in arid and desert areas. The results showed that (1) the annual sediment transport of No.2 sand accretion instrument was significantly higher than that of No.1, the higher the wind sand flow, the greater the difference, and the difference had a close relationship with the distance to sand source, the farther distance, the more obvious the difference; (2) there was a significant linear correlation between the annual sediment transport volume of the two sand accretion instruments, and the correlation coefficient was up to 0.998, indicating that there was a significant linear correlation between the amount of wind sand flow collected by the two sand accretion instruments; (3) according to the monthly variation of sediment transport rate of the two kinds of sand accretion instruments, the overall performance was that the sediment transport amount was consistent with the local wind season, and the monthly variation rules between them were also very similar, however, the sediment transport amount of each month still showed that the sand accretion instrument 2 was greater than that of the sand accretion instrument 1; (4) under the same wind speed, the sediment transport rate of the two kinds of sand accretion instruments showed a downward trend with the increase of the number of years of farmland returning, the longer the number of years of farmland returning, the larger the sediment transport rate was, and the larger the change range was within the range of 0-50 cm; while, the shorter the time of farmland returning, the smaller the sediment transport rate was, and the small change range was within the range of 0-50 cm. The results showed that under the same condition, the sand volume collected by sand accretion instruments 2 was 1.7-1.9 times of that collected by sand accretion instrument 1. The two kinds of sand accretion instruments could be used to observe sand flow in areas with large amount of wind-sand, while good results could be obtained when sand accretion instrument 2 was used to observe sand flow in areas with small amount of wind sand.

Key words: abandoned farmland, sand accretion instrument, wind sand flow, sediment transport, sediment transport rate