Responses of feldspathic sandstone and sand-reconstituted soil C and N to freeze–thaw cycles

Abstract

Abstract The Mu Us Desert in China is significantly affected by seasonal freeze–thaw processes. In order to evaluate the adaptation potential of reconstituted soil with different proportions of feldspathic sandstone and sand to extreme environment, the laboratory simulation freeze-thaw experiments was conducted to study the characteristics of soil C and N under freeze–thaw conditions. The results showed that the content of soil organic matter reached the peak after two cycles of freezing and thawing in T1, T2 and T3, compared to before freeze–thaw cycle, the soil organic matter content increased by 70, 55 and 59%. After ten cycles of freezing and thawing, the content of soil organic matter increased significantly in T2 and T3. After one cycle of freezing and thawing, soil nitrogen content reached the peak. After ten cycles of freeze–thaw cycle, compared to before freeze–thaw cycle, the contents of ammonium nitrogen increased by 10, 49 and 11%, and the contents of nitrate nitrogen increased by 14, 39 and 34% in T1, T2 and T3. In conclusion, short-term freeze–thaw cycles in the Mu Us Desert significantly increased the accumulation of soil carbon and nitrogen reconstructed by different ratios of feldspathic sandstone and sand, and T2 and T3 treatments had better retention performance on soil organic matter and nitrogen, which has a good adaptability to the extreme environment.