EFFECT OF SOIL LAYER THICKNESS ON ORGANIC CARBON MINERALIZATION IN IMPROVED SANDY LAND

Soft rock and sand are interspersed in the Mu Us Sandy Land, and the land degradation is severe. Using soft rock and sand as resources on the spot is of great significance to promote the environmental construction and human settlement structure of the area. In this paper, the soft rock and sand are mixed according to the volume ratio of 0:1 (CK), 1:5 (51), 1:2 (S2) and 1:1 (S3) to construct a soil plow layer. And based on the 0 similar to 30 cm soil layer, the mineralization of soil organic carbon was studied. The results show that as the proportion of soft rock increases, the organic carbon content of the 10-20 cm soil layer gradually decreases. With the increase of the soil layer, the soil organic carbon mineralization rate and cumulative mineralization amount are the highest in the 10 similar to 20 cm soil layer, followed by 0 similar to 10 cm and 20 similar to 30 cm. With the extension of the cultivation time, the mineralization intensity showed a trend of first decreasing, then increasing and finally decreasing steadily. At the end of the cultivation, the organic carbon mineralization rate of the compound soil was between 3.10 similar to 10.47mg/(kg.d(-1)). The cumulative mineralization rate of soil organic carbon in each soil layer has different performances. The average value is the lowest at 0 similar to 10 cm, which is 20.54%, and its value increases with the increase of arsenic content. The change trend of the potential mineralizable organic carbon content is consistent with the cumulative mineralization amount. The mineralization amount treated with S1 and S2 is relatively small, and the half-turnover period is opposite to the change trend of the mineralization rate constant. The difference was significant only in the 0 similar to 10 cm soil layer in the half turnover period, and the treatment of adding arsenic sandstone was significantly higher than that of CK treatment. In conclusion, the organic carbon in the 0 similar to 10 cm soil layer is relatively stable and still in the process of soil formation and development, and the carbon sequestration ability is stronger when the ratio of arsenic sandstone to sand reclamation is between 1:5 and 1:2.