Abstract: Sandy soil leaks water and fertilizers,the structure is loose,and the soil and water loss is serious.The effective improvement of the weathered material of the soft rock can improve the soil structure, quality and promote the utilization efficiency of resources.In order to screen out the compounding ratio with better improvement effect on sandy land,four kinds of compound soils with mixed soft rock to sand ratios of 0∶1 (CK),1∶5 (C1),1∶2 (C2) and 1∶1 (C3) were selected as research objects.The soil organic carbon content, active organic carbon content, bulk density, organic carbon storage and carbon pool management index of 0—30 cm soil layer (10 cm interval)were measured and evaluated.The results showed that,soil organic carbon content showed significant differences only in the 10—20 cm soil layer.Compared with CK, the organic carbon content of the soft rock treatment was significantly reduced by 30.00%—46.36%,and there was no significant difference among the C1,C2 and C3 treatments.In each soil layer,the compounding ratio had a significant effect on the content of soil active organic carbon.Among them,the C2 and C3 treatments significantly increased the content of active organic carbon by 325.00%—491.67% (0—10 cm), 775.00%—787.50% (10—20 cm) and 490.91%—509.09% (20—30 cm).The soil bulk density in each soil layer increased with the increase of the ratio of soft rock.The average bulk density of 0—10 cm soil layer was 1. 77 g/cm³ ,and compared with 0—10 cm soil layer,the bulk density of 10—20 cm and 20—30 cm soil layers increased by 12.43% and 23.16%,respectively.There was no significant difference in soil organic carbon storage in each soil layer.The organic carbon storage in C1 treatment was 13.89% lower than that of CK,and the organic carbon storage in C2 and C3 treatments increased by 4.40% and 3.22% compared to CK in 0—30 cm soil layer.The change of carbon pool management index was consistent with the rule of active organic carbon content,increasing in the 10—20 cm and 20—30 cm soil layers with the increase of soft rock,and in the 0—10 cm soil layer, C2 had the largest carbon pool management index.Therefore,in the process of using soft rock to improve sandy soil,the improvement effect of sandy soil is better when the ratio of soft
rock to sand is 1∶2 to 1∶1.

Key words: Organic carbon storage, Carbon pool management index, Active organic carbon, Soil layer, Sandy soil, Soft rock

摘要： 沙土漏水漏肥、结构松散且水土流失严重，采用砒砂岩风化物对其进行有效改良可以改善土壤结构、提升土壤质量、促进资源利用。为了筛选出对沙土改良效果较好的复配比，选取砒砂岩与沙复配比分别为0∶1（CK）、1∶5（C1）、1∶2（C2）和1∶1（C3）的4种复配土体为研究对象，对复配土0~30 cm土层（间隔10 cm）的土壤有机碳含量、活性有机碳含量、容重、有机碳储量和碳库管理指数进行测定和评估。结果表明，土壤有机碳含量仅在10~20 cm土层表现出显著差异，与CK相比，添加砒砂岩处理的有机碳含量显著降低了30.00%~46.36%，且C1、C2和C3处理间无显著差异。各土层中，复配比对土壤活性有机碳含量有显著的影响，其中C2、C3处理较CK使活性有机碳含量显著增加了325.00%~491.67%(0~10 cm)、775.00%~787.50%(10~20 cm)和490.91%~509.09%(20~30 cm)。各土层中土壤容重随着砒砂岩比例的增加而增加，0~10 cm土层的平均容重为1.77 g/cm³，10~20 cm和20~30 cm土层的平均容重较0~10 cm土层分别增加了12.43%和23.16%。各土层中的有机碳储量无显著差异，在0~30 cm土层中，C1处理的有机碳储量较CK降低了13.89%，C2和C3处理的有机碳储量较CK分别增加了4.40%和3.22%。碳库管理指数与活性有机碳含量的变化规律一致，10~20 cm和20~30 cm土层中均随着砒砂岩比例的增加而增加，而0~10 cm土层中以C2处理的碳库管理指数最大。因此，在利用砒砂岩改良沙土的过程中，当砒砂岩与沙的复配比介于1∶2~1∶1时对沙土的改良效果较好。

关键词: 有机碳储量, 碳库管理指数, 活性有机碳, 土层, 沙土, 砒砂岩