污泥堆肥施用对土壤单位有机碳矿化及 温度敏感性的影响.

[Objective] The main controlling factors of soil organic carbon mineralization and its temperature sensitivity(Q10) for municipal sludge resource utilization and soil carbon pool stability after sludge compost application were revealed, which provided theoretical support for municipal sludge treatment and soil organic carbon sequestration. [Methods] In the present study, different doses of composted sludge (0, 2.0%, 5.0%, 10.0%, 15.0%, and 20.0%) were added to the degraded grassland soil collected from the loess hilly area, and the soil organic carbon mineralization rates under different incubation temperatures (15℃, 25℃ and 35℃) were measured. The effects of composted sludge addition on soil organic carbon mineralization characteristics and Q10 values were discussed. [Results] Compared with CK, the soil organic carbon mineralization rate significantly (p＜0.01) increased with composted sludge addition doses at the initial stage of cultivation, and then it rapidly decreased until it reached to a stable value. The cumulative soil organic carbon mineralization under the composed sludge addition treatments were 1.6～4.2 times greater than that of CK. When the composed sludge application doses were between 10.0% and 20.0%, the organic carbon mineralization rate and cumulative mineralization amount had no significant difference. The first-order kinetic equation was used to fit the dynamics of soil organic carbon mineralization with composted sludge addition treatments at different incubation temperatures and achieved good results (R²＞0.95). Soil organic carbon mineralization potential (C0) values ranged from 6.92 to 39.60 mg C/g and the differences were significant (p＜0.05) among different treatments. The soil organic carbon mineralization kinetic constant (k) ranged from 0.03/d to 0.12/d, and it was significantly correlated with incubation temperatures (p＜0.01). The Q10 values ranged from 1.18 to 2.58 with the composted sludge application doses, and the Q10 reached the maximum value when the application doses reached 10.0%, and then the Q10 values decreased with the doses of the composed sludge addition. [Conclusion] When the composted sludge application doses are at 10.0%～20.0%, the content of soil organic carbon can obviously increase, inhibit the re-mineralization of soil organic carbon, effectively adjust soil Q10, and ensure the relative stability of soil carbon pool, which is beneficial for the sequestration of soil organic carbon. [ABSTRACT FROM AUTHOR]