Temperature and moisture responses to carbon mineralization in the biochar-amended saline soil

摘要

This study assessed the effects of temperature and moisture on carbon mineralization (C_(min)) in a saline soil system with biochar amendment The dynamics of C_(min) were monitored in a biochar-amended saline soil for 220 days by incubation experiments under different conditions of temperature (15 ℃ 25 ℃ and 35 ℃) and moisture (30%, 70% and 105% of the water-holding capacity). Results showed that as the incubation temperature rose, cumulative C_(min) consistently increased in soil added with 0-4% biochar. The two-compartment model could well describe the dynamics of C_(min).The temperature rise increased the concentration of labile C in soil, but reduced the turnover time of labile and recalcitrant C pools and the value of temperature coefficient Q_(10). The response of C_(min) to moisture was varying in soil amended with different levels of biochar. In the control treatment (soil alone), cumulative C_(min) increased only when soil moisture was ＞ 105%. In the biochar treatments, however, 70% of water-holding capacity was optimal for C_(min). except for 2%-biochar treatment at 35 ℃. The findings highlight the necessity to consider the combined effects of soil moisture, temperature and the amount of biochar added for assessing C_(min) in biochar-amended saline soils.