The different addition proportions of foreign soil has an important impact on the improvement effect and economic cost of iron ore waste reclamation soil. From January to December in 2019

field experiments and laboratory analysis were conducted to investigate the dynamic characteristics of soil carbon emission and reveal its driving factors. In the natural remediation state

the volume ratios of iron ore waste to foreign soil were set as T1 (1:1)

T2 (1:2)

T3 (1:4) and T4 (0:1)

respectively. The physical and chemical properties of the mixed soil were determined in April

July

October and December 2019. The results showed that the carbon emission of mixed soil of iron ore and waste rock was higher in summer and lower in winter with the rise and fall of temperature. With the increase of the proportions of foreign soil

the carbon emission of mixed soil had an increasing trend

and the difference was significant only from July to September

which was T4 (0:1) > T2 (1:2) > T3 (1:4) > T1 (1:1). On the daily scale

the maximum carbon emission appeared at 12:00-14:00 pm

and the minimum appeared at 4:00-6:00 am. When the temperature of mixed soil was low

the carbon emission appeared negative. With the increase of the proportions of foreign soil

the sensitivity coefficient Q10 of carbon emission of iron ore waste rock mixed soil gradually increased (2.07~2.37)

and the addition of foreign soil reduced the pH values of mixed soil to a certain extent

but increased the contents of available phosphorus

total nitrogen

organic carbon and the activities of catalase and sucrase. Comprehensive study on the effects of physical and chemical properties of mixed soil of iron ore and waste rock on carbon emission can provide a theoretical basis for the study of soil carbon emission in iron ore reclamation area.