Data.xlsx

We determined SOC, its fraction content and soil aggregates with three vegetation restoration practices to determine the effects of vegetation restoration on SOC stability and driving mechanisms. The K2CrO7-H2SO4 oxidation and titration using FeSO4 was used for SOC analysis (Bao, 2000). The soil samples were sieved and digested using potassium dichromate and concentrated sulfuric acid. After digestion, carbon content was measured by titration. The acid hydrolysis used for ROC analysis (Rovira et al., 2002). The samples were digestd with hydrochloric acid and washed with distilled water until hydrochloric acid was free. After drying, the carbon content was measured by potassium dichromate oxidation and external heating method. Easily oxidizable carbon (EOC) was extracted with KMnO4 then measured using the method of oxidation (Loginow et al., 1987). Soil samples were oxidized with KMnO4 for 1 h and diluted with distilled water for colorimetry. Carbon content was calculated according to KMnO4 consumption. DOC was extracted from fresh soil with deionized water (Alburquerque et al., 2014). Samples were shaken in high pure water for 1 h, and then filtered by filtration membrane. The carbon content in the filtrate was determined by total organic carbon analyzer (Elementar, Germeany). MBC was extracted using the chloroform (CHCl3) fumigation-incubation method (Qiang et al., 2004). Fresh samples were fumigated with CHCl3 for 24h, and the fresh samples were taken as control. The fumigated and fresh samples were extracted with K2SO4, shaken for 1 h, and calculated from the difference in carbon content and conversion coefficient measured between fumigated and control samples. Soil aggregates was analysed by particle size analysis approach. Following Six et al (2002b), the sieves of a vibrating sieving instrument were placed in a bucket in the order of 0.25 and 0.053 mm from top to bottom. Air-dried soil was then placed on the top sieve layer after removing the plant residues and small stones. Then the laster particle size analyzer (Ke Jing BT-9300ST) was turned on for particle size analysis and aggregates were weighed and recorded. Soil aggregates were divided into macroaggregate (> 0.25 mm), microaggregate (0.25 - 0.053 mm) and unaggregated silt + clay (< 0.053 mm). SOC contents of the aggregate fractions soil were determined using the method of KMnO4 oxidation (Loginow et al., 1987). SOC component allocation ratio can reflect SOC conversion efficiency and indirectly characterize SOC stability. SOC component distribution proportion (ROC/SOC, EOC/SOC, DOC/SOC and MBC/SOC) was calculated as follows (Blair et al., 2000) ： (1) The proportion of aggregates associated SOC in total SOC is also known as the contribution rate of aggregates associated SOC to total SOC. The soil aggregates associated SOC contribution rate was calculated as follows (Li et al., 2014): (2) Where, aggregates associated SOC content of aggregates with different particle sizes.