The ANOVA results of statistical items in this study.

TOC and δ13C used 96 samples in total; fM, fS, rSM, rM, rS, rS′ and ΔCS used 48 samples in total. T, time; S, soil type; F, Fertility level; M, maize amendment. TOC, total organic carbon; fM, the proportion of maize-derived carbon; fS, the proportion of soil-derived organic carbon; rSM, remaining rate of total organic carbon; rM, remaining rate of maize-derived carbon in the treatment with maize straw; rS, remaining rate of soil-derived organic carbon in the treatment with maize straw; rS′, remaining rate of soil-derived organic carbon in the treatment without maize straw; ΔCS, difference in soil-derived organic carbon between the treatment with and without maize straw. *, **, ***, NS and-, indicate significant differences at P.05, P.01, P.001, no significance and no ANOVA analysis, respectively. df indicates degrees of freedom.The ANOVA results of statistical items in this study.