Abstract:In order to enhance the degree of humification in swine manure compost, this study employed aerobic composting by incorporating vermiculite, zeolite, maifanite, bentonite and magnetite, with each at a dry matter mass fraction of 10%, into the swine manure materials to investigate the effects of various mineral additives on the humification process of swine manure compost. Results indicated that at the end of composting no significant differences in pH were observed among the different treatments. Compared with the control treatment, the mineral additive treatments extended the high-temperature phase of composting and significantly increased the electrical conductivity(EC), total nitrogen(TN) mass fraction, germination index(GI) and humic acid(HA) mass fraction of compost, while the total carbon(TC) mass fraction, C/N ratio(C/N) and fulvic acid(FA) mass fraction of compost were all decreased significantly. The bentonite-treated samples increased the high-temperature phase by 9 days, with significant increasing in EC(14.66%), TN mass fraction(30.50%), GI(22.63%), and HA mass fraction(45.36%) of compost, while with this treatment, TC mass fraction(12.61%), C/N(33.02%), and FA mass fraction(25.63%) of compost decreased significantly. The mineral additive treatments significantly increased the HA/FA ratio of compost by 71.82% to 94.39%, with bentonite treatment showing the best effect. HA/FA showed extremely significant positive correlations with EC, C/N, GI, as well as with the mass fractions of TC, TN, HA and FA. The influence of FA mass fraction, TN mass fraction, HA mass fraction, C/N, TC mass fraction, EC, and GI on the HA/FA decreased in the following order. In summary, the addition of bentonite increased TN mass fraction, GI, HA mass fraction and HA/FA of compost, which in turn increased the degree of compost humification. Therefore, it is recommended to add bentonite to the aerobic composting process of swine manure.