Degradations of tannin and saponin during co-composting of shell and seed cake of Camellia oleifera Abel

The degradation processes were studied in this paper of tannin and saponin during the co-composting of the shell and seed cake of Camellia oleifera Abel. Four treatments were designed with the dry weight of the seed cake accounting for 1/3(A1), 1/4(A2), 1/5(A3), and 1/10(A4) of the shell. The proportion of the seed cake is positively correlated with the duration of thermophilic phase, highest temperature and degradation rate of tannin and saponin whose maximum were in A1, but negatively correlated with C/N ratio and tannin content which were least in A1 of the final products. The content of saponin were all about 2% finally. The final content of saponin and tannin decreased 68.92-75.22% and 34.57-59.52%. The organic matters, total nutrient (N, P2O5 and K2O) increased with the rising proportion of the seed cake. Overall, the addition of the seed cake promoted the stability, fertilizer efficiency and safety of the co-compost product.