Study on the Process of Water-soluble Organic Carbon Fertilizer Prepared from the Fermentation Products of the Mixture of Rice Straw and Peanut Bran

Objective The suitable C/N ratio and extraction time for producing water-soluble organic carbon fertilizer from discarded rice straw and peanut bran fermented by different commercial microbial fermentation agents were studied, and the suitable fermentation agent was selected.

Method Rice straw and peanut bran were used as mixed raw materials, and the C/N ratio was 25∶1 and 40∶1. Six kinds of commercial microbial fermentation agents were used for solid-state fermentation and the organic carbon contents in the fermentation products were determined. Then, the water soluble organic fertilizer was prepared by leaching, the extraction efficiency and extraction amount water-soluble carbon were determined, and the suitable C/N ratio, fermentation agent and extraction time were identified by multivariate analysis of variance.

Result The organic carbon content, water-soluble organic carbon extraction rate and amount of fermentation product with 25∶1 C/N ratio were higher than those with 40∶1 C/N ratio. The organic carbon content in the mixed fermentation product of"fertilizer microorganism"from Hubei and the"manure-fertilizer-grass-feed multiple cycle cascade utilization comprehensive supporting starter"from Hunan with 25∶1 C/N ratio was the highest. However, after leaching for 12 hours, water-soluble organic carbon extraction rate and amount of the mixed fermentation product of"compost fermentation bacteria organic fermentation agent"with 25∶1 C/N ratio from Guangzhou was the highest, followed by that of"fertilizer microorganism"from Hubei after leaching for 24 hours. For the mixture of rice straw and peanut bran with 25∶1 C/N ratio fermented by "compost fermentation bacteria organic material starter", the organic carbon content in fermentation product was 177.56 g/kg, and water-soluble organic carbon extraction amount and rate were 18.22 g/kg and 10.26% respectively after extracting for 12 hours.

Conclusion For the preparation of water- soluble organic carbon fertilizer from the mixture of rice straw and peanut bran by fermentation with starter, the optimal C/N ratio of the mixture of rice straw and peanut bran was 25∶1, the optimal fermentation agent was"compost fermentation bacteria organic material starter"from Guangzhou, and the optimal extraction time was 12 h.