Five coal samples obtained from Chinese coal-producing areas were oxidized by hydrogen peroxide (H2O2), and humic acids (HAs) were derived from original coal and its oxidizition samples. HAs were characterized by physical and chemical methods, between which was also comparison. Yield, ash, aromaticity, molecular weight and functional group of HAs showed variance between original coals. While, yield, molecular weight, and the quantity of oxygen-containing groups of HAs increased more from coals oxidized with H2O2. However, the increase of oxygen-containing functional groups depended on original coals. For Yimin lignite, the oxidation of H2O2 could obviously improve the carboxyl group content of HAs, thus promoting the adsorption of nitrogen. This study demonstrated that oxidation of coal by using H2O2 was one pretreatment way to obtain and modify HAs which could be used as prerequisite and functional material in agricultural field.

Synthetic fungicides are eco-unfriendly to agriculture and the environment. Agricultural Jiaosu (AJ), which originates from organic wastes, has the potential to be a substitute for synthetic fungicides. In this study, the characteristics of AJ and its antifungal activity against Botrytis cinerea were investigated for the first time. AJ was rich in lactic acid (4.46 g/L), acetic acid (1.52 g/L), Lactobacillus (72.45 %) and Acetobacter (15.23%), which was a microbial ecosystem consisting of acid-based substances (AS) and beneficial microorganisms (BM). The results of the antifungal assays suggested that B. cinerea was effectively inhibited by AJ, with the half-maximal inhibitory concentration (IC50) of 9.24%. AJ showed the strongest and most-lasting inhibitory effect compared to cell-free supernatant and microbial solution of AJ, indicating that AS and BM and their synergistic effect contributed to the antifungal activity of AJ. Two-step inhibition’ is an antifungal mode of AJ. Firstly, AS not only inhibited the pathogen directly but also provided a dominant niche for BM of AJ. Then, BM in AJ, especially Acetobacter, proliferated and metabolized acetic acid continuously. Thus, AJ achieved high-efficiency and long-acting inhibition. AJ is a promising biological agent considering its features of an eco-friendly, low-cost and easy-to-operate biological agent in rural areas

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Synthetic fungicides are eco-unfriendly to agriculture and the environment. Agricultural Jiaosu (AJ), which originates from organic wastes, has the potential to be a substitute for synthetic fungicides. In this study, the characteristics of AJ and its antifungal activity against Botrytis cinerea were investigated for the first time. AJ was rich in lactic acid (4.46 g/L), acetic acid (1.52 g/L), Lactobacillus (72.45%) and Acetobacter (15.23%), which was a microbial ecosystem consisting of acid-based substances (AS) and beneficial microorganisms (BM). The results of the antifungal assays suggested that B. cinerea was effectively inhibited by AJ, with the half-maximal inhibitory concentration (IC50) of 9.24%. AJ showed the strongest and most-lasting inhibitory effect compared to cell-free supernatant and microbial solution of AJ, indicating that AS and BM and their synergistic effect contributed to the antifungal activity of AJ. Two-step inhibition’ is an antifungal mode of AJ. Firstly, AS not only inhibited the pathogen directly but also provided a dominant niche for BM of AJ. Then, BM in AJ, especially Acetobacter, proliferated and metabolized acetic acid continuously. Thus, AJ achieved high-efficiency and long-acting inhibition. AJ is a promising biological agent considering its features of an eco-friendly, low-cost and easy-to-operate biological agent in rural areas.

No abstract