Abstract:

In order to explore the effects of different nitrogen sources and carbon nitrogen ratios on aerobic composting of Euryale shells, and provide a new approach for the resource utilization of Euryale shells,the experiment used crushed Euryale shells as composting material, organic nitrogen source rapeseed meal and inorganic nitrogen source urea as added nitrogen sources in the compost, and set the initial carbon nitrogen ratio (C/N) of compost to 25 and 30, respectively. A small-scale indoor composting experiment was conducted to study the dynamic changes of temperature, pH value, electric conductivity (EC), carbon and nitrogen nutrients, as well as the differences in humification rate and germination index after composting. The results showed that composting treatment using rapeseed meal as a nitrogen source was easier to reach higher fermentation temperatures than urea, and only T1 treatment with a C/N of 25 could reach temperatures above 50 ℃. After composting, the EC value, ammonium nitrogen, total nitrogen, and extractable humic acid content of the compost treatment with rapeseed meal as the nitrogen source and C/N of 25 were higher than those of the other treatments, and the humification rate reached 14.23%, significantly higher than the other three treatments. Taking all factors into consideration, under the conditions of this experiment, using organic nitrogen source rapeseed meal as the nitrogen source and with an initial fermentation C/N of 25, a relatively good aerobic fermentation effect can be achieved, which can provide some theoretical and technical guidance for the harmless treatment of Euryale shells waste.

Key words: Euryale shells, aerobic composting, nitrogen source, carbon nitrogen ratio