Role of selenite on the nitrogen conservation and greenhouse gases mitigation during the goat manure composting process

• Published in: The Science of the total environment 2022-09, Vol.838 (Pt 1), p.155799-155799, Article 155799
• Main Authors: Ren, Xiuna, Wang, Zhaoyu, Zhao, Mengxiang, Xie, Jianwen, Zhang, Zengqiang, Yang, Fengxia, Wang, Quan, Ding, Yongzhen
• Format: Article
• Language: English
• Subjects: Composting; Goat manure; Greenhouse gases emission; Nitrogen conservation; Selenite
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2022.155799

This study aimed to explore the roles of selenite (Se) on nitrogen conservation and greenhouse gases (GHGs) mitigation during the composting process. Six levels of Se(IV) dosages (i.e. 0, 2, 4, 6, 8 and 10 mg/kg) were examined for 80-day composting of goat manure and wheat straw mixtures, where the different blending proportions were marked as T1 (Control), T2, T3, T4, T5 and T6, respectively. The results showed that adding Se(IV) was beneficial for reducing NH3 by 3.50–42.41% by buffering pH and promoting nitrification. For N2O, it showed different responses to different Se(IV) dosages, and it was increased by 29.62–71.29% in T2-T4 but reduced by 30.45–69.54% in T5-T6. Methane (CH4), another main component of GHGs, was increased by 1.35–107.42% by adding 2–10 mg/kg Se(IV). To further evaluate the effect of Se(IV) on GHGs, global warming potential value was calculated, which was 103.32–499.80 and minimum value was in T5. Furthermore, the physicochemical indexes, especially temperature and OM, had vital effects on microbial community. Overall, the results obtained from this study demonstrated that the application of Se (IV) in composting was reasonable to generate Se-rich organic fertilizer, and the 8 mg/kg was suggested from perspectives of nitrogen conservation and GHGs reduction. [Display omitted] •Adding Se(IV) into composting had no inhibiting effect on maturity of products.•The addition of Se(IV) led to NH3 reduction and CH4 increasement.•Adding 2–6 mg/kg Se(IV) increased N2O emission while 8–10 mg/kg Se(IV) reduced N2O.•The treatment blended with 8 mg/kg Se(IV) had lowest global warming potential.