Vermicompost enrichment using organic wastes: Nitrogen content and mineralization

Purpose This study performed a feasibility assessment of nitrogen enrichment by some organic wastes through vermicomposting as well as its release as a bioavailable form over time. Methods Soybean and canola wastes as well as the dairy blood powder of industrial slaughterhouse were used as organic wastes to enrich the vermicompost. Composted materials were incubated for nitrogen mineralization kinetic assessment by adjusting moisture content to ۵۰% at ۳۰ ˚C for ۸۰ days. During the incubation, moisture was maintained by weighing. Subsamples were collected after ۱, ۵, ۱۰, ۲۰, ۴۰, ۶۰, and ۸۰ days of incubation. Results Among the treatments, those for ۲۵% dairy blood powder contained the highest nitrogen content (۴.۹۵ and ۳.۷۰% for chicken and cow blood powder, respectively). Nitrogen mineralization through ۸۰ days of incubation ranged from ۲.۲۳% (for ۵۰% canola waste treatment) to ۲.۵۷% (for ۲۵% blood powder) of the total nitrogen. The mineralization rate ranged from ۴.۲۴ and ۳.۶۲ mg kg-۱ day-۱ for the compost containing ۲۵% chicken and cow blood powder, respectively, to ۰.۹۴ and ۰.۸۴ mg kg-۱ day-۱ in canola and soybean waste, respectively, whereas those for the control treatment equaled ۰.۸۱ mg kg-۱ day-۱. Conclusion Composts containing ۲۵% blood powder were acceptable in terms of quantity and nitrogen release over time, and can serve as a reliable source of available nutrients in the soil.

کلیدواژه ها:

vermicompost ، enrichment ، nitrogen ، Mineralization