ENVIRONMENTAL TECHNOLOGY & INNOVATION, cilt.23, ss.1-12, 2021 (SCI-Expanded)
In the last two decades, biomass incineration
plants have been widely used to manage bio-waste, crop and forest residues that
produce recalcitrant nutrient-rich biomass ash (BA), but have limited their use
for agricultural purposes. Considering the urgent
needs for a sustainable agro-industrial waste management, the present study
aimed to fulfill the scarcity of the literature in this field by focusing on
one of the bioremediation strategies (vermicomposting) to solubilize the
potential plant nutrients, specifically phosphorus of the BA for crop
fertilization. BA was collected from
the biomass power plant incinerating poultry litter, forest and crop harvest
residues, and then thoroughly incorporated into dewatered dairy manure to
obtain final NPK content of 0.0 (T0), 3.5 (T1), 7.0 (T2),
and 10.0% (T3) on a dry weight basis. Initially, the mixtures were
pre-composted aerobically for 3 weeks to remove toxic gases and then subjected
to vermicomposting for 60 days. The sequential extraction results indicated
that vermicomposting significantly improved solubility of total phosphorus (TP)
and Olsen-P by 69–79% and 5–8%, respectively, depending on the BA doses. Pot experiments were conducted using common bean (Phaseolus vulgaris L.) in 0.0%, 3.5% BA,
7.0% BA and 10.0% BA vermicompost, respectively. The results indicated that BA
vermicompost amendments could promote the growth of bean plants, increase the
content of chlorophyll contents in the leaves, and significantly enhance the
synthesis of leghemoglobin in nitrogen-fixing compartment of root nodules (p < 0.05), which helps the activation
of the biological nitrogen fixation. Findings of this study clearly
demonstrated that vermicomposting of BA with bio-waste could ameliorate the solubility
of nutrients from BA, and nutrient-enriched vermicompost could improve the
nodulation and nitrogen-fixing ability of legume crops, thereby enhancing its recycling
capacity for closing nutrient loop.