This research evaluates how organic amendments, particularly water hyacinth compost (WHC) and chicken manure (CM), can rehabilitate the degraded sandy loam soil at the J.K. College Premises (CP), Purulia, West Bengal, India. Soil quality and plant growth had been severely impacted due to construction activities. Spinach was used as an indicator crop because of its rapid foliar growth, making it a sensitive marker for amendments’ effects. Treatment with WHC and CM significantly improved several growth parameters, including root length, root diameter, shoot height, and leaf area. The application of WHC and CM (organic compost and manure, referred to as OCM or amended soil) increased soil fertility, evidenced by reductions in bulk density from 1.194 g/cm³ to 0.825 g/cm³ and an increase in porosity from 45.28% to 68.87%. Total nitrogen rose from 357.8 to 1120 mg/kg, with notable gains in phosphorus and potassium as well. Statistical analysis using Two-Way ANOVA confirmed significant treatment effects. Results were visualized through matrix-based heatmaps in R 4.3.2, showing clear biometric trends. Microbial diversity, assessed via 16S rRNA and ITS amplicon sequencing, was markedly higher in OCM (2,962 bacterial and 937 fungal species) compared to CP (427 and 899 species, respectively). This elevated diversity in OCM soil reflects the effect of nutrient-rich inputs like WHC and CM, which support beneficial taxa such as Actinomadura keratinolytica. In contrast, the lower diversity in CP soil suggests nutrient limitations that may weaken ecological resilience and hinder crop productivity, with dominated by Bacillus mannanilyticus. Fungal community shifts were less pronounced. Visualization tools, including stacked bar charts at various taxonomic levels and Sankey diagrams for dominant taxa, effectively illustrated microbial community changes. Overall, this study shows that WHC and CM amendments significantly restore soil health, boost microbial diversity, and improve crop productivity in degraded semi-urban soils.
Parveen et al. (Wed,) studied this question.