Abstract:
Water hyacinth (WH) (Eichhornia crassipes L.) is an aquatic weed that invades freshwater bodies.
Utilizing WH for composting presents a sustainable management technique for WH. In this study,
WH was employed in various ratios to prepare compost piles with a combination of cattle manure
and Albizia sawdust. The cattle manure and Albizia sawdust were mixed in a 1:1 ratio to create a
base mixture (M), which was then used to prepare compost with WH. The ratios of WH:M in the
compost piles were designated as follows: 1:0 (T0), 1:1 (T1), 2:1 (T2), and 3:1 (T3). The
physicochemical properties of the composite samples from each pile were examined after a 120-
day period. The resulting compost from all mixtures exhibited a brown or black color, a pleasant
odor, a soil-like texture, and a reduction in moisture content, indicating efficient decomposition.
The pH remained within the optimal range (6.5 – 8.5) for all samples. T0, T1, T2, and T3 samples
recorded EC (dS/m) values of 6.01, 2.35, 3.56, and 4.24, respectively. However, T0 and T3 did not
meet the Sri Lanka standards (SLS). Total N of T0 (1.084%+0.001%) and T2 (1.395%+0.021%)
reached the acceptable level according to SLS, with T2 being significantly higher. There were no
significant differences in P and K content among the compost samples. The C:N ratio was within
the recommended range (10-25) for T0, T1, and T2, but T3 recorded a higher value
(35.81%+0.75%) than recommended. Further, Na, Ca, and Mg were observed in smaller quantities
in all samples, and heavy metals (Mn, Fe, Cr, Ni, Cu, Cd, Pb, As, and Zn) were within acceptable
ranges according to SLS. The results indicated that all parameters studied in T2 were within the
appropriate ranges according to SLS. Hence, the 2:1 ratio of WH:cattle manure and Albizia
sawdust is deemed the optimal mixture for compost production using WH. This study
demonstrates that WH can be effectively composted with cattle manure and sawdust.
Additionally, the study emphasizes the potential of WH for sustainable utilization in composting
owing to its prolific growth.
