Abstract:
Disposal and proper management of garden waste in urban and semi-urban areas of Sri Lanka have become a
problem due to several constraints. Compost production by introducing common additives to garden waste will be
an effective solution to overcome this problem. It ensures good quality compost and nutrient supply for the
growth of the plants in home gardening. Therefore, the objective of the present study was to determine the effects
of different additives on the quality of composts produced from garden leaf litter. By applying a mixing formula,
five additives were mixed separately keeping a constant weight of dry leaf litter and the C:N ratio as 25:1 in the
compost piles except for the control treatment; (i) dry leaf litter + Gliricidia leaves (Gliricidia sepium)-GLL, (ii)
dry leaf litter + Siam weed (Chromolaena odorata)-SWL, (iii) dry leaf litter + cattle manure-CML, (iv) dry leaf
litter + spent poultry layer litter/poultry manure-PLL, and (v) dry leaf litter + urea-UL. As the control treatment,
a compost pile was prepared only with leaf litter (LL). After 90 days of composting, the chemical properties of
different composts were determined and compared. The characterization included pH, EC, NH4
+
-N, NO3
-
-N,
available P and available K using standard analytical methods. The pH, EC and C/N ratio values were compared
with the indices given by Sri Lanka Standard Institute (SLSI). According to the results, pH and EC were within
the standard levels. The different additives have caused differences in NH4
+
-N and NO3
-
-N in final compost
mixtures. However, the P and K availability has not shown any significant effect with selected additives in leaf
litter composting. The C/N ratio of GLL, CML, SWL and LL composts were between 10 and 20, achieving the
SLSI standards. In this study, considering the compost characteristics, it could conclude that the additives such as
Gliricidia, Siam weed, cattle manure, which have considered in this study could be used with ordinary leaf litter
for composting. The ordinary garden leaf litter without any additives has also complied with the compost
standards.
