The properties of livestock manure during composting were studied in order
to understand the changes in physical and chemical composition. The compost
ing was carried out in a commercial organic fertilizer plant utilizing aero
bic processes, and the following parameters were measured in samples collec
ted at different stages of composting: moisture content, temperature, total
carbon (C), humic substance (HS) contents and fractions-fulvic acid (PA) a
nd humic acid (HA), and macro- and micronutrients. Correlation analysis was
carried out between these manure properties. Total C and nitrogen (N) decr
eased by 18 and 10% in the final manure at the end of composting. During co
mposting, HA became progressively the dominant fraction of HS. Phosphorus (
P) increased by 31%, potassium (K) by 12%, magnesium (Mg) by 11%, and calci
um (Ca) by 6%, respectively. The C/N ratio decreased slightly from an initi
al value of 14.8 to 12.9 after the composting process. The compost was high
est in iron (Fe) and lowest in copper (Cu) content. Highly significant posi
tive correlations were found between total N and HS, implying that HS could
be the major determinant of N level in the manure. Significant positive co
rrelations were obtained between zinc (Zn) and HS and FA whereas a highly s
ignificant positive correlation was noted for manganese (Mn) and HA. Since
the content of N tended to decline during composting, it could be necessary
to supplement the manure with inorganic sources of N depending on soil nut
rient status and crop requirement.