Abstract
The behavior of different organic manures may vary in soil because of their compositional differences. The basic objective of
this study was to examine the fundamental characteristics of the traditional organic manures and their direct effect upon
aggregate formation and stability. The organic manures i.e. municipal solid waste compost, farmyard manure and poultry litter
were characterized on the basis of total organic carbon, total polysaccharides, microbial biomass carbon, humic and fulvic acid
content. A two years field trial was executed by applying each of these manures at four levels i.e. 0, 0.25, 0.50 and 1% of soil
organic carbon in a randomized complete block design. Poultry litter dominated in the carbonaceous compounds in its
composition and under field conditions its application at 0.25% level significantly enhanced the macro aggregate formation
(2-4 and 1-2 mm) which reflected in mean weight diameter (MWD) as 1.48 mm and effective sizes at D10, D30 and D60
(0.0261, 0.099 and 0.732 mm, respectively). The application of MSW compost at 0.25% level significantly improved the MWD
of wet aggregates (5.5 mm) and carbon concentration of macro aggregates (2-4, 1-2 and 0.5-1 mm)
