ABSTRACT
The objective of this research was to study the change of the carbon and nitrogen concentration and the relationship C/N of the stacks in the composting of the sugar cane trash (with or without addition of gypsum and of triple phosphate), of the grinded napier grass and coffee straw, when liquid pig manure was used as a nitrogen source. Exponential curves, obtained by regression analysis, were adjusted to the concentration data to obtain the decomposition constants of the organic material and of nitrogen accumulation in the stacks. The constant average of the organic material decomposition was of 0.003673 d-1 and the average rate of nitrogen accumulation of 0.006014 d-1, having processing period being between 90 and 133 days.
Key words:
composting; organic residues; liquid pig manure