Composting poultry manure with rice hulls and/or sawdust in NE Argentina

LECONTE, M.C.; MAZZARINO, M.J.; SATTI, P.; IGLESIAS, M.; LAOS, F.

WASTE MANAGEMENT (ELMSFORD)

Elsevier

Año: 2009

0956-053X

In subtropical NE Argentina considerable amounts of C-rich wastes are generated from rice and timber agro-industries, a common fate being uncontrolled burning. Since both wastes are rich in recalcitrant C and have a high C/N ratio, they need to be composted with a nitrogenous source, such as poultry manure. The effect of different proportions of poultry manure, rice hulls and/or sawdust on composting efficiency and final compost quality was studied. Five piles were prepared with a 2:1 and 1:1 ratio of sawdust (or rice hulls) to poultry manure, and 1:1:1 of all three materials (V/V). Different indicators of compost stability and quality were measured. Thermophilic phase was shorter in piles with rice hulls (60 days vs. 100 days in piles containing sawdust). Time required for stability was similar for both carbonous materials (about 180 days). Final composts showed pH values of 5.8-7.2, electrical conductivity 2.5-3.3 mS/cm, organic C 20-26%, total N 2.2-2.9 %, lignin 19-22%, total Ca 18-24 g/kg and extractable P 6-8 g/kg, the latter representing 60 % of total P. Nitrogen conservation was high in all piles, particularly that with both carbonous materials. Piles containing sawdust were characterized by high total and available N, while piles with only rice hulls had higher Si, K and pH. Extractable P was higher in 1:1 piles, and organic C in 2:1 piles.