Both raw and composted poultry manure is applied as soil amendment. The aims of this study were: (1) to develop phytotoxicity indexes for organic wastes and composts, and (2) to assess the correlation among phytotoxicity indexes, ecotoxicological endpoints and stability and physicochemical parameters during passive composting of poultry manure. Six 2-m(3) composting piles were constructed and four parameter groups (physicochemical and microbiological parameters, ecotoxicological endpoints, and biological activity) were determined at four sampling times during 92days. Extracts were used to carry out acute toxicity tests on Daphnia magna, Lactuca sativa and Raphanus sativus. Composting decreased average toxicity 22.8% for the 3 species and D. magna was the most sensitive species. The static respiration index decreased from 1.12 to 0.46mgO2gOMh(-1) whilst organic matter reduced by 64.1% at the end of the process. Escherichia coli colonies remained higher than values recommended by international guidelines. The D. magna immobilization test allowed the assessment of possible leachate or run-off toxicity. The new phytotoxicity indexes (RGIC0.8 and GIC80%), proposed in this study, as well as salinity, proved to be good maturity indicators. Hence, these phytotoxicity indexes could be implemented in monitoring strategies as useful ecotoxicological tools. Multivariate analyses demonstrated positive correlations between ecotoxicological endpoints (low toxicity) and biological activity (stability). These two parameter groups were associated at the final sampling time and showed negative correlations with several physicochemical parameters (organic and inorganic contents). The final poultry manure compost was rendered stable, but immature and, thus, unsuitable for soil amending.

The aim of this work was to evaluate the composting process of poultry manure mixed with other complementary organic wastes. Two mixtures (treatment 1 and 2) were prepared with corn bare cobs, sawdust, shavings and manure. Temperature, pH, electrical conductivity, organic matter loss, total organic carbon, solved organic carbon, N loss, ammonium and nitrate concentration, laccase activity and respiration indices were analyzed. These variables showed similar tendencies during the composting process in both treatments. A peak of biological activity, organic matter mineralization and salt release was observed after 6 days of the process. Treatment 2 showed a higher concentration of solved organic carbon and higher organic matter loss than in the mixture with less manure (treatment 1). Laccase activity increased when solved organic carbon decreased. Compost from treatment 1 showed lower phytotoxic effects than that from treatment 2, probably because of a low salt content. In conclusion, it was observed that 60 % content of poultry manure in the mixture does not affect the composting process. However, the final product is not as good for agricultural purposes as a mixture with a lower manure content. Finally, it can be stated that the valorization of these wastes in the form of compost adds value to the materials, closing the biogeochemical nutrient cycle.

Actualmente el uso de sustrato se ha incrementado en varios sectores agrícolas. Entre los materiales empleados para su formulación se encuentran los compost, y como todo componente es importante conocer sus propiedades previo a su uso. El objetivo de este trabajo fue caracterizar 15 compost de diferentes orígenes, para evaluarlos como componente de sustrato. Se analizaron los siguientes parámetros: densidad aparente, espacio poroso total, capacidad de retención de agua (CRA), porosidad de aireación (PA), granulometría, pH, conductividad eléctrica (CE), concentración de calcio, magnesio, potasio, sodio y nitratos. Hubo diferencias significativas (P < 0,05) entre los compost para todas las variables analizadas. La densidad aparente fue mayor en el compost de ave de corral. El compost de corteza de pino gruesa tuvo el mayor porcentaje de PA y el compost de residuos de poda el mayor porcentaje de CRA. Los compost de corteza de pino podrían ser componentes que aportarían aireación en una formulación de sustrato. Los valores de pH obtenidos se encontraron entre 4,7 a 8,7 y de CE entre 0,09 a 5,55 dS m^-1. La mayoría de los compost superaron el rango adecuado de pH (5,5-6,3) y si bien la mayoría no tuvieron una CE elevada, hubo algunos como el compost de ave de corral, de residuos sólidos urbanos y de residuos porcinos que superaron 1 dS m^-1, y podrían causar efectos nocivos en las plantas. Todos los compost son viables para su uso teniendo en cuenta sus propiedades y las condiciones del cultivo en que se va a utilizar el sustrato formulado.