Effects of Poultry Manure and Portland Cement Additions on Soil Physical Properties and Microbial Activities

The topsoil sample (0-15 cm) of the Apomu series (Inceptisol) was amended with three rates each of poultry manure and cement (0, 5.0, 10.0 g / kg) in a 3 x 3 factorial combination. The experiment was carried out in the laboratory at room temperature. The poultry manure and cement were thoroughly mixed by hand with 100 g portions of air-dried, sieved (2 mm) soil samples and allowed to incubate for 4 and 8 weeks for total heterotrophic microbial counts, and CO2 evolution, respectively. Bulk density and water-holding capacity were also determined at the end of 16 weeks of incubation. Poultry manure additions significantly (p< 0.05) increased bacterial and fungal numbers over the control while cement addition significantly (p< 0.05) increased bacterial numbers only. The interaction effect was significant (p < 0.05). While the fungal population was significantly (p < 0.05) decreased at the highest rate of cement addition, the counts were significantly (p < 0.05) increased over the control by the poultry manure additions. The poultry manure, cement and their mixtures significantly (p < 0.05) increased CO2 evolution over the control. While there was no significant (p < 0.05) difference with the cement additions, CO2 evolution was significantly (p <0.05) increased with an increase in the rate of poultry manure addition. The interaction effects of poultry manure and cement were not significant on water-holding capacity but were significant (p < 0.05) at the highest level of poultry manure on bulk density. However, while bulk density was reduced by poultry manure over the control, cement had no significant (p < 0.05) effect on it. The water-holding capacity was significantly (p <0.05) increased by poultry manure. While the 5.0 g / kg cement addition increased water-holding capacity over the control, there was no significant difference at the highest level of addition.