Changes in Physical and Chemical Properties of Soil in Timber Sawmill Dumpsite in Abakaliki, Abakaliki Southeastern, Nigeria

A study to assess changes in the physical and chemical properties of soil in timber saw mill dumpsite was carried out in Abakaliki between 2007 and 2008. Results showed that soil textural class remained sandy loamy. The lowest soil bulk density of 1.34 and 1.20 g cm-3 were obtained in the unburnt dumpsite in 2007 and 2008 resulting to 12% and 20% decline in 2007 and 2008 in the unburnt dumpsite relative to cropped land. The total porosity and gravimetric moisture content was a reverse of the soil bulk density. Higher total porosity and gravimetric moisture content were obtained in the unburnt and burnt dumpsites in that order relative to the fallow and cropped land. Infiltration rate followed the same trends as total porosity of the various sites. The lowest infiltration rate 15.02 and 35.82 mmhr-1 was observed in the cropped land. The soil pH decreased with depth in the dump and non-dumpsite but became strongly acid at 30 – 60 cm and 60 – 90 cm depths. The order of soil organic matter content was unburnt dumpsite > burnt dumpsite > fallow > cropped land. The available P and exchangeable K and Ca were highest in the burnt dumpsite. Heavy metals (Zn, Cu, Fe, and Pb) increased with time in the burnt and unburnt dumpsites but decreased in the cropped land. More concentration of heavy metals was observed in the 0 – 30 cm soil depth. The relative performance of maize grown on soils of the dump and non-dumpsites showed that there was better growth in the dump sites soils. However, the concentrations of heavy metals on tissue were found to be within normal range. Therefore, long term dumping of sawmill waste can influence soil properties and productivity