Abstract

The research was carried out at Akwa Ibom State University Farm, Obio Akpa Campus to determine the effects of oil palm fruit processing effluent (POME) on selected soil properties . The treatments consisted of applications of the effluent on the slashed but unweeded plots over a period of 37weeks at the total rates of 0, 80, 160 and 240litres/plot in 3 replicates (equivalent to 0,400000,800000 and 120000L/Ha). The application was applied for the period of 2weeks and the experimental design was RCBD. The soil samples were collected from individual treatment plots at 3 month intervals to enable evaluations of changes in soil properties over time caused b the treatment, viz: bulk density, total porosity, organic matter, aggregate stability, field moisture capacity, permanent wilting point water available capacity and pH. A significant impact of POME   on soil properties was observed as treatment rates increased from o to 120000L/Ha. For almost all the soil parameters (organic matter, available, pH, Field capacity, PWP, AWC and bulk density) the effect of POME was more prominent on plots receiving 80 and 160 L of POME. The results indicated that POME increased soil acidity of plot receiving 80 liters of POME. Organic matter content of the soil increased significantly by 25% in plots receiving 160 L POME and 33.3% in plots with 240 L POME. Moisture content at FC among the treated plots were significantly (p<0.05) different.  Highly significant moisture at field capacity was recorded  in plots with 80 L POME (50.96%), followed by plot with 240 L (44.76%) and plots with 160 L POME (41.15%) was the least. Interestingly, 160 L of POME significantly decreased the field capacity moisture by 6%.  The magnitude of the aggregate size decreased with increase in POME and the trend was in order  of control (2.7%) < 240 L (4.7%)< 160 L (6.3%) < 80 L (7.3%).  The assessment of 1mm aggregate size, the results showed that plots with 80 L and 240 L POME were similar, but significantly higher than plots with 160 L and the control. Micro aggregates (0.5 and 0.25 mm) significantly dominated the stable aggregate to water at three months after application of POME. The 0.5 mm aggregates collapsed from 21.33% to 20% when 80 L of POME was applied. It further disaggregated to 18.33% with 160 L of POME and 19% with 240 L of POME. This showed that POME enhanced the disaggregation of micro aggregate in the soil should the POME treatment is allowed up to three months on the soil.