Abstract

The short term changes in the concentration of some of the major constituents of cassava waste water and their corresponding effects on some of the soil exchangeable cations were studied following surface application of cassava waste water. The leaching experiment with de – ionized water was carried out on soil inside column under conditions of saturated flow. Samples of leachate were taken at 10 cm interval down the soil columns and were analyzed for NO₃^-, Cl^-, Ca²⁺, Mg²⁺ and Na⁺. After the column leaching, soil samples were collected from the columns at the depth of 10, 20, 30, 40 and 50 cm for the analysis of pH, soil organic matter and some exchangeable cations. Cassava waste water application caused a distinct decrease in the concentrations of the anions and cations introduced through the waste water. However, concentration of the anion in the samples of the leachate collected down the soil columns on the average decreased with the depth of the soil column while the concentration of the cations increased with the depth of the column. The application of cassava waste water also caused a distinct rise in soil organic matter at all the depths of sampling. However, the application resulted in a distinct fall in the soil pH. Highest values of soil pH were observed at 0 to 10 cm depth while the lowest were observed at 10 to 20 cm depth for the control, 5 and 10 days resident time experiments. The highest Na⁺ concentration of 0.75 cmol/kg was observed at the soil depth of 20 cm while the lowest (0.47 cmol/kg) was at 10 cm soil depth. The highest soil Ca²⁺concentration of 2.80 cmol/kg was at the soil depth of 20 cm while the lowest concentration of 2.60 cmol/kg was at the soil depth of 30 cm. The lowest soil Mg²⁺ concentration of 0.34 cmol/kg was at the depth of 10 cm while the highest of 0.72 cmol/kg was at the depth of 50 cm.

Key words: Short term, cassava, wastewater, chemical properties, loamy sand soil.