Effect of Cassava Processing Effluent on Soil Properties, Growth and Yield of Maize (Zea mays L.) in South Eastern Nigeria.
A study, comprising a survey, greenhouse and field experiments was conducted to examine the effect of Cassava Processing Effluent (CPE) on soil chemical properties, maize growth performances and grain yield. In the survey, soil samples were taken (0-15 and 15 – 30cm) of CPE contaminated and non contaminated areas of rural cassava processing depots. Serial dilutions of CPE collected from these depots (80, 60, 40, 20, and 0% (water only) were made and used to water potted maize plants for 30 days and field-sown maize for 120 days. The survey showed that soil pH, exchangeable potassium (K) and sodium (Na) were 4, 40 and 53% respectively, greater in uncontaminated than in contaminated soil. Calcium (Ca), Magnesium (Mg), available phosphorus (P) and organic matter increased significantly (p < 0.05) in CPE contaminated soil by 20, 9, 10 and 8%, respectively when compared with uncontaminated soil. Results of greenhouse and field experiments showed that all maize growth performances and grain yield were best when dilutions were between 20 and 40% (effluent in water). Mineralization of nitrogen (N) was greatly enhanced in the soil where CPE was disposed of when compared with NH4-N and NO3- N contents of uncontaminated soil. Since only traces of hydrogen cyanide (HCN) were analyzed in the soil at the end of the experiments (within recommended safe level of 5 mg kg-1) indicating that CPE is highly degradable.
Keywords: Cassava processing effluent, Soil properties, Hydrogen cyanide, growth, yield, maize, Southeastern Nigeria.