In one study, there was an increase in exchangeable calcium in a dystrophic Entisol soil fertilized with different doses of cassava waste water (0; 12.5; 25.0; 45.0; and 65.0 m3 ha−1 ) and planted with lettuce, achieving a maximum concentra tion of 1.55 cmolc dm−3 due to the application of 65 m3 ha−1 [3]. The levels of exchangeable calcium, magnesium, and sodium in soils located in rural areas close to the Niger Delta, Nigeria, increased during the study period (6 months) due to the disposal of cassava waste water “in natura” in the environment [5].