Potentials of some cement by-products for liming of an acid soil in the humid zone of South-Western Cameroon.

Aluminium (Al) toxicity is the major limiting factor of plant growth in acid soils. A pot trial was carried out to evaluate the effects of lime (CaCO3) from three liming materials on soil Al toxicity and the yield of maize (Zea mays L.). Two cement by-products (Agri-56 and Filler) and a conventional liming material (Limbux) were used. The acid neutralizing values for Limbux, Agri-56 and Filler were 126, 88 and 34% CaCO3 equivalent, respectively. Five rates of lime equivalent: 0, 2, 4, 8 and 16 tons CaCO3 ha -1 and the three liming materials were applied in combinations as treatments. Agri-56 was as efficient as Limbux in neutralizing Al toxicity. Aluminium saturation decreased from 83% to 31, 37and 69% for Limbux, Agri-56 and Filler, respectively when 2 tons CaCO3 ha -1 was applied. Limbux and Agri-56 increased the soil pH from 4.3 to 7.1 and 6.5, respectively at equivalent rate of 16 tons CaCO3 ha -1 . There was a 53.5 and 67.2% increase in maize yield for Limbux and Agri-56, respectively when 2 tons CaCO3 ha -1 was applied. Because of its availability and easy to use, Agri-56 is therefore recommended as the liming material on the acid soils of South-western Cameroon.