Sorghum growth in acid soils of West Africa: Variations in soil chemical properties

Three field experiments were conducted to alleviate soil chemical properties associated;ted with poor early growth of sorghum [Sorghum bicolor (L.) Moench] in selected Grossarenic and Plinthic Paleustalfs or Eutric Nitosols of subhumid West Africa. These experiments were implemented for two growing;seasons on the same plots. Soil amendments used (lime, manure, Tilemsi phosphate rock, and water-soluble P source) significantly increased soil pH (5.1-7.8), decreased exchangeable Al3+ (0.48-0 cmol(c) kg(-1)), and increased Bray-l P content (7.1-48.5 mg kg(-1)), organic C content (0.19-0.51), and ECEC (1.30-3.10 cmol(c) kg(-1)). The net effects of such improvements were excellent sorghum growth and yield in the first growing season. However, most sorghum seedlings failed to grow in the second growing season. Affected sorghum seedlings had deficient contents of P (<2 g kg(-1)) and Al contents higher (more than twofold) than the toxic level of 500 mg Al kg(-1). These suggest that P deficiency and Al toxicity may be associated with reduced sorghum growth in these soils. The short-term sorghum response to amendments and fertilizers suggests that the simple technology of lining may be an inadequate prescription for managing these acid soils.