No abstract

A phosphorus (P) greenhouse experiment was carried out with maize (Zea Mays L.) using surface horizons of three contrasted acid soils from southern Cameroon. The objectives were (i) to assess causal factors of maize differential growth and P uptake and (ii) to explore plant-soil interactions in acid soils under increasing P supply. Shoot and root dry-matter yield and P uptake were significantly influenced by soil type and P rate (P , 0.000), but the interaction was not significant. Soil properties that significantly (P , 0.05) influenced maize growth variables were available P, soil pH, exchangeable bases [calcium (Ca), magnesium (Mg)], and exchangeable aluminium (Al). Data ordination through principal-component analysis highlighted a four-component model that accounted for 88.1% of total system variance (TSV) and summarized plant reaction in acid soil condition. The first component, associated with 36.1% of TSV, pointed at increasing root-shoot ratio with increasing soil acidity and exchangeable Al. The second component (24.6% of TSV) highlighted soil labile P pool increase as a function of P rate. The third and fourth components reflected nitrogen (N) accumulation in soils and soil texture variability, respectively.