An incubation study was conducted with 3 soils (I, II, and III with 12, 66, and 94 mg/kg Bray-1 P), 4 manure treatments (1 untreated; 3 chemically [alum – Al; FeCl3 – Fe, lime – Ca] treated) and 1 fertilizer (mono-calcium phosphate, MCP) treatment, at 2 rates (12.5 and 25 mg P/kg soil), and a control (no manure/fertilizer). Sub-samples were analyzed for water-soluble P (WSP) and Bray-1 P after each incubation period (1 d, 1 & 2 w, 1 and 3 months). Distribution of P among different fractions (soluble & exchangeable; Al-, Fe-, and Ca- bound; org-P; residual) was determined after 1 d reaction. WSP increased when soils received MCP and untreated or Catreated manure with the magnitude being proportional to the rate of P applied. WSP, however, decreased (compared to control) for soils II and III (high Bray-1 P) or increased slightly for soil I (low Bray-1 P) with application of Al or Fe-treated manure. WSP decreased sharply between 1 d and 1 or 2 w incubation and then remained relatively constant for up to 3 months. With respect to control, Bray-1 P increased for all treatment types and soils in proportion to the rate of P addition in the following order: MCP > Ca-treated > Al-treated ³ untreated > Fe-treated > control. Within each treatment, Bray-1 P decreased between 1 d and 1 or 2 w and then increased gradually for up to 3 months. Addition of Al or Fe treated manure decreases P solubility with the effect being more pronounced in soils with high background P. On the other hand, application of Ca-treated manure or MCP increases both WSP and bio-available P.