Potassium, calcium, and magnesium mineralization in manure-treated soils

Studies into cation release in manured soils are very limited and poorly documented. The present investigation was therefore aimed at comparing the influence of manure application on cation [calcium (Ca), magnesium (Mg) and potassium (K)] mineralization in four different soils. Four sources of livestock manure: chicken manure (PM), cattle manure (CM), swine manure (SM), ostrich manure (OM) and a control (no manure) were added to the soils (Andosol, red-yellow soil, masa soil, and sandune soil) and incubated for 8 weeks at room temperature. Soils were sampled at weekly intervals and analyzed for pH, EC, and exchangeable Ca, Mg, and K. Soil pH increases ranging between 5.8 in CM and 6.6 in OM treatments were observed. Chicken manure increased EC from the mean initial level of 4.4 to 11.8 mS/m. Cumulative mineralized Ca and Mg was highest in red-yellow soil followed by masa soil. The lowest values for Ca (1.8 cmolc kg(-1)) and Mg (1.3 cmolc kg(-1)) were in Andosol.