EFFECTS OF CaCO₃ AND P ADDITIONS ON CORN (Zea mays L.) GROWTH AND NUTRIENT AVAILABILITY OF A PODZOLIC SOIL

A surface horizon from a Humo-Ferric Podzol was amended with 0 to 6 cmol kg−1 of CaCO3 and 125 to 500 mg P kg−1 to investigate their effects on the elemental composition and growth of corn and on nutrient availability. The addition of CaCO3 decreased the amounts of extractable P and Mn in the soil and the concentrations of P, K, Mn, Mg and Zn in the plants. The addition of P increased the dry matter yields, the amounts of available P in the soil and the concentrations of P and Mg in the plants, but decreased the concentrations of K, Mn and Zn in the seedlings. There were significant CaCO3 × P interactions on the amounts of extractable Mg and Zn in the soil and on the contents of N and Mn in the seedlings. The addition of 0.5 cmol CaCO3 kg−1 was beneficial to dry matter accumulation, but additions greater than 4 cmol kg−1 were excessive. The dry matter yields were most closely related to the amount of extractable P and to the activity of Mn2+ in solution. The concentration of P in the plants was very closely related to the amount of NaHCO3-extractable P in the soil. The concentration of Zn in the seedlings was most closely related to the amounts of DTPA-extractable Zn and of NaHCO3-extractable P. Key words: Liming, P fertilization, Zea mays (L.), plant nutrition, soil solution, Podzol