Fertilization Impacts on the Yield and Nutritional Status of Maize (Zea mays L.)

Maize (OsSK552 hybrid) was grown under field conditions on two hydromorphic soils of moderate fertility for two growing seasons. Increased rates of P and K (monoammonium phosphate and potassium chloride) were applied as follows: a) control (standard fertilization); b) a + 1500 kg P2O5 ha−1; c) a + 1500 kg K2O ha−1; d) = b + c. Residual effects of ameliorative fertilization were tested in the following year (2002) and the experiment was fertilized uniformly (kg ha−1: 177 N + 100 P2O5 + 150 K2O). The treatments were laid out according to the randomized block scheme with four replications. At the beginning of the silking stage, ear leaves were taken for chemical analyses. Maize growing on Luzani soil resulted in 15% lower yield compared to the Kobas experiment (7.75 and 9.06 t ha−1, respectively). Fertilization had a significant influence on the nutritional status of maize. For example, in comparison with the control, under the influence of P fertilization leaf P, Ca and Mg increased by 25%, 20% and 22%, respectively, while leaf Mg decreased by 10%. K fertilization decreased leaf Mg, Ca and P by 30%, 13% and 7%, respectively, while leaf K increased by 16%. Application of both P and K resulted in increases of leaf P and K by 14 and 15%, respectively, while leaf Ca and Mg decreased by 5% and as much as 30%, respectively.