Dry matter yield and nutrient uptake in corn plants as a function of potassic fertilization and of basis soil saturation

The purpose of this research was to study dry matter yield and nutrients up take by corn plants as a function of potassic fertilization and of soil bas is saturation. An experiment was conducted under greenhouse conditions, usi ng an early single hybrid corn Zeneca 8392 grown in 30 L pots, tested with three types of soil (Quartzpsamment and two alic Dark-Red Latosol - Haplort hox), with two levels of basis saturation (40 and 70 %) and four levels of potassium content(0.5, 1.5, 3.0 and 6.0 mmol(c)dm(-3)). A completely random design with four replications was utilized. The basis saturation treatment s were calibrated by liming the soils with a mixture of 4: 1 of calcium and magnesium carbonate, according to soil type. K content in the soil was est ablished by applying 0, 3.62, 7.24 and 14.48 g of KCl per 30 L pot. P (200 mg kg(-1)) and Zn (5 mg kg(-1)) were applied to all treatments at sowing ti me. N was applied at sowing time (83.7 mg kg(-1)) as well as at top dressin g, 25 and 40 days after seedling emergence, totalizing 200 mg kg(-1). Sixty days after seedling emergence the dry matter weight and N, P, K, Ca and Mg content of the leaves and stems were determined. The dry matter yield was increased by K concentrations in the soil up to 1.5 mmol(c)dm(-3). The incr ease in soil K levels allowed decrease on the Ca and Mg concentrations in c orn dry matter. The increase of basis saturation and soil Ca and Mg levels decrease corn plant K uptake.