Cultivo de gladíolos em função das doses de calcário e potássio

Abstract

Cultivation of gladiolus in the Brazilian Savannah (locally known as Cerrado), a biome characterized by low fertility and high soil acidity, requires the use of lime and fertilizer, mainly potassium. The effect of lime and potassium rates was evaluated in the cultivation of gladiolus plants in an Oxisol (Typical Haplustox) from Cerrado, in Dourados municipality, Mato Grosso do Sul state. The experiment was carried out in the Univerdidade Federal da Grande Dourados. We adopted the randomized blocks design with four replications; the treatments were arranged in split-plots and the plots were composed of two plants of gladiolus cultivar Peter Pears, grown in plastic pots of 5 L. Thus, five rates of lime (0, 1, 2, 4 and 8 t ha -1) were applied to the main plots one month before planting and five K 2O rates (0, 20, 40, 80, and 160 kg ha -1) were applied to the sub-plots, using potassium chloride (KCl) as source. The length of the leaves, beginning of flowering, durability and number of flower buds, plant height and length of floral stalks were determined. After flowering, fresh weight, length and diameter of the corms and the nutrient content of the shoots were evaluated. The length of the leaves, beginning of flowering and durability of the flower buds were neither affected by liming, nor by fertilization with potassium. Excessive K and CaCO 3 doses were harmful to plant height, length of floral stalk and spike, and reduced the number of flower buds and the diameter of the corm. High concentrations of exchangeable K in the soil decreased absorption of magnesium by the plants. The studied rates of lime and potassium were not efficient for the production of gladiolus plants classified as extra large in the market.