Potassium fertirrigation of strawberry crop in Ceara

This study was aimed at evaluating the effects of potassium doses applied by fertigation on biomass accumulation and yield performance of strawberry cultivars in the Ceara coast. The experiment was conducted in full sunlight, in the interval from April to August 2012, in Fortaleza, Ceara. Treatments were disposed in a randomized blocks design, in a 2x5 factorial arrangement, consisting of five potassium doses (0.65, 0.97, 1.29, 1.61 and 1.93 g plant per week) and two strawberry cultivars (Oso Grande and Verao), with five replicates. At the 40th day after transplanting, the fruit harvesting started. The fruits were evaluated weekly, relatively to the the number of fruits per plant, fruit diameter, fruit length, average fruit weight and, at the end of the harvest period, the total yield. Potassium fertilization stimulates the production of dry matter of shoot and root for strawberry cultivars Oso grande and Verao. A potassium dose of 0.65 g plant-1 was the most efficient potassium dose (for fruit number per plant) for the Oso Grande cultivar and (for the average fruit weight) for the Verao cultivar. Increased potassium concentration reduces the yield of strawberry cultivars Oso grande and Verao. The Oso grande cultivar has higher adaptability to climatic conditions of Ceara than Verao.