Effects of potassium fertilization and commercial substrates on development of passion fruit seedlings under greenhouse condition

The aim of this work was to evaluate commercially available substrates and levels of potassium on the development of passion fruit seedlings in protected conditions. The experiment was conducted at the city of Presidente Prudente, São Paulo within the period from April to September of 2010. The treatments were made with three different substrates (Bioplant ® , Coconut fiber and Vivatto ® ) and four levels of potassium (0, 150, 300 and 600 mg -1 of K dm 3), arranged in a 3 × 4 factorial design with five repetitions. The following parameters were analyzed 120 days after seedlings transplanting: Plant height, number of leaves, length of root, dry matter of shoot, root, total matter and chlorophyll content. The dose of 600 mg dm -3 of K provided the highest seedling height, 85.83 cm independent of the substrate. The commercial substrates Bioplant ® and Coconut fiber with a dose of 150 mg dm -3 of K influenced the maximum accumulation of total dry matter of seedlings. However, Vivatto ® substrate provided the highest accumulation of total dry matter with application dose of 600 mg dm -3 of K. Mineral potassium fertilization in the substrate Bioplant ® and Coconut fiber with a dose of 150 mg dm -3 reduced the length of passion fruit’s roots.