Substratos e adubação nitrogenada na produção de mudas de maracujazeiro 'amarelo'

Abstract

The production of yellow passion fruit tree seedlings of high genetic, phytosanitary quality, well nourished and early is of outstanding importance both for taking on and for survival in the field. The development of the seedling depends on a few preponderant factors linked specifically to substrates and complementation with fertilizations. To try to minimize those problems and offer alternatives in the seed propagation of the yellow passion fruit tree, the present experiment was proposed aiming at seedling production in two different substrates with different nitrogen topdressing in the form of urea. This work was set up and conducted in the screening of the seedling nursery in the orchard of the Universidade Federal de Lavras (UFLA) in the town of Lavras - MG. Five doses of nitrogen (0; 400; 800; 1,600 and 3,200 mg N) dm-3 of substrate and two compositions of substrates : A (organic compound + urea + soil at the ration of 1:1:3 in volume) and B (Plantmax + urea + soil at the ratio of 1: 1: 3 in volume) were tested. The randomized block experimental design in factorial scheme 5) doses of nitrogen) x 2 (substrates A and B) with four replicates and 5 plants per plot. Past 120 days after sowing, the following characteristics were evaluated: length of the shoot (cm); root length (cm), shoot, root and total dry matter of the shoot, of the root and total (g/plant). It was found that use of nitrogen topdressing of up to 2,000mg N dm-3 warrant a better quality in the formation of yellow passion fruit tree seedlings. Substrate B (with Plantmax + urea + soil) promoted a better development of the yellow passion fruit tree seedlings as compared with substrate A (organic compound + urea + soil).