Ecophysiological aspects of Tachigali vulgaris seedlings using different sources and doses of nitrogen

Abstract

This study aimed to evaluate the effects of sources and increasing doses of nitrogen on growth and gas exchange in plants of Tachigali vulgaris. The experiment was conducted in a greenhouse in the period from April to July 2015. The experimental design was randomized blocks in a factorial scheme (4 x 5), corresponding to 4 sources and 5 doses with four replications. The seedlings were grown in pots containing 3 dm 3 of soil. Nitrogen sources such as urea [(NH₂)₂CO], ammonium nitrate (NH4NO3), ammonium sulfate [(NH4) 2SO4] and calcium nitrate [Ca (NO3)2] were tested in five doses of 0, 75, 150, 225 and 300 mg/dm³. They were applied as a solution in four portions, 25, 50, 75 and 100 days after transplanting. The lower growth of cultivated plants may be associated with N-NH 4 + and lower photosynthetic activity, especially due to negative action of this ion on stomatal conductance. The occurrence of this ion resulted in lower growth and biomass production. Based on the results, for the production of tachibranco seedlings (Tachigali vulgaris) dose of 150 mg dm-3 of N applied in installments, 25, 50, 75 and 100 days, by applying ammonium nitrate is recommended.