Understanding seedling nutrition and the use of appropriate substrata for cultivation are essential to define fertilization recommendations. Due to the difficulty in making specific fertilization recommendations, the effect of nitrogen fertilization was tested on the growth and quality of sete-cascas (Samanea inopinata) seedlings. The experiment consisted of nine treatments with three repetitions each and six plastic bags per parcel, in randomized block design. The nitrogen source was ammonium sulfate applied at different levels every 14 or 28 days. The experiment was monitored for twelve months, and then harvested. The following parameters were evaluated: height (H), root collar diameter (D), dry matter of aerial part (MSPA) and root (MSR), total dry matter (MST) and seedling quality indexes H/D, H/MSPA, MSPA/MSR and IQD were calculated. The data were analyzed using factorial and regression analysis. All the tested morphological parameters were significantly affected by the nitrogen fertilization, except for the MSPA/MSR and H/D indexes. Due to the height and diameter importance, it was recommended 0.91 g of ammonium sulfate per seedling every 14 days when cultivated in Red-Yellow Latosol, combined with organic compost.
nitrogen; plant nutrition; native forest species; seedling production
