Crescimento e qualidade de mudas de jucá submetidas a doses de nitrogênio

Abstract

The demand for native species has increased due to its economic importance in several areas, such as: medicine, construction, animal feeding, ornamentation and recovery of degraded areas etc., however, there are difficulties in recommending these plants due to the lack of knowledge of the nutritional requirements during the seedling formation phase. Therefore, the objective of this work was to evaluate the nitrogen rates of initial growth and quality of jucá seedlings (libidibia ferrea (Mart. Ex Tul.) Var. Ferrea). The experiment was carried out in a 50% shade area of agricultural screen at the Nucleus of Education and Research in Urban Agriculture (NEPAU), belonging to the Plant Science Department of the Agricultural Sciences Center of the Federal University of Ceará (UFC). The experiment was carried out in a randomized block design, consisting of five nitrogen doses (30, 60, 90, 120 and 150mg dm-3), with five replicates and each experimental unit being composed by six plants. Twenty-one days after sowing (DAS), measurements of height and planting diameter were started. At seventy DAS, the plants were evaluated by evaluating their height (H), diameter (D) and aerial dry matter part (MSPA); and calculating the total dry matter (MST) and the H/D, MSPA/MSR ratios and the Dickson quality index (IQD); contents and accumulation of N, P and K in aerial parts and efficiency of utilization of these nutrients by the plant. These data were submitted to analysis of variance, means tests and regression analysis. All the evaluated characteristics were significantly affected by the doses of N, with the exception of MSPA, H/D ratio, levels and accumulation of P and efficiency of use of P and K. The species has low requirement of nitrogen, suggesting the dose of 54.3mg dm-3 as sufficient for satisfactory growth of jucá seedlings.