Resposta da cana-de-açúcar a adubação nitrogenada no brejo paraibano

Abstract

Nitrogen is one of the key nutrients essential for the highest growth and yield of agricultural crops. Among crops, sugarcane needs nitrogen to increase productivity. Thus, the objective of the research was to evaluate the effect of nitrogen doses on the development, gas exchange and productivity of sugarcane in Brejo Paraibano. The research was carried out in an experimental area belonging to the Department of Plant Science and Environmental Sciences of the Federal University of Paraíba, Campus II, located in the municipality of Areia, in the micro-region of Brejo and mesoregion of Agreste Paraibano, state of Paraíba, Brazil. The experimental design used was randomized blocks (DBC) with five treatments and four replications. The treatments were: 0 kg of N ha-1 (T1) (control), 62.5 + 62.5 kg of N ha-1 (planting and 30 DAP) (T2), 125 kg of N ha-1 (T3 ), 125 + 125 kg of N ha-1 (planting and 30 DAP) (T4) and 250 kg of N ha-1 (T5). Growth evaluations were performed at 180, 230 and 265 days after planting (DAP), where plant height, stem diameter, number of leaves per plant, number of tillers and number of internodes were analyzed. Gas exchange evaluations were performed at 265 days after planting, in which the net photosynthesis rate, stomatal conductance, transpiration and internal carbon concentration were measured. The data were submitted to analysis of variance (F test) and then the mean values were calculated with confidence intervals with a probability of 95%. According to the results obtained, it was found that the nitrogen doses did not interfere in the development, gas exchange and productivity of sugarcane in the Brejo Paraibano region.