Nitrogen Management in Maize Under Rainfed Conditions in the Brazilian Semiarid Region

Zea mays L. presents socioeconomic and cultural importance for the Northeast region of Brazil, its yield is directly related to the productive system, to the edaphoclimatic conditions and to the soil management. The aim of this work was to evaluate the development and the yield of maize under different nitrogen doses in rainfed conditions in the Brazilian semiarid. The experimental design was in randomized blocks, with four treatments and five replications, totalizing 20 experimental plots, with 24 plants each. The treatments were: T1 (0 kg ha-1 of N); T2 (40 kg ha-1 of N); T3 (60 kg ha-1 of N) and T4 (80 kg ha-1 of N). Were evaluated: plant height, culm diameter and number of leaves at 30, 45, 60, 75 and 90 days after emergence; leaf temperature, stomatal conductance, transpiration, liquid photosynthesis and intercellular carbon concentration at 65 days after emergence; yield, shoot dry mass and nitrogen content in the soil after harvest. The different nitrogen doses significantly influenced the plant height, culm diameter and the number of leaves in the different evaluation periods, also influencing the nitrogen levels in the soil after the harvest. There was no difference among treatments for the yield, the registered average was 5,205 kg ha-1. The development of the crop and the nitrogen absorption may have been influenced by the water deficit during the crop cycle. The maize presented better agronomic performance with the dose of 60 kg ha-1 of nitrogen.