ABSTRACT Fertilization is important for the optimization of plant growth and yield, which are necessary for agronomic activities. Soil fertilization should increase net earnings that depend on nutrient use efficiency. The aim of this study was to evaluate the agronomic efficiency of eggplant under different doses of potassium (K) and nitrogen (N). Four levels of K (0, 54, 108, and 216 kg ha-1) and four levels of N (0, 67, 134, and 268 kg ha-1) were applied weekly by fertigation. The highest plant and the largest stem diameter were found with 165-175 kg ha-1 of N. Leaf area was more influenced by N than by K. Isolated application of different K doses did not statistically influence height plant, stem diameter, or leaf dry matter. The agronomic efficiency of nitrogen is reduced with increasing levels of N and K. | RESUMO A adubação é importante para otimizar o crescimento e produtividade, sendo necessario para atividade agrícola. A adubação de solo deve aumentar o lucro líquido, que depende da eficiência de uso de nutrientes pela planta. O objetivo deste estudo foi avaliar a eficiência agronômica em berinjela sob diferentes doses de potássio (K) e nitrogênio (N). Quatro níveis de K (0, 54, 108 e 216 kg de K ha-1) e quatro níveis de N (0, 67, 134 e 268 kg de N ha-1) foram aplicados semanalmente via fertirrigação. As plantas mais altas e com maior diâmetro de caule foram obtidas com 165-175 kg ha-1 de N. A área foliar foi mais influenciada pelo nitrogênio em comparação com o potássio. Aplicações isoladas de diferentes doses de K não influenciaram a altura de planta, diâmetro de caule e matéria seca da folha. A eficiência agronômica do nitrogênio é reduzida com o aumento da dose de N e K.

Fertilization is important for the optimization of plant growth and yield, which are necessary for agronomic activities. Soil fertilization should increase net earnings that depend on nutrient use efficiency. The aim of this study was to evaluate the agronomic efficiency of eggplant under different doses of potassium (K) and nitrogen (N). Four levels of K (0, 54, 108, and 216 kg ha-1) and four levels of N (0, 67, 134, and 268 kg ha-1) were applied weekly by fertigation. The highest plant and the largest stem diameter were found with 165-175 kg ha-1 of N. Leaf area was more influenced by N than by K. Isolated application of different K doses did not statistically influence height plant, stem diameter, or leaf dry matter. The agronomic efficiency of nitrogen is reduced with increasing levels of N and K.