ABSTRACT
Growth traits, yield, N content, photosynthetic pigments, ammonia and amino acids were measured to verify the effect of the interaction between N, Ni, and 2,4-D applied in the cotton crop. The objective was to study the hormonal effect of 2,4-D associated with the application of N and Ni in coverage to improve yield. The N (0, 40, 80, and 120 kg ha-1) and Ni(0, 300, 450, and 600 g ha-1) were applied to the soil in the square phenological growth stage. The commercial 2,4-D DMA® BR (0 and 1.8 g a.e ha-1) was applied to the leaves at the same growth stage. The supply of N in cover fertilization up to 120 kg ha-1 was beneficial for cotton, providing greater yield and content of photosynthetic pigments. The application of 2,4-D in a hormetic dose, as a synthetic auxin during the beginning of flowering, proved to be a promising technique to improve cotton yield. This end-of-cycle response is related to the requirement for auxins during the cotton fruiting process.
