Infuence of nitrogen fertilization on yield of amaranth

Abstract

This work was carried out to study the effect of nitrogen fertilization on grain amaranth yield, in Maringá, north of Paraná state. It was done in feld conditions, using a complete randomized design, with four treatments and three replicates. Seeds were sowed in lines, spaced each 0.5 m. Fertilization was done with NPK 10-10-10 (350 kg/ha). Fifteen days after germination there was left a population of 20 plants m-1. Thirty days after germination felds received nitrogen fertilizer (urea, 45% N), and doses were 0; 50; 100; 200 kg N ha-1. Plants were cut 114 days after germination, to measure the following parameters: plant height; stem diameter; fresh and dry biomass yield of stems and leaves; and seed yield. Plant height and grain production showed quadratic response. Stem diameter showed no differences. Biomass production (fresh and dry) showed linear response. Yield of amaranth grains answered positively to nitrogen fertilization.