Nitrogen Fertilizer and Cultivar Effects on Yield and Nitrogen‐Use Efficiency of Grain Amaranth

Knowledge of fertility requirements or nitrogen-use efficiency of amaranth (Amaranthus spp.) cultivars is limited. The objectives of this research were to determine the response of grain amaranth to applied N, P, and K, and to determine the effect of cultivar and fertilizer N on nitrogen-use efficiency. Two field experiments were conducted. In the first, five rates of N, P, and K were applied in a central composite design with the cultivar Plainsman grown in five environments. In a second experiment, six amaranth cultivars, Amont, K266, K283, Plainsman, K432 and D136, were grown in three environments with five N rates (0, 45, 90, 135, and 180 kg N ha −1 ) []