Yield and nitrogen utilization efficiency of the pseudocereals amaranth, quinoa, and buckwheat under differing nitrogen fertilization

Abstract

In recent years, the cultivation of the pseudocereal species amaranth, quinoa, and buckwheat has gained rising attention. This study was undertaken to explore nitrogen (N) fertility requirements and nitrogen use efficiency of these species. For this purpose, a 2-year field experiment with N rates of 0, 80, and 120 kg N ha-1 for amaranth and quinoa and 0, 30, and 60 kg N ha -1 for buckwheat and two cultivars of each species was conducted. Grain yield of amaranth responded to N and ranged between 1986 and 2767 kg ha-1. Nitrogen utilization efficiency (NUtE) ranged from 13.9 to 15.4 kg grain yield per kg above-ground plant N and decreased with increasing N rate. Higher grain yields and NUtEs seemed to be mainly inhibited by the low harvest index (0.22-0.23) of the investigated amaranth cultivars. Quinoa yielded between 1790 and 3495 kg grain ha-1 and responded strongly to N fertilization. NUtE averaged 22.2 kg kg-1 and did not decrease with increasing N rates. The grain yield of buckwheat did not respond to N fertilization and averaged 1425 kg ha-1. N uptake increased only slightly with N fertilization. NUtE ranged from 16.1 to 20.0 kg kg-1. Main problems occurring with the application of N to buckwheat were grain scattering and lodging. © 2004 Elsevier B.V. All rights reserved.