Effect of Nitrogen Fertilizer Rates and Its Split Application on Yield and Nitrogen Use Efficiency of Quinoa (Chenopodium quinoa willd.) Cultivars

To evaluate the effect of nitrogen rate and its split application on seed yield and nitrogrn use efficiency (NUE) of quinoa cultivars, experiments were performed during 2018-2019 and 2019-2020 growing seasons as factor split plot based on randomized complete block design with three repetitions at Khuzestan Agricultural and Natural Resources Research and Training Center Station. Experiment treatments were nitrogen fertilizer (0, 100, 200 and 300 kg.ha-1) as the main factor and four levels of split nitrogen fertilizer applications (50% basic + 50% six-leaf, 50% basic + 25% Six-leaf percentage + 25% mid-flowering, 25% basic + 50% six-leaf + 25% mid-flowering and 25% basic + 25% six-leaf + 50% mid-flowering) and three cultivars of quinoa (Gizat, Q26, Titicaca) as sub-plot. The results showed, SPAD, height plant, number of plant branches, number of panicules per area unit and seeds per panicule as influenced by nitrogen content × split × cultivare, interaction. The years× nitrogen rate×split application× cultivar intractions were significant on plant height, 1000 seed weight, seed yield, biological yields, harvest index and NUE. The highest seed yield under all different levels of nitrogen was related to cultivar Q26, in both years by the use of 200 kg of nitrogen, the highest seed yield in the first year belonged to at 25% base application + 50% at six-leaf stage+ 25% at mid-flowering stage and in the second year, to at 50% as base application+ 25% at six-leaf stage+ 25% mid-flowering stage. Highest NUE belonged to Gizal (52.8 g.kg-1) and Q26 (51.8 g.kg-1) cultvars from 200 kg.ha-1 nitrogen by split applications of 25% base + 25% at six-leaf stage+ 50% at mid-flowering stage, while in second year from 100 kg.ha-1 nitrogen. In general, climatic conditions and split application of fertilizer were effective roles in increasing the efficiency of nitrogen consumption. Thus by the use of proper management seed yield can be increased and the risk of its production decreased.