Effect of Different Nitrogen Fertilizer Rates and Sources on Vegetative Growth and Yield of Quinoa Plant as a Newly Leafy Vegetable Crop

Abstract

Quinoa (Chenopodium quinoa Willd.) is a pseudocereal that has been cultivated in the Andean region for thousands of years. It is considered as a new non-traditional leafy vegetable crop newly introduced to Egypt. Nitrogen is more important than any other elements for plant growth. It plays a vital role in the growth, yield and nutritional quality of leafy vegetable crops. In order to evaluate the influence of two sources of nitrogen (ammonium sulfate 20.6% and calcium nitrate 15.5%) used at rates of 40, 60 and 80 kg N/fed. on vegetative growth and productivity of two quinoa cultivars Cica and Hualhuas harvested after 40 days from sowing date. A field experiment was carried out at the during the two winter seasons of 2015 and 2016. The treatments were arranged in a split plot design, with three replicates. The obtained results showed that Cica cultivar was superior to Hualhuas concerning all vegetative growth parameters and yield except for leaf area in both seasons of the study. Regarding nitrogen rates and sources, quinoa plants received 80 kg N/fed. from ammonium sulfate or calcium nitrate recorded the highest values of plant length, leaf area, plant fresh and dry weights, and fresh and dry weights of leaves/plant, as well as leaf moisture content without significant differences between the two nitrogen sources. On the other hand, the lowest values were recorded by 40 kg N/fed. from ammonium sulfate or calcium nitrate except for number of leaves/plant in both seasons and leaf moisture content in the second season. However, no significant differences were detected among all nitrogen treatments (rates or sources) on the number of leaves/plant. A higher significant yield was attained by ammonium sulfate at 80 kg N/fed. in relative to the rest of nitrogen treatments. Concerning the interaction effect, the results clearly revealed that Cica plants received calcium nitrate at 80 kg N/fed. gave the highest values of plant length. Furthermore, Cica plants treated with 80 kg N/ fed. either from ammonium sulfate or calcium nitrate recorded significant increases in plant fresh and dry weights as well as yield without significant differences between them. On the other hand, the best values of leaf area were detected when Hualhuas plants were fertilized by 80 kg N/fed. from ammonium sulfate or calcium nitrate without significant difference between them. * N-NH4 + and N-NO3were added as ammonium sulfate (20.6%) and calcium nitrate (15.5%), respectively. Means into every group within a column followed by the same letter are not significantly different (P ≤ 0.05) according to Duncanʼs multiple range test.