Nitrogen Nutrition and Adaptation of Halophyte Chenopodium quinoa to Salt Stress

There is little evidence that the nitrogen nutrition supply at rates above or less than what is considered optimal in non-saline conditions improves growth and yield of halophyte crop cultivated under salt stress. Therefore, hypothesize of the present work was to find out the magnitude to which N could restore the harmful effects of salt stress on quinoa plants. A pot experiment was performed in greenhouse conditions to evaluate quinoa's response grown under water salinity treatments (0.0 & 200 mM NaCl) when nitrogen nutrition rates were limiting (50ppm), adequate (250 ppm), and excess (450 ppm) to guide proper application rate of nitrogen fertilizer under salinity stress. The results indicated that, salinity caused a significant decrease in the vegetative growth of the plant. Consequently, all vegetative measurements were negatively affected. As a result, the seed yield decreased to more than 50%. The application of a moderate level of nitrogen (250 ppm) caused a significant ameliorative effect on seed yield by 126% under non saline conditions and 34.5 % under saline conditions compared to the low nitrogen level. The results did not improve any further with the application of a higher level of nitrogen. These results indicate that applying (N) in adequate may improve most traits and prove to be a physiological treatment to increase resistance against the negative effects of salt stress in quinoa.