Growth, Yield and Nitrogen Utilization Efficiency of Quinoa (Chenopodium quinoa) under Different Rates and Methods of Nitrogen Fertilization

TWO FIELD experiments were carried out in Tigzerti Research Station of Siwa Oasis, Desert Research Center, during two successive winter seasons of 2008 and 2009 to study growth, yield, yield components and N utilization efficiency of the pseudocereal quinoa (Chenopodium quinoa) under different rates and methods of N fertilization. Nitrogen fertilizer treatments were applied at four N rates of mineral fertilizer at the rate of 10 kg N/fed (as the control), 60, 80 and 100 kg N/fed; three split up doses of half the rates of mineral nitrogen (30, 40 and 50 kg N/fed with 10 m(3) of organic manure for each as soil application) and foliar application of nitrogen at the concentrations 1, 2 and 3%. The results indicated that plant height, number of basal branches and grain yield/fed were gradually increased with increasing the rate of nitrogen fertilizer up to the highest whether in case of mineral application only, or in split dose of mineral with organic nitrogen or when nitrogen was applied as foliar spray. Data also revealed that while the split dose of mineral with organic treatments was associated with highest values of these traits, foliar spray with nitrogen resulted in least values. The effect of the treatment imposed on nitrogen, protein, phosphorus and potassium contents in quinoa grains followed the general tendency of the treatment effect on growth and yield. N use efficiency was decreased with increasing mineral or foliar spray. On the other hand, there were relative increases in (NUE) when half mineral N dose with organic manure was applied. Foliar application was associated with lower response as compared with other methods.