Response of Quinoa (Chenopodium quinoa Willd) Plant to Nitrogen Fertilization and Irrigation by Saline Water

Abstract

The response of quinoa (Chenopodium quinoa Willd.) grown under salinity stress of irrigation water to nitrogen fertilization for improving yield production and quality was investigated. In plots experiment, application of 0 (N0), 14.28 (N1) and 28.56 (N2) g N m -2 as ammonium sulfate to quinoa (cultivar Regalona) sown in claytextured soil and irrigated by water of 0.65, 10 and 20 dS m -1 was studied. The results showed that application of nitrogen improved both biomass and seed yield. Nitrogen fertilization at rates of 14.28 and 28.56 g m -2 increased the yield of biomass by about 33.5 and 60% more than the control under fresh and 10 dS m -1 saline water irrigation. Under irrigation with 20 dS m -1 , N application by corresponded rates increased the biomass by 57 and 100%, respectively. Similar results were obtained with seed yield. Results of N content in seed and hay indicated that, under non-saline conditions, N content increased by 7.9 and 39.7% in hay and 15.9 and 36.8% in seeds over the control when the plant fertilized by 14.28 and 28.56 g N m -2 , respectively. Seed-N decreased by about 17.0, 5.2 and 8.0% in the plants irrigated with water of 10 dS m -1 and treated by N0, N1 and N2, respectively, whereas irrigation with 20 dS m -1 water decreased seed-N by 26.4, 10.4 and 17.7% in plants fertilized by N0, N1 and N2 respectively. Under nonsaline conditions, nitrogen utilization efficiency (NUtE) decreased from 55.1 to 47.5 and 40.3 kg seed kg -1 N in plants treated byN0, N1and N2. Similar trends were observed in the plants irrigated by higher levels of water salinity. The results indicated that quinoa hay yield responded to N application more than seed yield response. In N0-treated plants, NUtE increased from 55.1 to 66.2 and 74.7 kg seed/kg N in plants irrigated by water of 0.65, 10 and 20 dS m -1 , respectively. N fertilization with N1 and N2 did not influence Na and improved K content in the hay of plants irrigated by saline water (10 and 20 dS m -1 ). The use of quinoa hay as ruminant feed was supported by the results of both organic material content and high levels of crude protein as comparing to clover hay. However, the low percent of ether extract and higher percents of ADF and NDF lowered its quality. Therefore, it could be strong feed supplement for ruminants.