Investigation of the Effect of Different Amounts of Nitrogen Fertilizer on Yield, Yield Components and Nitrogen Use Efficiency of Two Quinoa (Chenopodium quinoa Willd.) Cultivars in Southern Khuzestan Province

Salinity is one of the most important environmental stresses that affect crop production. In all areas where irrigation is essential for crop production, soil salinity is inevitable . This phenomenon has gradually become a major problem in arid and semi-arid regions of Iran. Among the strategies to deal with abiotic stresses are the development of salinity tolerant cultivars, crop rotation, genetic modification, use of appropriate organic and chemical fertilizers. Quinoa is a promising species of halophyte that has the potential to become a crop. Quinoa, scientifically known as Chenopodium quinoa willd, is a dicotyledonous plant belonging to the Chenopodiaceae family of spinach and is often self-pollinating. Salinity stress has great effects on plant growth, seed quality and grain yield even in saline plants such as quinoa. Due to plant growth salinity, total grain yield, number of seeds, fresh and dry weight of seeds are reduced. Nitrogen is one of the essential nutrients for plant growth. Nitrogen fertilizers play an essential role in increasing yield as well as improving grain quality. Quinoa needs a lot of soil nitrogen and the use of nitrogen fertilizer is very important for crop growth during the vegetative growth period of quinoa.Quinoa cultivation, especially by using drainage in the southern regions of Iran as a salinity-resistant crop, will lead to diversification of crops, sustainable production, and increase farmers' incomes and food security. Considering that agriculture and supply of nitrogen required by the plant is very important in order to increase crop production with optimal yield, the amount of fertilizer used and also the appropriate cultivar need to be investigated and a step to determine the best cultivar and the best level of nitrogen fertilizer and its effect on yield, yield components, grain protein concentration and efficiency of nitrogen application under irrigation conditions of sugarcane fields in the south of Khuzestan province.

This research was carried out in field conditions in the 97th crop year in Mirza Kuchak Khan Sugarcane Cultivation and Industry Company in the form of split plots in a randomized complete block design with three replications. Factors include urea fertilizer at four levels: 0 (control), 75, 150, 225 kg / ha) as the main factor and two quinoa cultivars (Titi Kaka: V1 and Gizavan: V2) as the secondary factor in Was considered.

The results showed that the interaction of nitrogen and cultivar on leaf area index, number of inflorescences per plant, grain yield, biological yield and grain protein were significant. The highest plant height, stem diameter and leaf area index belonged to 225 kg N / ha. The highest grain yield in Gizavan cultivar (2363 kg / ha) was obtained at the level of 150 kg N / ha and then decreased, but in Titi Kaka cultivar the highest grain yield (2372 kg / ha) was obtained at the level of 225 kg N / ha. Obtained and the reaction was linearly reduced to the highest level of nitrogen fertilizer. The highest amount of grain protein was observed in Gizavan cultivar with application of 150 kg N / ha, which was 138% higher than the control treatment. Based on the obtained results, Gizavan Quinoa cultivar can be a very suitable choice for saline and low-yield fields in the south of Khuzestan province.

According to the results of the study, increasing the application of nitrogen fertilizer increased the yield and yield components and grain nitrogen. Application of 150 kg nitrogen per hectare in Gizavan cultivar with an average yield of 2.36 tons per hectare in the climate of southern Khuzestan province along with the application of drainage from sugarcane cultivation produced the highest grain yield. Quinoa due to its high genetic diversity and adaptation to different climates, high nutritional value and high efficiency of resource use, can be a suitable plant for the use of unconventional soil and water resources in the south of Khuzestan province. It is recommended that future tests be performed on quinoa at different locations with different cropping methods and other fertilizer levels to ensure that the results are relatively consistent over time.