عنوان مقاله [English]
Background and purpose: Quinoa (Chenopodium quinoa Willd.) is a plant from Amaranthaceae family that now considered an alternative to high-water plants, its high nutritional value and high adaptability to tolerate a wide range of biotic and abiotic stresses. Among the nutrients, nitrogen is the most important element that restricts plant growth and plays an important role in enhancing the quantitative and qualitative yield of crops. Selection of optimal crop density due to competition over water, food and light is one of the most important crop factors that has a significant impact on crop growth and yield. Due to the welcoming of farmers in Fars province for the development of cultivation of quinoa, this study was conducted to evaluate the interaction of nitrogen fertilizer and plant density on the growth and yield of quinoa in Mamassani city of Fars province.
Materials and Methods: The experiment was conducted as split plot based on randomized complete block design with three replications in September 2018 in Mamassani city of Fars province. The main factor was nitrogen fertilizer at four levels (0, 60, 120 and 180 kg ha-1 from urea source) and the sub-factor was planting density at three levels (60, 80 and 100 plants m-2). The harvesting operation was carried out on December 10. In this experiment, plant height, number of lateral branches and length of panicle were measured through 5 randomly sampled plots. For determination of biological yield and grain yield, two square meters of each unit were harvested with respect to marginal effect. In order to estimate growth indices, two middle rows from the middle of each plot were removed by liminating the marginal effect. The first sampling was performed 14 days after planting and subsequent sampling was performed at intervals once evry 14 days until the end of plant growth.
Results: The results showed that nitrogen fertilizer had a significant effect on increasing plant height, number of lateral branches and panicle length. Increasing plant density decreased the number of lateral branches and the length of panicle. Increasing nitrogen and plant density increased plant height, grain yield, biological yield and 1000 grain weight. The highest leaf area index, crop growth rate and total dry matter accumulation were obtained at the highest level of fertilizer and plant density.
Conclusion: Due to the superiority of 180 kg of nitrogen level and density of 100 plants per square meter in terms of grain yield, harvest index, leaf area index and crop growth rate, it seems that these amounts of nitrogen fertilizer and planting density can be recommended for proper performance in the test area and similar areas.