Evaluation of the Effect of Nitrogen Consumption and Use Efficiency on Yield and Yield Components of Two Potato Cultivars under Quchan Conditions

Nitrogen (N) is one of the main limiting factors in agroecosystems all around the world. However, high application rates of N fertilizers would lead to negative environmental consequences. Reduction of N fertilizers consumption decreases production costs and environmental pollution. Therefore, N efficiency to be enhanced due to the high N fertilizer cost and required measures to prevent the waste of N. Cultivation of diverse crop cultivars with higher resources absorption and utilization efficiency is one of the major approaches in sustainable agriculture that would result in the effective use of natural and chemical inputs and reduce significantly the environmental risks. Quchan City is one of the potato production poles in Khorasan Razavi province. In this region, large amounts of N fertilizers annually are consumed in the potato agroecosystem. Therefore, the potato of the present study was evaluating N uptake and utilization efficiency, and finally, N uses efficiency in the potato agroecosystem of Quchan.

This experiment was performed in the cropping year of 2020-21 in Quchan located in Khorasan Razavi province. A split plots arrangement based on a randomized complete block design with three replications was conducted. Different nitrogen application rates (0, 50, 100, and 150 kg of pure nitrogen per hectare) were assigned to the main plot and the sub-plot factor consisted of two potato cultivars, Agria and Arinda. To calculate the efficiency of nitrogen application, the amount of nitrogen in the soil was also considered. Equations (1 to 3) were used to calculate nitrogen efficiencies:                                                                                                       Eq. 1
                                                                                                        Eq. 2
                                                                                                    Eq. 3

The results of the analysis of variance showed that the effect of nitrogen fertilizer and cultivar on yield was significant. At the same levels of nitrogen, the Arinda cultivar had a higher yield and with increasing nitrogen application, an increase in yield was observed in both Agria and Arinda cultivars. The effect of nitrogen application and cultivar on nitrogen uptake, utilization, and use efficiency was significant (p≤0.01). Comparing the interaction of nitrogen and cultivar on nitrogen utilization efficiency, showed that the Arinda cultivar had higher efficiency than the Agria cultivar.

By increasing the amount of nitrogen fertilizer application, improvement was achieved in most of the evaluated characteristics of potato cultivars, including yield. Arinda cultivar had better conditions in terms of tuber yield and nitrogen uptake, utilization, and use efficiency compared to Agria.