Effect of Nitrogen and Boron Treatments on Harvest Index and Nitrogen Use Efficiency in Sugar Beet

The use of optimum nitrogen (N) and boron (B) fertilizers is important for yield and quality in sugar beet production. Therefore, it is necessary to determine the rate of use and recycling parameters of the applied nutrients by the plants in order to optimize the yield and quality in production. This study aims is to examine the effect of different doses of N and B treatment on sugar harvest index (SHI), nitrogen harvest index (NHI), and N use efficiency parameters and to determine the economic optimum nitrogen rates (EONR) in sugar beet. The experiment was set up in a randomized block factorial design with three replications. Five doses of N (0, 90, 180, 270, and 360 kg N ha( -1)) and four doses of B (0, 2, 4, and 6 kg B ha (-1)) were applied in the study. According to the results of the research, the SHI decreased statistically significantly with the increase of dose of the N treatment, but the NHI was not affected by the N treatment. The physiological efficiency of N in taproot dry matter yield and physiological efficiency of N in sugar yield decreased statistically significantly (p<0.01) with the increase in the dose of N treatment. A similar case was observed in the parameters of nitrogen agronomic efficiency (NAgE) and nitrogen uptake efficiency (NUpE). The increase in B treatment doses statistically significantly (p<0.01) increased the NAgE in the first year. The EONR, calculated using the quadratic model, was found to be 240 kg N ha (-1) on average of two years. As a result, the N use potential decreased with the increase of N doses applied to sugar beet. The use of EONR can be recommended for optimum yield and quality in the region.