TY - JOUR AU - Panayotova, Galia AU - Kostadinova, Svetla AU - Velinov, Ivan PY - 2020/11/16 Y2 - 2024/03/28 TI - ENERGY EFFICIENCY OF NITROGEN FERTILIZATION IN DURUM WHEAT AND SORGHUM GRAINS JF - Proceedings of CBU in Natural Sciences and ICT JA - PNS VL - 1 IS - SE - DO - 10.12955/pns.v1.126 UR - https://ojs.cbuic.cz/index.php/pns/article/view/126 SP - 78-84 AB - <p>The objective of this study was to assess the energy efficiency of nitrogen fertilization in durum wheat and sorghum grains in the period 2017-2019. Bulgarian durum wheat variety Predel was studied at a stationary fertilizer trial on soil type <em>Pellic vertisols</em> at the Institute of Field Crops in Chirpan, Bulgaria. Grain sorghum hybrid EC Alize was investigated on the experimental field of the Agricultural University of Plovdiv, Bulgaria, on soil type <em>Mollic Fluvisols</em>. The crops were grown under non-irrigated conditions. The studied nitrogen rates were 0, 60, 120, 180, and 240 kg N.ha<sup>-1</sup>. In durum wheat, nitrogen was applied two times: one third at sowing, and the rest - as top dressing in the tillering stage.&nbsp; In sorghum, the total nitrogen was applied as pre-sowing fertilization before sowing. The nitrogen fertilizer was applied as NH<sub>4</sub>NO<sub>3</sub>. The experimental design was a randomized, complete block design with four replications with a size of experimental plots of 20 m<sup>2</sup> for both crops. The energy efficiency of nitrogen fertilization (h) was calculated as the ratio between the received energy from additional grain yield of wheat and sorghum, respectively, and the invested energy from fertilization. It was established that energy efficiency of nitrogen fertilization depended on the nitrogen rate and hydro-thermal conditions during the vegetation period of durum wheat and sorghum. The bioenergy coefficient of durum wheat widely varied from 0.79 (N<sub>240</sub> in 2018) to 4.44 (N<sub>60</sub> in 2017). The average for the period, the highest value of energy efficiency of nitrogen fertilization was obtained at the low rate N<sub>60</sub> The higher nitrogen rate of 240 kg N.ha<sup>-1</sup> was slightly effective. Under drought conditions during the vegetation period of sorghum, most effective was the application of rates N<sub>120</sub> with the highest energy coefficient ​​of 1.23. The application of 180 kg N.ha<sup>-1</sup> to sorghum was the most energy efficient under the favorable hydro-thermal conditions in 2018 and 2019, and the average for the period 2017-2019. A low N<sub>60 </sub>rate in grain sorghum was inefficient from an energy point of view. Durum wheat showed higher energy efficiency of nitrogen fertilization compared to grain sorghum.</p> ER -