Bioethanol yield of the sorghum × sudangrass hybrid under arid and semiarid conditions: Nitrogen dose effects, orthogonal comparisons, and component analyses

Abstract

The sorghum × sudangrass hybrid is significant as a biofuel crop due to its high biomass production, drought tolerance, adaption ability to various climatic conditions, and high sugar content in its stems. This study aimed to determine the effects of six different nitrogen dose treatments on ethanol yield, yield parameters, and fertilizer use relationships in sorghum × sudangrass hybrid plants in two locations in 2021 and 2022. The experiment was established according to the randomized block design with three replicates. Nitrogen treatments were applied as N0 (0 kg da–1), N5 (5 kg da–1), N10 (10 kg da–1), N15 (15 kg da–1), N20 (20 kg da–1), and N25 (25 kg da–1). Juice ethanol yield (JEY), lignocellulosic ethanol yield (LEY), and theoretical ethanol yield (TEY) values varied between 123.8–219.0 L da–1, 522.2–955.1 L da–1, and 646.0–1174.2 L da–1, respectively. JEY, LEY, and TEY values increased as the amount of nitrogen increased. The correlation analysis found a high positive relationship between all traits except acid detergent lignin. As a result of the orthogonal comparison, it was found that the nitrogen dose amount should be increased for JEY, LEY, and TEY. Principal components-biplot analyses explained 92.9% of the relationships between the studied parameters and the nitrogen dose levels. This study, conducted over two years and in two locations, determined that sorghum x sudangrass hybrid cultivation could be realized in terms of bioethanol yield under different nitrogen dose levels and that the ethanol yield potential is high.