The effect of organic fertilizer application on forage, bioethanol and biogas production from sweet sorghum (Sorghum bicolor L. Moench)

This research was carried out in Çukurova conditions in order to investigate the effects of different organic fertilizer and nitrogen doses on forage, bioethanol and biogas production from sweet sorghum (Sorghum bicolor L. Moench) according to the split plot experimental design with 3 replications, with inorganic nitrogen fertilizer applications forming the main plots (0, 5, 10, 15 and 20 kg/da) and organic fertilizer applications (0, 250, 500, 750 and 1000 kg/da) forming the sub-plots. In the research, the highest dry matter yield (2684.26 kg/da) was obtained from the combined application of 750 kg/da organic fertilizer and 15 kg/da inorganic nitrogen dose, followed by the combined application of 250 kg/da organic fertilizer and 20 kg/da inorganic nitrogen dose (2646.47 kg/da), the combined application of 750 kg/da organic fertilizer and 20 kg/da inorganic nitrogen dose (2531.12 kg/da) and the application of only 20 kg/da inorganic nitrogen dose (2547.50 kg/da) with slight differences. In the research, the highest crude protein yield (159.52 kg/da) was obtained from the application of 250 kg/da organic fertilizer and 20 kg/da inorganic nitrogen dose together, followed by the application of 750 kg/da organic fertilizer and 20 kg/da inorganic nitrogen dose together (149.22 kg/da) with a slight difference. In the research, the highest total ethanol yield (755.04 L/da) was obtained from the application of 750 kg/da organic fertilizer and 20 kg/da nitrogen dose together, followed by the application of only 20 kg/da nitrogen dose (686.58 L/da) with insignificant differences. In the research, the highest methane yield (815.66 m3/da) was obtained from the combined application of 750 kg/da organic fertilizer and 20 kg/da inorganic nitrogen, followed by the combined application of 250 kg/da organic fertilizer and 20 kg/da inorganic nitrogen (796.22 m3/da) and the combined application of 750 kg/da organic fertilizer and 15 kg/da inorganic nitrogen (771.86 m3/da) with slight differences. These results show that for the sustainable forage and biogas production from sweet sorghum under Çukurova conditions, 250 kg/da organic fertilizer and 20 kg/da inorganic nitrogen application can be preferred, and for sustainable bioethanol production, 250 kg/da organic fertilizer and 10 kg/da inorganic nitrogen application can be preferred. Keywords: Sweet sorghum, forage, bioethanol, biogas, organic fertilizer