Evaluation of organic fertilizers and soil amendments on yield and yield compounds of roselle (Hibiscus sabdariffa L.)

The application of organic inputs can be a suitable alternative to chemical fertilizers due to their many properties and reduction of environmental effects. Therefore, in order to evaluate the effects of organic fertilizers, research was conducted as a factorial base on a completely randomized block design in three replications on roselle (Hibiscus sabdariffa L.) in 2019 in Nazarabad, Karaj, Iran. The treatments included cow manure levels (0, 5 and 10 ton ha-1), vermicompost levels (0 and 15 ton ha-1) and biochar levels (0 and 10 ton ha-1). The results of this study showed that the application of cow manure, biochar and vermicompost promoted yield and yield compounds of roselle compared to control. In addition, the integrated application of cow manure, biochar and vermicompost effects on traits better than the main effects. The highest dry matter weight (1116.82 g m-2), fruit dry weight (456.82 g m-2), and soil respiration (0.37 µmol m-2 s-1), were related to the integrated application of cow manure, biochar and vermicompost. Thus, to promote roselle yield and yield compounds, the usage of organic fertilizers and soil amendments (cow manure, biochar and vermicompost) is a suitable alternative to chemical fertilizers.