This study was achieved during the two successive summer seasons of 2017 and 2018
at the Experimental Farm of Faculty of Agriculture, Fayoum University, Fayoum. The main
target of this study was to examin the influence of four rates (0, 50, 100 and 150 kg fed-1) of
sulphur and potassium humate (0, 10, 20 and 30 kg fed-1) as soil application and their
interactions on vegetative growth, flowering and chemical compositions of roselle (Hibiscus
sabdariffa) plant. The obtained results referred that using sulphur at the highest rate (150 kg
fed-1) significantly increased growth parameters (plant height and number of branches/plant),
some flowering and fruits characters (number of fruits plant-1 and fresh and dry weight of
sepals plant-1) and chemical constituents (N, P and K%, chlorophyll a+b, charbohydrate %,
Anthocyanins % and sepals acidity) compared with control. Plants treated with potassium
resulted in the highest significant values of all the above mentioned studied parameters. Also,
the interaction effect between sulphur and potassium shown, that the highest values of
vegetative growth and flowering parameters as well as and chemical composition were
resulted from 100 or 150 kg fed-1 sulphur combined with 30 kg fed-1 potassium humate
compared with control treatment.