The effect of nitrogen concentration on the
nutritional quality and microbial load of samples of Hibiscus
sabdariffa were studied. Samples of calyces harvested from three
different nitrogen levels viz; 0 kg N / ha, 30 kg N / ha and 60 kg N
/ ha were used. Nutritional composition and the microbial counts
of the calyces were determined. Highest significantly (P = 0.01)
different crude protein and nitrogen value of 12.06% and 1.93 %
were obtained from calyces fertilized with 60 kg N / ha. Ascorbic
acid content of the calyces increased with increase in nitrogen
levels. For the microbial load analysis, there was no significant
influence of nitrogen on the microbial load. However, the least
bacteria (2.6 x 104 cfu / ml) and fungi (5.68 x 105 cfu / ml) counts
were obtained from calyces fertilized with 30 kg N / ha.
Therefore, inorganic nitrogen fertilizer of up to 60 kg N / ha can
be applied to Roselle plant in order to increase some of the
nutritional constituents but should not exceed 30 kg N / ha for the
purpose of reduced microbial load