Effects of the microbial organic fertilizer and plant density on growth, development and yield of roselle (Hibiscus sabdariffa L.) in Central Vietnam

Abstract

Roselle is a potential crop in Vietnam due to its wide adaptation and many uses. In Thua Thien Hue province – Central Vietnam, the roselle has been grown widely at Phong Dien district. However, local people were growing on their experience and mainly using inorganic fertilizers, which had affected the crop yield partly. In order to towards environmentally friendly and contribute to completing the growing process to expand the safe material area for roselle, the experiments were carried out during 2021 and 2022 to evaluate the effects of microbial organic fertilizer doses and planting density on the growth, development and yield of roselle. The experiment consisted of twelve treatments, with three doses of microbial organic fertilizer (0, 0.5, 1.5 tons/ha) and four planting densities (21000, 24000, 28000, 33000 plants/ha), arranged in a split-plot design with three replications for each treatment. The results showed that in the 0.5 tons/ha of microbial organic fertilizer application treatment and planted at 33000 plants/ha had the highest yield per plant in both crops (568.04 and 590.04 g/plant), with yields of 20.98 and 20.56 tons/ha, respectively. Therefore, it could be recommended to use that amount of microbial organic fertilizer and plant density in the process of growing roselle in Thua Thien Hue and similar ecological regions.