Effect of humic acid and phosphorus fertilizer on seed and flower yield, photosynthetic pigments and mineral elements concentration in sour tea (Hisbiscus sabdariffa L.)

Document Type : Research Paper


1 Associate Professor, Agronomy and Plant Breeding Department, University of Shahrood, Iran

2 MSc., Agroecology, University of Zabol, Iran


This experiment was conducted as randomized complete block design with three replications in 2012 at University of Zabol. Experimental treatments included phosphorus fertilizer at three levels of 0, 100 and 200 kg.ha-1 as the first factor and foliar humic acid at four levels of 0, 750, 1500, 2250 g.1000 L water as the second factor. Results showed phosphorus treatment had significant effect on flower and seed yield. Yield components included biological yield, number of branches, number of capsules per plant, seed weight per plant and 1000 grain seed weight. Phosphorus treatment increased these traits and the highest seed yield (0.61 ton.ha-1) and flower yield (0.63 ton.ha-1) were obtained at the 100 kg.ha-1 treatment. P treatment significantly increased the photosynthetic pigments, soluble carbohydrate in leaves and seed phosphorus concentration. In this study, humic acid application by improvement yield components caused an increase in the grain yield. The highest grain yield was obtained at 1500 g. 1000 L water. Interaction between phosphorus fertilizer and humic acid, except biological yield and leaf soluble carbohydrate, had significantly effect on all of the yield components. The highest number of branches per plant, number of capsules per plant and 1000 seed weight were obtained by application of 1500 g.1000 L water humic acid and 100 kg.ha-1 phosphorus treatment.