Abstract

Many medicinal plant species, including Rheum australe L. (rhubarb), are being exploited from the wild source at an alarming rate. This has resulted in the loss of biodiversity of the species. Roots of R. australe have been used in traditional medicine for years for treating various kinds of diseases. The species has been ruthlessly harvested from the wild source and has become endangered. Consequently, preventing the species from getting extinct and increasing the yield of R. australe has become a major concern. In the present investigation, an attempt was made to standardize the cultivation practices using organic manures and inorganic fertilizers and their impact on the amount of Rhein content in R. australe. The experiment comprised of 28 treatments, with three replications each, including one control treatment. The dry root weight recorded by the application of poultry, sheep and farm yard manure was 3878.40, 3200.0 and 3010.0 kg ha^-1, respectively. Dry root yield increased significantly with increasing levels of phosphorus and nitrogen as well. Application of organic manure and higher levels of inorganic fertilizers resulted in increase in the root weight, although the effect of their interaction was non-significant. Maximum dry root weight (6012.00 kg ha^-1) was observed in M₁P₂N₂ (20 tones poultry manure ha^-1, 100 kg phosphorus ha^-1, and 150 kg nitrogen ha^-1) compared to the lowest yield (2200.00 kg ha^-1) in M₃P₀N₁ (25 tones farm yard manure ha^-1, 0 kg phosphorus ha^-1, and 100 kg nitrogen ha^-1). The highest amount of Rhein content (0.393%) was observed in treatment M₁P₂N₂, displaying the maximum root weight, however, the least content (0.153) was observed in control treatment (M₀P₀N₀).

Key words:  Rheum australe, root weight, organic manure, inorganic fertilizer, morphological characters, rhein content.