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Ashwagandha (Withania somnifera L. Dunal) is an industrially important medicinal herb and root and is a rich source of bioactive withanolides. To investigate the impacts of different organic nutrient management practices on ashwagandha yield and quality, a field experiment was conducted for 2 consecutive years. The experiment was carried out in randomized bock designed (RBD) with treatments comprised of different organic manures (farmyard manure, vermicompost, and castor cake) and microbial consortium along with recommended doses of fertilizer and the control. The root yield parameters (root girth, length, and fresh and dry root weight) of ashwagandha were influenced significantly by the treatments containing organic manures and microbial consortium alone or in combination. The highest fresh (1505 kg ha−1) and dry (767 kg ha−1) root yields as well as total withanolide contents (0.947 mg g−1) were recorded under the treatment receiving castor cake + microbial consortium (T7) followed by application of vermicompost + microbial consortium (T8). Significant improvements in soil fertility status (mineral N, available P and S) and soil biochemical parameters (microbial biomass and enzymes) were observed under the treatments containing castor cake and vermicompost. A positive correlation coefficient (< 0.01) was found between dry root yield, withanolide content and soil properties (r = 0.34–0.64). Thus, the results indicate that castor cake and vermicompost could be promising nutrient source for production of quality medicinal herb by improving soil properties. [ABSTRACT FROM AUTHOR]

Kalmegh (Andrographis paniculata) is an annual herb with wide medicinal and pharmacological applications due to the presence of andrographolide, an important bioactive compound. Influence of organic nutrient sources on biological yield and bioactive principle of kalmegh was studied through field experiment for two consecutive years. The experiment was carried out in a split plot design where, organic sources (farmyard manure, vermicompost and castor cake) were applied as main plot treatments and microbial consortium and jivamrut were applied as subplot treatments. The highest fresh (17,347 kg ha−1) and dry (8050 kg ha−1) herbage yields were recorded with vermicompost followed by castor cake application. Bioactive compound (andrographolide) content in kalmegh was significantly influenced by the application of organic manures, microbial consortium and jivamrut. The result also reflected in total bioactive compound (andrographolide) yield where 9.7–53.7% increase in the main plot and 10.7–22.4% increase in the sub-plot treatment was recorded. Andrographolide yield was much higher with vermicompost and castor cake than the rest of the treatments. The application of vermicompost and castor cake resulted in significantly higher herbage and bioactive compound yield, which was significantly correlated with soil properties. Soil fertility and biological properties also improved with the application of organic sources, particularly vermicompost. Significant correlation between the soil properties and yield and bioactive compound content indicates that organic sources have beneficial impact on yield and quality of kalmegh through improving soil properties. Thus, application vermicompost could be a promising nutrient source particularly in organic cultivation of kalmegh. [ABSTRACT FROM AUTHOR]